Specification [Title of the Invention] HOT-ROLLED STEEL SHEET [Technical Field of the Invention] [OOO 11 The present invention relates to a hot-rolled steel sheet excellent in workabilit~:c orrosion resistance after coating, and notch fatigue properties, and particularly relates to a hot-rolled steel sheet with a high-strength composite structure excellent in stretch flailgeability, corrosion resistance after coating, and notch fatigue properlies. [Background Art] [OOOZ] In recent ye- in response to the demand for reduction in weight of various members for the purpose ofimproving fuel economy of vehicles, reduction in thickness by increasing strength of a steel sheet such as an iron alloy used for the members, and application of light metals such as an A1 alloy to the various members have beell proceeded. Howevei, as compared with heavy metals such as steel, the light metals such as an A1 alloy have an advantage of high specific strength, but are extremely expensive. For this reason, the application of ihe light metal such as atliU alloy is 111nited to special applicat~ons. Accordingly, in order to apply the reduciioil in the weight of the various members to a cheaper and wider range, it is necessary to reduce the thickness by increasing the strength of the steel sheet. [OOO3] Inil~enth e steel sheet 1s strengthened, the inaterial properties such as formability (workability) are generally deteriorated. Thus, in the developing of the high-st~eilgths teel sheet, it is an inlpotta~ipt robleinio achieve the high strength of the steel sheet without deteriorating the material properties. Particularly, the steel sheet used as vehicle membei s such as an inner plate men~ber, a structural member, and a suspension member requires stretch-flange fornlability, burring workability, ductil~ty, I fatigue durability, impact resistance, corrosion resistance, and the hke depending on the application, and it is imporlait to realize both of these material propert~esa nd the strength. [0004] For example, among the vehicle members, the steel sheets used for the structural memba, the suspension inember, and the like, which account for about 20% of the vehicle body weight are press-formed mainly based on stretch flange processing l and bumng processing after performing blanking and drilling by shearing or punching. For this reason, excellent &etch flangeability is required ibr such steel sheets. [OOOS] i'i'itll respect to the above-described problem, for example, Patent Document 1 discloses a hot-rolled steel sheet in which a martensite fraction, a size, a number density, and an average martensite gap are specified, and elongation (ductility) and hole expansion are excellent. Patent Document 2 discloses a hot-rolled steel sheet wluch is obtained by limitingthe average grain size of ferrite and a second phase and a carbon concentration of the second phase, and is excellent in burring worlcability. Patent Document 3 discloses a hot-rolled steel sheet whrch is obtained by winding at a 10-7 temperature after being kept at a temperature in a range of 750°C to 600°C fot 2 to 15 seconds, and is excellent in workability, surface quality, and flatness. [0006] IIowevei, in Patent Document 1, since a prima!?, cooling rate should be set to be equal lo or higher than 5O0C/s after completingthe hot rolling. the load app!~cd on an apparatus increases. In addition, in a case of setting the primary cooliilg rate to be equal to or higher than 5O0C/s, there is a problem in that unevenness in materials 1s caused by unevenness ill the cooluig rate. [0007] In addtion, as described above, m recent years, the demand for the application ofthe high-strength steel sheet to the vehicle members have beenrequired. In a case where the high-strength steel sheet is press-formed by cbld warking, craclis likely to occur at an edge of a portion which is subjected to the stretch flange fonning during the forming process. The reason for this is that work hardening occurs only on ail edge portion due to the strain which is iiltroduced lo a punched end surface ai the time of blanking. In tlie related art, as a method of evaluating a test of fhe stretch flangeability, a hole expansion lest has bemused. However, in the 1ioSe expansion test, breaking occurs without the strains in the circumferential direction are hardly distributed; however, in the actual process of components, strain distribution is present, and thus a gradient of the strain aid the stress in the viciility ofthe broken portion aEects a breaking linit. Accordingly, regarding the high-strength steel sheet, even if the sufficient stretch flangeability is exhibited in the hole expansion test, in a case of performing cold pressing the breaking may occur due to the strain distribution. [OOOS] The techniques disclosed in Patent Documents 1 to 3 disclose that in all of the inventions, tile hole expansion is improved by specifying only the structures observed using an optical microscope. I-Iou~everi,t is not clear whether or not sufficieilt stretch flangeabll~tyc an be secured even in consideration of the strain distribution. [OO09] 111 the vehicle members, in a case where the steel sheet is used foi coinponeuts having a poition with large stress concentration such as a drilling portion, among important safety components such as a wheel and a suspension, it requires notch fatigue properties in addition to the above-described streicli flangeability. Further, the strength and the notch fatigue properties of the coinponent are deteriorated when the sheet thickness is reduced due to the corrosion, and thus the steel used for the colnponents as described above also requires corrosion resistance (corrosion resistance after coating) aRer chemical conversion and electrodeposition coating. [OOlO] Regarding the in~provemenot f the notch fatigue properties, it has been reported that it is effective to set the structure to a composite stmcture having a ferrite and a secondary hard phase for reduction in crack propagation speed. For example, Patent Document 4 discloses a steel sheet in which the fdgue properties of materials without notches and the notch fatigue properties are realized by dispessing hard bainite or martensite in the structure havn~gfi ne ferrite as a primary phase. However, in Patent Document 4, the stretch flangeability is not disclosed at all. [ O O l l ] In addition, in Patent Docuinents 5 and 6, it has been reported that the crack propagation speed can be reduced by increasing the aspect ratio of marte~~siitne t he composiie structure. However, the targets for the above-described ones are steel plate, and thus do not have the excellent stretch flangeability required at the time of press forming of steel sheets. For this reason, it is hard to use the steel sheet disclosed in Patent Docun~ents5 and 6 as a steel sheet for vehicles. In addiiion, in Patent Documents 4,5, and 6, in order to form a conlposite structure of ferrite and nlartensae, Si 1s added for the puipose of prompting fenitic transfotl~aiionin many cases Iiowever, the steel sheet containing Si had a problem in that atiger stripe shaped scale pattern called red scale (Si scale) was generated on the surface of the steel sheei, and the corrosion resistance after coating was deteriorated. As described above, it is difficult to obtain a steel sheet satisfjiing all ofthe stretch flangeability, the notch fatigue properties, and the corrosion sesistance after coating which are required for vehicle members. [Prior Art Document] [Patent Docunient] [OO 121 [Patent Document 11 Japanese Unexamined Patent Application, First Publicatioil No. 2013-19048 [Patent Document 21 Japanese Unexamined Patent Application, First Fublicatiou No. 2001-303 186 [Patent Document 31 Japanese Unexamined Patent Application, First Publication No. 2005-213566 [Patent Document 41 Japanese Unexamined Patent Application, First Publication No. H04-337026 [Patent Document 51 Japanese Unexamined Patent Application, First Publication No. 2005-320619 [Patent Document 61 Japanese Unexainined Palenl Appllcatioi~F irst Publlcat~onN o. 1307-90478 [Disclosurc ofthe Invention] [Prohlenls to be Solved by the Inve~ltion] [0013] 'Tile present invention has been n~adein considetation of the above desc~~bed circumstance. An object of the present invention is to provide a high-strength hot-rolled steel sheet which is excellent in the corrosion resistance a h coating and can be applied to a member that requires stt~cstt retch flangeabiiity and notch fatigue properties. 111 the pi esent invention, the stretch flangeability means a value evaluated by a product of maximum forming height H (mm) of the flange and tensile strength (MPa) obtained as aresult of the test by the saddle type stretch flange test method, which is an index of the stretch flangeability in consideration of the strain distribution, and the excellent stretch flangeability means that the product ofthe maximum forming height H (111111) and the tensile strength (MPa) is equal to or greater than 19500 (mm-MPa). Furlher, the excellent notch fatigue properties means that a ratio FL/TS of notch fatigue limit FL (MPa) to tensile strength TS (&$Pa), which is obtained by a notch fatigue test is equal to or greater than 0.25. In addition, the high &enb& means that the tensile strength is equal to or greater than 540 MPa. Furlher, the excellent corrosion resislance after coating means that the maxitllum exfoliation width wluch is an index of the corrosion resistance after coating is equal to or less than 4.0 mm. In addition, in the related it has been known that as the stretch flangeability is improved, the ductility is deteriorated. However, the hot-rolled steel sheet of the present invention has the stretch flangeability iinproved, and can sailsfy the expression TS x EL2 13500 MPa . %, wl~iclis typical minimum ductility required for the vehicle members. [Means for Solving Ihe Roblei~l] [0014] According to the related artut?h,e improvement of the stretch flangeability @ole expansion) has been performed by u~clusionc ontrol, hotnogellization of structure, unification of structure, andlor reduction in hardness difference between structures, as disclosed in Patent Documents 1 to 3 In other words, in the related art, hole expansion or the like has been improved by controlling the structure which can be observed using an optical inicroscope [0015] In this regard, the present inventors made an intensive study by focusing an intragranulai orientalion difference in grains in consideration that the stretch flangeability under the presence of the strain distribution cannot be improved even by controlling only the structure observed using an optical microscope. As a result, it was found that it is possible to greatly improve the stretch flangeability by controlling the ratio of the grains in \vhich the intragranular orientation difference is in a range of 5" to 14' with respect to the entire grains10 be within a c&n range. [0016] Thc present invention is configured onthe basis ofthe above findings, and the gists thereof are as follows. [0017] (I) Ahot-rolled steel sheet according to one aspect of the present invention includes as a chemical conlposition, by mass%, C: 0.020%to 0.070%, Mn: 0.60%to 2.00%, Al: 0.10% to 1.00%, Ti: 0.015%to 0.170%, Nb: 0 005%lo 0.050%, Cr: 0% to 1.0%, TI. 0% to 0.3009'0, en: 0%to 2.00%, Ni. O%to 2.00%, Mo: O%to 1.00%, Mg: O%to 0.0100%, Ca: 0% to 0.0100n/o, WM: 0% to 0.1000%, B: 0% to 0.0100%, Si Limited to equal to or less than 0.100%, P: limited to equal to or less than 0.050%, S: limited to equal to or less than 0.005%, and N: limited Lo equal lo or less than 0 0060%, with the innainder of Fe and 1mp:unties; and in which a &ructure includes, by an area ratio, ferrite and baiilite in a range of 80% to 98% in total and nlartensite in a range or 2% to lo%, and in which in the structure, in a case where a boundary having an orientation difference of equal to or greater than 15" is defined as a grain boundary, and an area which is surrounded by tlie grain boundary, and has an equivalent circle diameter of equal to or greater than 0.3 pm is defined as a gram, the ratlo of the grains having an mtragranular orientation difference in a range of 5" to 14O is, by the area ratio, in a range of 10% to 60%. [OOlS] (2) In the hot-rolled steel sheet described in the above (I), the chemical composition may co~ltainb, y mass% one or two or more of V: 0.010% to 0.300%, Cu: 0.01% to 1.20%, Ni: 0.01% to 0.600/, and Mo: 0.01% to 1.00%. 100 191 (3) In the hot-rolled steel she& described in the beove (1) or (2), the chernicd composition may contain, by mass%, one or two or more of Mg: 0.0005%to 0.0100% Ca: 0.0005%to 0.0100%, and REM. 0.0005%to 0.1000%. [0020] (4) In the hot-rolled steel sheet described in any one of the above (1)io (3), the chemical composition may co~ltaiibl y mass%, B: 0.0002%to 0.0020%. [0021] (5) In tlie hot-rolled steel slleet described in any one of the above (1) to j4), a tensile strengtll may be equal to or gseater U~an 540 MPa, and a product ofthe tensile strength and a max~inum forming height in a saddle type stretch flange test may be equal to or seater than 19500 nnmMPa. [Effects of the Invention] [0022] Accord~ngto the above-described aspects of the piesent invention, it is possible to provide a high-strengih hot-rolled steel sheet which has high strength, call be applied to a member that requires strict stretch flangeability, and is excellent in the stretch flangeability, the notch fatigue properties, and the corrosion resistance after coatmg. [Brief Description of the Drawings] [0023] FIG 1 is an analysis result obtained by EBSD at ti4 portion (a 114 thickness position &oin the surface in the sheet thickness direction) of a hot-rolled steel sheet according to the present embodiment. FIG 2 is a diagram showing a shape of a saddle-shaped formedproduct which is used in a saddle type stretch flange test method. FIG 3 is a diagram showing a sbape of fatigue test piece used for evduaiing the notch fatigue properties. [Embodiments ofthe Invention] [a0241 Hereinafter, a hot-rolled stezl sheet (hereinafter, refirred to as a hot-rolled steel sheet according to the present embodiment in some case) of the embodinlent of the present invention will be described in detail. The hot-rolled steel sheet according to the present embodiment includes, as a chemical composition, by mass%, C: 0.020% to 0.070%, Mn. 0.60% to 2.0096, A: 0.10% to 1.00°/4. Ti: 0.015%to 0.170%, Nb: 0.005%to 0.050%, and optionally one or more of Cr. equal to or less than 1.0°4, Tr equal to or less than 0.300%, Cu: equal to or less than 2.00°h, NNi: equal lo or less tllan 2.00%, Mo: equal lo 01 less than 1.00%. Me: equal to 01 less than 0100% Ca. eqnal to or less than 0.0100%, REM. equal to or less than 0.1000%, B. equal to or less than 0.0100%, Si: limited To equal lo or less than 0.1000/4. P: limited to equal to or less than 0.050%, S: limited to equal to or less than 0.005%, and N: lnnited to equal to or less than 0.0060%, with the remainder of Fe and impurities; and a structure which includes, by area rxtio, ferrite and baiiute in a range of 80% to 98% in total andmartensite in a range of 2% to 10940, andin the structure, in a case where a boundary having an orientation difference of equal to or greater than 15" is defined as a grain boundary, and an area \vhich is surrounded by the grain boundary, and has an equivalent circle dianieter of equal to or greater than 0.3 pm is defmed as a grain, the ratio of the grains having an intragranular orientation difference in a range of 5" to 14" is, by area ratio, in a range of 10% to 60%. [(I0251 Firsf the reason for limiting Ule chemical composition of the hut-rolled steel sheat according to the preseut embodiment will be described The amount (%) ofthe respective elements is based on mass%. [0026] C: 0.020% to 0.070% C is an element wwhich forms a precipitate in the stezl sheet by being bonded to Nb, Ti, and the lilce, and contributes to improvement of the stlength of steel by precipitation strengthening. Further, C greatly affects the generation of martensite. For this reason, the lower limit of the C content is set to 0.020% The lower limit of the C content is preferably 0.02596, and the lower limit of the C content is further preferably 0.030%. On the other hand, when the C content 1s greater than 0.070%, the stretch flangeability and the weldability are deteriorated Thus, the upper limit of the C content is set to 0.070%. The upper limit of the C content is preferably 00.0650/o, and the upper linxit ofthe C content is pieferably 0.060%. [00i7] Si: equal to or less than 0.100% Si is an element which decreases a melting point of a scale, and increases adhesion between the scale and a base steel base metal ease inaterial). When the Si content is increased, a scale pattern occurs and chemical convertibility is deteriorated, which causes the corrosion resistance aRer coating to be deteriorated. For .this reason, the Si content is required to be limited. When the Si content is greater than 0.100%, the corrosion resistance aRer coating is remarkably deteriorated. Thus, the Si content is liinited to be equal to or less than 0.100%. The upper liinit of the Si content is preferably 0.050%, and the upper limit of the Si content is further preferably 0.040%. The Si content may be 0%. [OOZS] k h 0.60% to 2.00% Mn is an element which contributes to the improvement of the strengt11 of steel by the solid solution strengthening andor improving the hardenability of the steel. In order to obtain the aforementioned effect, the lower limit of the Mn content is setto 0.60%. The lower limit of the Mn ont tent is preferably 0.70%, and the lower limit of the Mn content is hrther preferably 0.80%. On the other hand, when the Mn content is greater than 2.00%, the sketch flangeability is deteriorated. For t l ~rsea son, the upper limit of the Mn content is set 2.00°4. The upper limit ofthe Mn content is preferably 1 5096, and is further preferably the upper limit of the Mn content is 1.20%. [0029] Al. 0 lO%to 1.00% Al is an effective element as a deoxid~zinga gent of molten steel In addition, in the hot-lolled steel sheet according to the present embodiment, A1 is an elemeut having an eEat of controlling the ratio of the grains having the intragranular orientation diiret ence in arange of 5" to 14" to be in a range of 10% .to 60%. It is considered that the aforementioned effect is related to the fact that Al has an effect of greatly increasing a temperature Ar3 of the steel sheet, and thus when Al is contained the transformation strain introduced in the grain is decreased In order to obtaln such effects, the lower limit of the Al content is set to 0.10%. The lower limit of the Al content is preferably 0.1396, and the lower limit of the A1 content is fixther preferably 0.15%. On the other hand, the Al content is greater than 1.00%, the toughness and the ductility are remarkably deteriorated, and thus breaking may occur during the rolling. For this reason, the upper limit of the A1 content is set to 1.00%. The upper limit of the Al content is preferably 0.50% and the upper limit ofthe A1 content is further preferably 0.40%. [0030] Ti: O.O15%to 0.170% Ti is an element which is finely precipitated m the steel as carbide and improves the strength of steel by precipitat~oils trengthening. In addition, Ti is an element for fonning carbide (Tic) so as to fix C, and limit the generation of cementite which is harmful to the stretch flangeability. In order to obtain the above-described effects, the lower limit of the Ti content is set to 0.015%. The lower limit ofthe Ti content is p~eferably0 .020%, and the lower limit of the Ti content is further preferably 0.025%. On the other hand when the Ti content is greater than 0.170%, the ductil~ty is deteriorated. For this reason, the lipper liin~ot f the Ti content is set to 0.170%. The upper lnnit of the Ti content is prefe~ably0 .150%, and the upper limit of the Ti content is Eurlher preferably 0.130%. [003 11 Nb. 0 005% to 0 050% Nb is an element which is finely precipitated in the steel as carbide and improves the strength of steel by precipitation strengthening. In addition, Nb is an element for forming carbide (NbC) so as to fix C, and liinit the generation of cementite which is harmful to the stretch flangeability. In order to obtain the above-described effects, the lower limit of the Nb content is set to 0.005%. The lower limd of the Nb content is preferably 0.010%, and the lo\ver limit ofthe Nb content is fiwiher preferably 0.015%. On the other hand, wh&tlie Nb content is greater than 0.050%, the ductility is deteriorated. For this reason, the upper limit of the Nb content is set to 0.050%. The upper limit of the Nb content is preferably 0.040%, and the upper liinit offhe Nb content is further preferably 0.030%. [0032] P: equal to or less than 0.050% Pis an impurity. P causes the toughness, the workability, and the weldability to be deteriorated, and thus the less the content, the better. However, in a case where fl~eP content is greater than 0.050%, the stretch flangeability is remarkably deteriorated, and thus the P content inay be limited to be equalto or less than 0.050%. The P content is further preferably equal to or less than 0.030%. Although, there is no need to particularly determine the lowcr limit of the P content, excessive reduction of the P conteut is undesirable fromthe viewpoint of manufacturitlg cost, and thus the lower liinit ofthe P content may be equal to or greater than 0.005%. 100331 S: equal to or less than 0.005"b S is an element which is not only causes cracks at the time of hot rolling, but also fonns an Atype inclusion \"r'l11~1i1n al~etsh e st~etclfil angcabillty deteriorated. For this reason, the less the S content. the better. However, when the S content is greatc; than 0.005%, the stretch flangeability is remarkably deteriorated, and thus the upper limit of the S content may be limited to be 0.005%. The S content is fu&er preferably equal to or less than 0.003%. Althougk there is no need to particularly determine the lower limit of the S content, excessive reduction of the S content is undesirable &om the viewpoint of manufacturing cod, and thus the lower limit of S content may be equal to or greater thal0.001%. [0034] N: equal to or less than 0.0060% N is an element which fosms a precipitate with Ti, Nb in preferenceto C, and decreases Ti and Nb effective for fixing C. For this reasoiL the less the N content, the better. However, in a case where the N content is greater than 0.0060%, the stretch flangeability is remarkably deleride4 and thus the upper limit ofthe N content is limited to be 0.0060%. The N content is further preferably equal to or less than 0.0050%. [0035] The above-described elements are base elemenls contained in the hot-rolled steel sheet according to the present embodiment, and a chenlical composition which contains such base elements, with the remainder of Fe and impurities is a base coil~positiono f the hot-rolled steel sheet according to the present eillbodiment. However, in addition to the base elements (instead of a portion of Fe of the remainder), the hot-rolled steel sheet according to the present embodiment fu~therc ontains, if necessaiy, one 01 illore selected fronxthe chemical compositio:l of Cr, I< Cu, Ni, Mo, Mg, Ca, REM, and B (selective elements) within a range described beloxv. It is not necessary to contain the following el-ments, and thus the lol?r?r limit of the content is 0%. Even lien such selectlye elenlents are unavoidably co~ltaininatedi n the steel, the effect in the present embodiment is not impaired. Here, the impurities are elements contaminated in the steel, which are caused G-omraw materials such as ore and scrap at the time of industrially manufacturing the alloy, or caused by various factors in the inanufacturn~gp rocess, and are in a11 allowable range which does not adversely affect the properties of the hot-rolled steel sheet according to the present embodiment. [0036] Cr: 0 to 1.0% Cr is an element which contributes to improvement of the strength of the steel sheet. In a case of obtaining such an effect, the Cr content is preferably equal to or greater than 0.05%. On the other hand, when the Cr content is greater than 1.0%, the effect is satmated and the economic eEciency is deteriomted Accor&x?y, even in a case of containing Cr, the upper limit ofthe Cr content is preferably 1.0%. [0037] V: 0% to 0.300% V is an element which improves the strength ofthe steel sheet by the precipitation strengthening or solld solution strengthening. In a case of obtaining such an effect, the V content is preferably equal to or greater than 0.010%. On the other hand, when the V content is greater than 0.300%, the effect is saturated and the economic efilcieilcy is deteriorated. Accordingly, even in the case of containing V, the upper limit of the V content is preferably set to 0.300%. [0038] Cu: 0% to 2.00% Cu is an element which inlproves the strength of the .tee1 sheet by the precipitatioil ctiengtl~eningo r the solid solution strengtl~ening. In a case of obtailliilg such an effect, the Cu coilteilt is preferably equal to or greater than 0.01%. On the other hand, when the Cu coiltent is greater than 2.00%, the effect is saturated and the economic eEciency is deteriorated. Accordingly, even in a case of containing Cy the upper limit of the Cu content is preferably set to 2.00%. Ho\vever, when the Cu content is greater than 1.20% defects due to the scale may occur on the suiface of the steel sheet. Accordingly, the upper limit of the Cu content is preferably set to 1.20%. [0039] Ni: 0% to 2.00% Ni is an element which improves the strength of the steel sheet by the precipitation strengthening or the solid solution strengthening. In a case of obtaining such an effect, the Ni content is preferably equal to or greater t11ai 0.01% On the other hand, when the Ni content is greaier than 2.00%, the effect is satusaled atld the economic efficiency is deteriorated 111 addition the ductility is also greatly deteriorated. Accordingly, even in the case of containing Ni, ihe upper limit of the Ni content is preferably set to 2.00%. When the Ni content is greater than 0 60%, the ductility starts to be deteriorated, and thus the upper liinit ofthe Ni content is preferably set to 0.60%. [0040] Mo: 09,oto 1.00% Mo is ail element which improves the strength of the steel sheet by the precipitation st~'l@l~eningo r the solid solution strengthening. In a case of obtaiiiing such an effect, the Mo content is preferably equal to or greatci- than 0.01%. On the other hand, wheil the Mo content is gseafet than 1.00%, the effect is saturated and the economic efficiency is deteriorated. kccordingly, even in the case of containing Mo. the upper lilnit ~f ithe Mo content is preferably set to 1 00% [0041] Mg: 0% to 0.0100% Mg is ail element which improves the workability ofthe steel sheet by controlling the form of nonmetallic inclusions that become the starting point of breaking and causes deterioraiioil of the workability. In a case of obtaining such an effect, the Mg content is preferably equal to or greater than 0.0005%. On the other hand, when the Mg content is greater than 0.0 loo%, the effect is saturated and the economic efficiency is deteriorated. Accordinglj: even in the case of containing M& the upper limit of the Mg content is preferably setto 0.0100%. [0042] Ca: 0% to 0.0100% Ca is an element which improves the workability ofthe steel sheet by controlling the form of nonmetallic inclusions that become the starling point of breaking and causes deterioration of the workability. In a case of obtaining such a1 effect, the Ca content is equal to or greater than 0.0005%. On the other land when the Ca content is greater than 0.0100%, the effect is saturated and the economic efficiency is deteriorated. Accordingly, even in the case of containing Ca, the upper limit of the Ca content is preferably set to 0.0100%. [0043] E M : 0% to 0.1000% E M (lare earth element) is an clcinent which impro~resth e workability of the steel sheet by controlling the form of noilnielallic inclusions that become the starting point of brealculg and causes deterioration of the workability. I11 a case of obtaining such an effect. the REM content is preferably equal to or greater than 0.0005% On the other hand, when the REM coi~lei~s ~set ater than 0.1000%, the effect is saturated and the econonlic efficiency is deteriorated Accordingly, even in a case of containing REM, the upper liillit of the REM content is preferably set to 0.1000%. [0044] B: O%to 0.0100% B is an element which is segregated in the grain boundaay and improves toughness at a low temperature by enhancing the strength ofthe gr2in boundary. In a case of obtaining such an effect. the B content is preferably equal to or greater than 0.0002%. On tlie other hand, when the B content is greaier than 0.0100%, the effect is saturated and the economic efficiency is deteriorated. Accordingly, even in the case of containing 3, the upper limit of the B content is preferably set to 0.0 100%. In addition, B is an element for strongly improving the hardenability, and when the B content is greater than 0.00200/4 the gain ratio havkg the infragranular orientdon difference in a range of 5%to 14" is greater than 60% by area ratio. Accordingly, the upper limit of the B content is preferably set to 0.0020%. [0045] The above-described elements may be contained in the range which does not impair the effect in the present embodiment. For example, the present inventors have confirmed that Sn, Zr, Co, Zn, and W do not impair the effect in the present embodiment eve11 when those are contained by equal to or less than 1% in total. Among those elements, Sn is preferably equal to or less than 0.05% from the aspect that defects may occur at the time of the hot rolling. [0046] Next, ille structure (metallograpl~ics tmcture) of the hot-rolled steel sheet according to the present embodiment nlill be described. It is necessary that the hot-rolled steel sheet accotding to ilie present embod~ineiltc ontain, by area ratio, ferrite and bainite in a range of 80% to 98% in total, and martensite in a range of 2% to lo%, in the struciure observed using an optical microscope. With such a structure, it is possible to improve the strength and the stretch flangeability in well balance. When the total amount of the ferrite aud the bainite is less than 80% by area ratio, the balance between the strength and the stretch flangeability is deteriorated, and thus H x TS which is a product of maximumforming height N (mm) and tensile strengthTS (MPa) is 19500 mmMPa. In addition, when the total area ratio ofthe ferrite and the bainite is greater than 98%, or the area ratio of the martensite is less than 2%, the notch fatigue properties are deteriorated, and thus the relationship expressed by FWTS 2 0.25 cannot be satisfied Further, when the area ratio of martensite is greater than lo%, the stretch flangeability is deteriorated. Although eaeh of the fmclion (fhe area d o ) of the f&te and the bainite is not necessarily limited, when the hetion of the bainite is greater than 80%, the ductility may be deteriorated, and thus the fraction of the bainite is preferably equal to or less than SO%, and is further preferably less than 70%. The structure of the remainder other than ferrite, bainite, and martensite is not particularly limited, and for example, it may be residual austenite, pearlite, or the like However, the ratio of the remainder is preferably equal to or less than 10% by area ratio in order to limit the deterioration of the stretch flangeability. [0047] The structure fraction (the area idio) can be obiailled using the followi~lg method. F~rsta, sample collected from the hot-rolled steel sheet is etched using nital. Mer etching, a sluuctxre photograph obtained at a 114 thickness positloll in a visual field of 300 pix x 300 pnl using an optical microscope is subjccied to image analysis, and thereby the area ratio of fernte and pear-lrle, atid ihe total area ratio of bainite and martensite are obtained. Then, with a sample etched by LePera solution, the structure photograph obtained at a 114 thickness position in the visual field of300 pm x 300 pm is subjected to the image analysis using the optical microscope, and thereby the total area ratio ofresidual austenite and martensite is calculated. Further, with a sample obtained by grinding the surface to a depth of 114 thickness fi-om in normal direction bf the rolled surface, the volume fraction of the residual austenite is obtained through X-ray diffraction measurement. The volunle fraction of the residual austenite is equivalent to the area ratio, and thus is set as the area ratio of the residual austenite. Wifh such a method, it is possible to obtain the area ratio of each of femte, bainite, martensite, residual austenite, and pearlite. I00481 In the hot-rolled steel sheet accordingto the present embodiment, it is necessary to further control the structure observed using the optical microscope to be within the above-described range, and to control the ratio of the grains having the intragranular oiicntation difference ilia range of 5" to 14Q, obtained using an EBSD method (electron beam back scattering diffraction pattern analysis method) frequently used for the crystal orientation analysis. Specifically, in a case where the grain boundary is defined as a boundary liaving the orientation difference of equalio or higher than 15", and an area which is surrounded by the grain boundary, and has an equivalent circle diameter of equal to or greatel than 0.3 p is defined as a grain, the ratio of the grains having the intragranular oiientation difference in a range of 5" to 14O is set to be in a iaiige of 10% to 60% by aiea ratio, with respect to the entire grains. The gains having the above illtragranular orientation difference are effective to obtain a steel sheet which has the strenglh and ihe workabilit~ in the excellent balance, atldlhus when the ratio is controlled, it is possible to greatly improve ihe stretch flangeability while mainta~ninga n intended steel sheet strength. When the ratio of the grains l~avingth e intragranular orienlation difference iu a range of 5 O to 14" is less than 10% by area ratio, the stretch flangeability is deteriorated. In addition, when the ratio ofthe grains having the intragranular orientation d~fferencein a range of 5' to 14' is greater than 60% by area ratio, the ductility is deteriorated. It is considered that the intragranular orientation difference is related to a dislocation density contained in the grains. Typically, the increase in the intragranular dislocation density causes the workability to be deteriorated while bringing about the improvement of the strength. However, in the grain in whichthe intragranular orientation difference is controlled to be in a range of 5" to 14O, it is possible to improve the strength withoa deterioraiingthe workability. For this reason, in ihe hot-rolled steel sheet according to ihe present embodiment, the ratio ofthe gains having the intragranulas orientation difference in a range of 5" to 14" is controlled to be in a range of 10% to 60%. The grains having the intragranular orientation difference of less than 5O are excellent in the workability, but are hard to be highly strengthened, and the grains having the intragranular orientation diirerence of greater than 14" are different in deformability from each other, and thus do not contribute to the improvement of the stretch flangeability. [0049] The ratio ofthe grains having the l~ltragranularo rientation difference in a range of 5" to 1 3 O can be measured by t11e following metl~od. First, regarding a vertical section of a position of depth of 1/4 (U4 portion) thickness t from ~ulfaceo fthe steel sheet in a rolling direction, an area of 200 pm in Ihe rolling dnectiim, and 100 pm in the normal direction of the lolled surface is subjected to EBSD analysis at a measurement gap of 0 2 pm so as to obtain nystal orientation infomat~on. Here, the EBSD analysis is performed using an apparatus which is configured to include a thermal field emission scanning electron microscope (JSM-700lF, manufactured by JEOL) and an EBSD detector (HIKARI detector manufactured by TSL), at an ailalysis speed in arange of200 to 300 points per second. Then, with respect to the obtained crystal orientation information, an area having the orientation difference of equal to or greater than 15" and an equivaient circle diameter of equal to or greater than 0.3 pnl is defined as grain, an average intragranulax orientation diierence of the grains is calculated, and the ratio of the grains having the intragranular orientation difference in a range of 5" to 14' is obtained. The grain and the average intragranular orientation difference defined as described above can be calcnlatedusing software "OiMAaa1ysis (trademarky' -bed to an EBSD analyzer. The "intragranu1ar orientation difference" of the present invention means "Grain Orientation Spread (GOS)" which is an orientation dispersion in the grains, and the value thereof is obtained as an average value of reference crystal orientations and misorientaiions ofall ofthe measurement points within the same grain as disclosed in Nan-Patent Document 1. In the present embodiment, the reference crystal orientation is an orientation obtained by averaging all of the measurement pokts in the same grain, a value of GOS can be calculated using "OIM Analysis (trademark) Version 7.0.1" which is soRware attached to the EBSD analyzer. [0050] FIG 1 1s an EBSD analysis result of an area of 100 pm x 100 pm on the vertical section tn the rolling direction, aihicl~is 114 portion of the hot-rolled steel sheet accolding lo the piesent embodiment In FIG 1, an area which is surrounded by the grain boundary having the orientatioil diffaence of equal lo or @eater than IS0, and has the iiltragranular orientation difference in a range of 5" to 14' is shown in black. [0051] Inthe present embodiment, the stretch flangeability is evaluated using ihe saddle type stretch flange test method in which the saddle-shaped formed product is used. Specifically, the saddle-shaped formed product simulating the stretch flange shape fornled of a linear portion and an arc portion as shown in FIG 2 is pressed, and the stretch flangeability is evaluated by a maximum forilliiy height at this time In the saddle type stretch flange test of the present embodinlent, the maximum fonning height 1-1 (min) when the clearance at the time of punching a corner portion is set to 11% is measured using the saddle-type fmned product in which a radius of curvature R of a corner is set to be in a range of 50 to 60 mm, and an opening angle 6 is set to 120". Here, the clearance indicates the raiio of a gap between a punching die and a punclk and the thickness ofthe test piece. Actually, the clearance is determined by combination of a punching tool and the sheet thickness, and thus the value of 11% means that clearalce satisfies arange of 10.5% to 11.5%. The existence of the cracks having a length of 1/3 ofthe sheet thickness are visually observed after forming, and then a forming height of the limit in which the ctaclts are not present is determined as the maximum forming height. [0052] In a hole expansion test which is used as a test method corresponding to the stretch flange formability in the related arf the breaking occurs without strains are ~llostlyd istributed in the circumfereiltial direction, and thus the stsalil and the gradient of stress in the vicinity of the broken portion during hole expansion test are different from that ill the case of actually forming the stretch flange In addition in the hole cxpansioil test, the evaluation does ilot reflect the oiigi~iasl tretch flange foriliing, since, for example, the evaluation is performed when the rupture of the thickness penetration occurred. On the other hand, in the saddle type stretch flange test used in the present embodiil~en Mer hot rolling, the hot-rolled steel sheet is cooled. In the cooling process, it is preferable that the hot-rolled steel sheet after completingthe hot ~ollingis cooled (first cooling) downto a temperature range in a range of 650°C to 750°C at a cooling rate of equal to or greater than 1O0C/s, and the hot-rolled steel sheet is held for 3 to 10 seconds in the temperature range, and thereafter, the hot-rolled steel sheet is cooled (second cooling) down to 100°C ata cooling rate of equal to or greater than 3O0Cis. When the cooling rate in tile %st cooling is lower than 1QoC/st, he transformation occurs in the para-equilibrium state at a teinperature higher that1 a preferable te-mperatsre range, and &m the d o ofthe grains having the intragranular orientation dEerence in a range of 5" to 1 4 O becomes less than lo%, which is not preferable. In addition, when a cooling stopping temperature in the first cooling is lower than 65OoC, the transformation occurs in the para-equilibrium slate at a teinperature lower than a preferable temperature range, and thus the ratio of the grains having the intragranular orientation difference in a range of 5" to 14' becomes less than lo%, which is not preferable. On the other hand, when the cooling stopping teinperature in the first cooling is liigl~etrh an 750°C, the transforn~at~oonc curs in the para-equilibrium state at a temperature higher than a preferable tenlperature range, and Ihus the ratio of the grains having the intragr,~nularo rlentation diffe~en ce en a range of 5" to 14' becomes less than lo%, which is 1101 preferable. In addition, even when a holding time is shorter than 3 seconds at a temperature range of 650°C to 750°C, the ratio ofthe granls having the intragranular orientatiou difference iil a range of 5" to 14' becoilles less than lo%, which is not prefeiahle. When the holding time at a temperature range of 650°C to 750°C is longer than 10 seconds, cementite h a d 1 to the stretch flangeability is likely to occur, which is not preferable. In addition, when the cooling rate of the second cooling is lower than 30°C/s, cementite harmful to the stsetch flangeability is likely to occur, which is not preferable. In add~iionw, henthe cooling stopping temperature of the second cooling is higher than 10O0C, the martensite fraction is less than 2%, wluch is not preferable. Altliough the upper liinit of the coolmg rate in the first cooling and the second cooling is not necessarily limited, the cooling rate may be set to be equal to or lower than 200°C/s in consideration ofthe equipment capacity of the cooling facility. [0060] Accordingto the above-described manufacturing method, it is possible to obtain a sirudure which includes, by area Mia. fenite and bainite in a range of 80%io 98% in to% and mastensite in a range of2% to 10%, and in which the ratio ofthe grains having an intragranular orientation difference in a range of 5" to 14' is, by area ratio, in a range of 10% to 60%, when a boundary having an orientation difference of equal to or greater than 15O is defined as a gain boundary, and an area urhich is surrounded by the grain boundary and has an equivalent circle diameter of equal to or greater than 0.3 pm is defined as a grain. In the aforemeiltioned manufactusing method, it is important that processed dislocations are introduced into austenite by controlling the hot rolling conditions, and then the processed dislocations introduced by controlling the cooling conditions appropriately remain That is, ihe hot rollillg conditions and the cooling conditions each have an influence, it is important to control these co~lditionsa t the same time. A known method ma) be used for conditioils other U1an the above-described ones, and there is no particulal limilat~on. In addition, there is no problem even if a heat treatment is performed as long as the area ratio of the above-n~entioaeds tructure can be kept. [Examples] [0061] He1 einaRer, the present invention will be described more specifically with reference to examples ofthe hot-rolled steel sheet ofthe present invention; however, tile present invenfion is not limited to Example described below, and call be implemented by being properly modified the extent that it can satisfy the object before and after description, which are all included in the technical rage of the present invention. [0062] In the present examples, firsf the steel having the composition shown in the following Table 1 was melted so as to produce a slab, the slab was heated, and was subjected to hot and rough rolling, and subsequently, the finish rolling was performed under the conditions indicated in the followrllg Table 2. The sheet thickness a h the finish rolling was in a range of 2.2 to 3.4 mnl Ar3 (OC) indicated in Table 2 was obtained kom tile composition shown in Table 1 using the following Expression (2). Ar3 = 970 - 325 x [C] + 33 x [Si] + 287 x [PI + 40 x [All - 92 x ([Mn] + [Mo] + [Cu])-46 x ([Cr] a [Nil) . . . (2) In addition, the cumulative strains at the last three passes were obtained by the following Expression (1). ~eff=. Czi(t,T) .. . (1) Here, ~i(t,T=) ~ i ~ / e x ~ ( ( t / t ~ ) ~ ' ~ } , tR = LO . exp(QRT), 10 = 8.46 x 1V6, Q = 183200 J, and R = 8.3 14 J/K . mol, E ~ Ore presents a logarithmic strain at the time of roll~ngre duction, t represents a cunlulative time immed~atelyb efore the coolnlg in the pass, and T represents a roiling temperature in the pass. The blank column in Table 1 means that the analysis value was less than the detection limit [0064] [Table 21 [OOGS] With respect to the obtained hot-rolled steel sheet, fraction of each structure (the area ratio), and the ratio of the grains having the intragranular orientation difference in a range of So to 1 4 O were obtained. The structure fraction (the area ratio) was obtained usingthe following method. Fusf a saillple collected fromthe hot-rolled steel sheet was etched using nital. After etching, a structure photograph obtained at a 114 thickness position in a visual field of 300 pm x 300 PI using an optical microscope was subjected to image analysis, and thereby the area raiio of ferrite and pearlite, and the total area ratio bainite and marlensite were obtained. T11e11, with a sample etched by LePera solution, the structure photograph obtained at a 114 thickness position in the visual field of 300 pm x 300 p using the optical microscope was subjected to the image analysis, and thereby the total area ratio of residual austenite and marlensite was calculated Further, with a sample obtained by grinding the surface to a depth of 114 thickness from in nonnal direction of the rolled sudace, the volume hction of the iesidual austenite was obtained through X-ray difiadion measurement. The volume fraction of the residual austenite was equivalent to the area ratio, and thus was set as the area ratio of the residual austenite. With such a meti~odt,h e area ratio of each of ferrite, bainite, inartensite, residual austenite, and pearlite was obtained. Further, the ratio of the grains having the inhagranular orientation difference irk a range of So to 14" was measured using the following method. First, regarding a vertical section in a lollins direction of a position of depth of 114 (ti4 podion) t!uckness t from surface of the steel sheet, an area of 200 pm in the roll~ilgd irection, aild 100 pm in the noimat direction of the rolled sutrface was subjected lo EBSD analysis at a measurement gap of 0.2 pm so as to obtain crystal orientation illformation. Here, the EBSD analysis was performed us~nga n apparatus which is configured to include a thennal field enussion scanning electron microscope (JSM-7001F, manufactured by JEOL) and an EBSD detector (HIKARI detector manufactured by TSL), at an analysis speed in a range of 200 to 300 points per second. Then, with respect to the obtained crystal orientation informailon, an area having the orientation difference of equal to or greater illan 15' and an equivalent circle diameter of equal to or greater than 0.3 pm was defined as grain, an average intragranular orientation difference of the grains was calculated, and the ratio of the grains having the intragranular orientation diierence in a range of 5" to 14' was obtained. The grain defined as described above and the average intrapular orientation difference can be calc111ated using soflware "OM Analysis (trademark)" attached lo an EBSD analyzer. Tbe results are indicated in Table 3. In T&le 3, the structure other tlian ferrite, bainite, and martensite was pearlite or residual austelite. In addition, regarding Test No.5 1, since cracking occurred during the rolling, it was not possible to conduct the subsequent test. [0066] Next, in the te~isilete sl, the tensile strengtb and elongation were obtained. In the present invention, the tensile strength properties (tensile stsength (TS) and elongation (El)) among the mechanical properties were evaluated based on JIS Z 2241 (2011) using a tesl piece No. 5 of JIS Z 2241 (201 1) which was collected in iIte longitudinal direction which is orthogonal to the rolling direction at a 114W position or 314W position in the sheet width. As a result of the test, when TS was equal to or seater than 540 MPa, it was detennined tliai the strength was sufficien?, and when TS x El was equal to or g~ealetrh an 13500 MPa.o/b, it was deterininedthat the ductil~ty was sufficieilt. The results are indicated in Table 4. [0067] Next, the maximum fomng height was obtained tlxough the saddle type stretch flange test. In addition, a product of tensile strength (MPa) and maximum forming height (nun) was evaluated as an index of the stretch Bangeability, and in a case where the product is equal to or greater than 19500 numMPa, it is determined that the steel sheet was excelleilt in Ule stretch flangeability. The saddle type stretch flange test was conducted by setting a clearance at the time of puilchmg a corner portion to be 11% with a saddle-type formed producf as shown in FIG 2 in which a radius of curvature R of a corner was set to 60 mm, and an opening angle 6 was set to 1209 In addition, the existence of €he cracks haviug a length of 1/3 of the sheet were visually observed after forming, andthen a forming height of the limit in which the cracks were not present was determined as the maximum forn~ingheight The results are indicated in Table 4. [0068] Next, in order to evaluate the notch fatigue properties in the direction ortl~ogonatlo the rolling direction, a fatigue test was conducted by collectiilg the fatigue test pieces hrined illto a shape as showii in FIG 3 such that the direction orthogonal to the rolling direction from the same position as the position where tensile test pieces are collected becomes a long side. Tlic iBtigue test pieces sliown in FIG 3 are notch test pieces manufactured in order to obtain the fatigue strength of the notched material. The fatigue test pieces were ground to a depth of about 0.05 mm from the outermost layer. A stses~co ntrol axial fatigue test was conducted uiidct the conditions of sbess ratio I< = 0.1 and a frequencq of5 Hz, the stress wluch was not broken after 10 million cycles was defined as notched fatigue limit (FL) and the notch fatigue properties were evaluated. As a result of test, in a case where the relationship of FWTS 2 0.25 was satisfied, it is determined that the notch fatigue propelties were excellent. The results are indicated in Table 4. [0069] Next, the chemical convertibility and the corrosion resistance after coating were evaluated. Specificallj: frst, the manufactured steel sheet was performed pickling, aAer this axe steel sheet was subjected to a phosphate chemical conversion treatment so as to adhere a zinc phosphate coated film of 2.5 g/m2, and at this stage, measurement of existence of "SUKE" and a P ratio was performed as the evaluation the chemical convertibility. The " S U E mean the portions on which the chemical conversion coated film is not adhered, and the I) d o is a value indicated by PYP + H), which is a ratio of X-ray diffraction illtensity P of a phosphofilite (100) plane to X-ray diffraction intensity I-$ of a Hopiie (020) plane, measured using an X-ray diffraction apparatus. [0070] The phosphate cheinical conversion treatment is a treatment in which chemical solutions such as a phosphoric acid and Zn ions are used as main components, and is a chemical reaction to produce crystals called phospl~ofilite( FeZnl(P04)z. 4Hz0) between Fe ions eluted from the steel sheet and the chemical soluiioi~s. In addition, technical po~niso f the phosphate chenncdl coil~~elsiotrnea tment are as follows: (1) Fe ions are eluted so as to promote the read, and (2) Phosphofilite n ystals are formed densely on the surface ofthe steel sheet. Particularly, regarding (I), when oxides lesulting froin the formation of the Si scale remain on the surface of the steel sheet, since the elution of Fe is hindered, portions where the con~7etslonc oated film is not adhered called SUKE appear. Thus, an abnormal cheinical conversion coated film which is not supposed to be fonned on an iron surface called Hopite: Zn3(P04)2 . 4H20 may be formed and the performance aflcr coating deteriorates. Accordingly, it is important to make the surface normal such that Fe onthe surface ofthe steel sheet is eluted by phosphoric acid and thus Fe ions are sufficiently supplied. [0071] The existence of the "SUKE" (non-coated portion) was determined through the observation using a scanning electron microscope. Specifically, the observation was performed at a nlagnification of 1,000-fold in about 20 visual fields, and a case whese the mated film was evenly adhered to the entire surface and the "SUKE" (noncoated portions) Were not confinned is evaluated as "A" (none). In addition, a case whese the visual fields in u hich the "SUKE"(noii-coated portions) were confirmed were equal to or less than 5% is evaluated as " B (slightly confirmed). A case where the visual fields in which the "SUIW (non-coated portions) were conf~nledw ere greater than 5% is evaluated as "e" (exist). In the case of C, it was determined that the chemical converiibility was deteriorated. 100721 On the other hand, ihe Pratio can be measured using the X-ray dlffraction apparatus. The ratio of X-ray diffraction intensll?/ P of the phosphofilite (I 00) plane to tlie X-ray diffraction intensity H of Hopite (020) plane was obtained and evaluated as P ratio = P/(P + H). The P ratio indicates a proportion of hoplie and phosphofilite ill the coated film obtaincd through the chemical convetsion, and thus as hlghe~th e P ratio, the inore the phosphofilite, which means ihc phosphofilite crystals aie densely formed on the surface ofihe steel sheet. Typically, a relationship of P ratio 2 0.80 is required in order to satisfy the corrosion resistance performance and the coating performance, and in the corrosion strict environment such as a snow melting salt spray area, arelationship of P ratio 2 0.85 is required. Accordingly, when the P ratio is less U m l O 80, it was determined that the chemical convertibility was deteriorated The results are indicated in Table 4. [0073] Next, the corrosion resistance after coating was evaluated using the ibllowing methods. Firsf the electrodeposition coating (tlCckness of 25 bm) was performed on the steel sheet after the chemical conversion, a coating and baking treatment was perforllled at 170°C for 20 mifiutes, the electrodeposition coated film was cut wit11 a sharp-pointed knife with a cut of 130 nun in length until it reached the base steel (base metal) In addition, 5% of salt spray was continuously performed on the steel sheet at a temperature of 35°C for 700 hours under the salt spray conditions described in JIS Z 2371. After salt spray, a tape having a width of24 min (Nichiban 405 A-24 JIS Z 1522) was stuck on the notch portion in a length of 130 mn in parallel to the notch portion, and the maximum coat peeling width when the tape was peeled off was measured. When the ~namnumco at peeling width is greater than 4.0 mm, it mias determined that the corrosion resistance after coai~iig\? ?asd egraded. The results are md~catedin Table 4. 100741 [Table 31 [0075] [Table 41 As apparent from the results of Tables 3 and 4, In a case where the chemical composition defined in the plesent invention was hot-rolled under the preferable conditions (Test Nos.1 to 32), it was possible to obtain a high-strength hot-rolled steel sheet which is excellent in &etch flangeability, the co~rosionre sistance afier coating, and the notch fitigue properties, in which the strength is equal to or greater than 540 MPa, and an index of the stretch flangeability is equal to or greater than 19500 mmMPa, TS x El is 13500 MPa.%, and a relationship of FUTS 2 0.25 is satisfied, and a maxi~numc oat peeling width is 4.0 mn. On the other hand, Test Nos. 34 to 39,41, and 43 are examples in which the manufacturing conditions were deviated &om a preferable range, and thus any one or boih acthe structure obsenied wing the optical microscope and the ratio ofthe p i n s l~avingthein tragranular orienliation difference in a range of 5" to li(O did not satisfy the range of the present invention. In these examples, any one of the ductility, the stretch flangeability, and the notch Mgue properties did not satisfy the target value. In addition, since Test Nos. 44 to 57 are examples in whichthe chemical composition was outside the range of the present invention, any one of the strengik the ductility, the stretch flangeability, and the notch fatigue properties did not satisfy the target value. [Industrial Applicability] 100771 According to the p~ eseilt inveiliiou, it is possible to provide a higi-strength hot-rolled steel sheet which has high strength and is excellent in the strict stretch flailgeability, the notch fatigue properties, and the ccorros~otrle sistance after coatlng The steel sheet contributes to implovulg fuel econoilly of vehicles, and thus has high industrial applicability. CLAIMS What is claimed is. 1. A hot-rolled steel sheet comprising, as a chemical composition, by mass%, C: 0.020% to 0.070%, Mn: 0.60% to 2.00%, A: 0.10% to 1.00%, Ti: 0.015% to 0.170%, Nb: 0.005% to 0.0500/q. Cr: 0% to 1.0%, V: 0% to 0.300% Cu: 0% to 2.00% Ni: 0% to 2.00% Mo: 0Yo to 1.00%, Mg: 0% to 0.0100%, Ca: 0% to 0.0100%, REM: 0% to 0.1000%, 13: 0% to 0.0100%, Si: linlitedto equal to or less tl~an0 .100%, P: limited to equal to or less than 0.050%, S limited to equal to or less than 0.005%, and N: limited to equal to or less thm 0.006096, with the remainde~ of Fe and impurities; and wherein a structure includes, by an area ratio, ferrite and bainite 111 a range of 80% lo 98% 111 toial, and madensite in a range of 2% to lo%, and wherein in the structure, in a case %;here a bouudaty having an orieiitation difference of equal to or greater than 15" is defined as a grain boundary, and an area whch 1s surrounded by the grain boundary, and has an equivalent circle diameter of equal to or greater than0.3 pnl is defined as a grain, the ratio of the grains having an mtragranular orientation difference in a range of 5" to 14' is, by the area ratio, in a range of 10% to 60%. 2. The hot-rolled steel sheet according to Claim 1, wherein tlle cl~emicacl omposition contains, by mass%, one or two or more of V: 0.010% to 0.300%, Cu: 0.01% to 1.20'36, Ni: 0.01% to 0.60%, and Mo: 0.01% to 1.00%. 3. The hot-rolled steel sheet according to C!aim 1 or 2, wherein the chemical composition contains, by mass%, one or two or more of Mg: 0.0005%to 0.01000/0, Ca: 0.0005% to 0.0100%, and REM: 0.0005%to 0.1000%, 4. The hot-rolled steel sheet according to ally one of Claims 1 to 3, wherein the chemical composition contains, by mass%, B: 0.0002% to 0.0020%. 5. The hot-rolled steel sheet according lo nny one of Claims 1 to 4, wherein a tensile strength is equal to or greater than 540 MPa, and a product of the tensile strength and a maxirnuln forming height in a saddle type stretch flange test is equal to or greater than 19500 mmMPa.