Art
[1]
The present invention relates to an austenitic stainless steel, and relates to a production method thereof, more specifically, workability and surface properties are excellent austenitic stainless steel and a method.
BACKGROUND
[2]
The present invention relates to a stainless steel that is used in the sink or the like, more particularly to a projection on the surface after processing does not defects such as cracks or the like occurring after processing according as the sync process, workability and the surface of the surface defect of streaks, etc. do not occur this characteristic relates to the quality austenitic stainless steel.
[3]
Sink Bowl Kitchen Sink are generally made of stainless steel is used. It is mainly used by a specific general-purpose stainless steel, a shape of a typical sink bowl has no problem in forming a piece which is widely used.
[4]
However, an attempt to design the sink bowl recent variety of complex shapes in order to strengthen the competitiveness of the market has been increased.
[5]
Nitro-based austenite stainless steel material poor formability in steel molding generates defects such as cracks after the processing. There is also a case where a bad surface property being a projection formed on the surface, etc. after processing. It may cause a drop in the production yield in the working poor that when defects such as cracks, and requires additional processes such as polishing of the surface Poor surface characteristics arises a problem of increasing the cost of production.
[6]
For example a type of steel is widely used for processing of a sink, such as the prior art, the STS 304 steel, but the above-described processing cracks and surface deterioration acts as a persistent problem which often occurs.
[7]
[Patent Document 1] Korea Patent Laid-Open Publication No. 10-2013-0014069 No. (2013.02.06. Public)
Detailed Description of the Invention
SUMMARY
[8]
Embodiments of the present invention, even if processed into a complicated shape such as a sink to provide a machining cracks and surface deterioration does not occur and processability surface properties excellent in austenitic stainless steel and a method.
Problem solving means
[9]
Formability and surface properties are excellent austenitic stainless steel according to one embodiment of the present invention is, in weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, the rest is in the range of Fe and unavoidable impurities, and containing, the part piece to the surface stones of Ni, which is defined by the formula (1) from 0.6 to 0.9.
[10]
(C -Min ) / (C -Ave ) ...... 식 (1)
[11]
Here, C Ni -Min is the minimum concentration of Ni in the surface, C Ni -Ave is the average Ni concentration at the surface.
[12]
Further, according to one embodiment of the present invention, Mo: 0.01 to 0.2%, Cu: it may further include 0.1 to 4.0%.
[13]
Further, according to one embodiment of the invention, the formula (2) Ni surface side monument, defined as may be in the range of 1.1 to 1.6.
[14]
(C Ni -Max ) / (C Ni -Min ) ... ... Formula (2)
[15]
Here, C Ni -Max is the maximum concentration of Ni in the surface, C Ni -Ave is a minimum concentration of Ni in the surface.
[16]
Further, according to one embodiment of the present invention, is less than 60% of Ni surface side seokbu the area fraction, Ni surface part piece seokbu may be greater than 5% in area fraction.
[17]
Further, according to one embodiment of the present invention, the Ni surface side seokbu is large Ni concentrated area than Ni average concentration at the surface of the Ni surface part piece seokbu may be a small Ni depletion region than Ni average concentration at the surface .
[18]
Further, according to one embodiment of the present invention, the Ni thickened area has more than 1.2 times the Ni concentration than the Ni average concentration at the surface of the Ni-deficient region is a Ni concentration of up to 0.8 times the Ni average concentration at the surface It may have.
[19]
Further, according to one embodiment of the present invention, the Ni surface seokbu part piece may include a long diameter of not less than 100㎛ segregation more than 60%.
[20]
Further, according to one embodiment of the present invention, it may be a work-hardening rate (H) is in the range 1,500 to 3,000 MPa in the binary strain range of 0.1 to 0.3.
[21]
Further, according to one embodiment of the present invention, it is possible to have more than 60% elongation.
[22]
Formability and surface properties are excellent austenitic stainless steel manufacturing method according to an embodiment of the present invention is, in weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, the remainder comprising a continuous casting austenitic stainless steel which comprises Fe and inevitable impurities.
[23]
The continuous casting step is, 2 of the car cooling zone, 1,150 to 1,200 ℃ of claim the slab in step 900 to 1,150 ℃ in a second temperature range for cooling the slab from the first temperature range by more than 60 ℃ / min rate 10 ℃ / the slab in steps and not more than 900 ℃ third temperature range at a rate of cooling of the min or less and a step of cooling of at least 20 ℃ / min rate.
[24]
Further, according to one embodiment of the present invention, it may include steps of cold rolling the hot rolled slab to hot rolling the slab cooling in the secondary cooling stage.
[25]
Further, according to one embodiment of the present invention, it can be re-heated within 5 hours of the time of hot rolling and continuous casting of austenitic stainless steel slabs.
[26]
Further, after According to one embodiment of the invention, annealing the hot-rolled or cold-rolled and annealed hours, raising the temperature to the annealing temperature of 1,000 to 1,200 ℃ less than 30 seconds, the holding time may be 30 seconds.
Effects of the Invention
[27]
Even though improving the austenitic stainless steel is, workability in accordance with embodiments of the present invention processed into complicated shapes as sinks, etc. it is possible to prevent defects such as processing crack, a surface of a projection to streaks generated on the surface after processing it is possible to prevent the failure.
Brief Description of the Drawings
[28]
Figure 1 is a photo photographed the Ni piece seokbu seokbu and part piece are formed on the surface of austenitic stainless steel according to one embodiment of the present invention.
[29]
Figure 2 is a picture taken with a conventional austenitic stainless steel surface after machining.
[30]
3 is a photograph taken after machining austenitic stainless steel surface, according to one embodiment of the present invention.
[31]
Figure 4 is a picture taking a austenitic stainless steel surface after processing according to the comparative example of the present invention.
[32]
Figure 5 is a picture taking a sink processing a processing surface with a conventional austenitic stainless steel.
[33]
Figure 6 is a picture taking a processed surface processed in a sink austenitic stainless steel according to one embodiment of the present invention.
[34]
7 is a graph illustrating a method for manufacturing austenitic stainless steel according to one embodiment of the present invention.
Best Mode for Carrying Out the Invention
[35]
Formability and surface properties are excellent austenitic stainless steel according to one embodiment of the present invention is, in weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, the rest is in the range of Fe and unavoidable impurities, and containing, the part piece to the surface stones of Ni, which is defined by the formula (1) from 0.6 to 0.9.
[36]
(C -Min ) / (C -Ave ) ...... 식 (1)
[37]
Here, C Ni -Min is the minimum concentration of Ni in the surface, C Ni -Ave is the average Ni concentration at the surface.
Mode for the Invention
[38]
Hereinafter will be described in detail with reference to the accompanying drawings, an embodiment of the present invention. The following examples will be presented to fully convey the scope of the invention to those of ordinary skill in the art. The present invention is not limited to the embodiments described herein may be embodied in different forms. Figures may be somewhat exaggerated to express the size of the components, for clarity, not shown, and a portion not related to the description in order to clarify the invention.
[39]
One formability and surface properties are excellent austenitic stainless steel according to an embodiment of the present invention is, in weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, and the remainder including Fe and inevitable impurities. Further, in addition, Mo: may further include 0.1 to 4.0%: 0.01 to 0.2%, Cu.
[40]
In the following, a description will be given of the reason for numerical limitation of the components constituting the formability and surface properties are excellent austenitic stainless steel of the present invention.
[41]
C is added to adjust within a range from 0.005 to 0.15% by weight.
[42]
C is the austenite phase is the more stable austenite phase is added as a stabilizing element containing one or more than 0.005%, if excessively contained, because the strength can be difficult to over-higher processing is limited to not more than 0.15%.
[43]
Si is added to adjust within a range of 0.1 to 1.0% by weight.
[44]
Si is added more they provide the effect of a certain level of work hardening and corrosion resistance containing one, adding too much over 0.1%, it is possible to inhibit the toughness will be limited to less than 1.0%.
[45]
Mn is added to adjust within a range of 0.1 to 2.0% by weight.
[46]
Mn is limited to 2.0% or less because the corrosion inhibition when austenite phase to stabilize the more is added as an austenite stabilizing element, and the excessive addition of one, less than 0.1% it is effective to reduce the work hardening rate.
[47]
Ni is added to adjusted within 6.0 to 10.5% by weight.
[48]
Ni are austenite addition of nitro onto the more added as a stabilizing element and stabilizes austenite phase has the effect that the addition amount increases and the austenite reducing the river softening and work hardening rate, because it is an element that forms a part seokdae in the present invention at least 6.0% One, if you added a lot of leads to increase in cost, so is limited to 10.5%.
[49]
Cr is added by controlled within 16 to 20% by weight.
[50]
Cr is one containing more than 16% as an element for improving the corrosion resistance, since the excessive addition is accompanied by an increase in cost will be limited to 20%.
[51]
N is added to adjust within a range from 0.005 to 0.2% by weight.
[52]
N is the more austenite phase is added as a stabilizing element to stabilize austenite phase to improve corrosion resistance, because one contains not less than 0.005%, if excessively contained, the strength may be difficult to process because excessively increased is limited to 0.2% or less.
[53]
Mo: is added to adjust within a range of 0.01 to 0.2% by weight.
[54]
Mo has got the effect of improving the corrosion resistance and workability containing one or not less than 0.01%, since the excessive addition is accompanied by an increase in cost will be limited to less than 0.2%.
[55]
Cu: The addition of the controlled within 0.1 to 4.0% by weight.
[56]
Cu are austenite phase to stabilize the more added as a stabilizing element austenite phase, and it is effective to reduce the softening and work hardening rate Austenitic Steels and less than 0.1%, the amount added is contained to increase the austenite phase to stabilize in the present invention this characteristic is obtained in pursuit can be added even 4.0%. Preferably, however, excessive addition of Cu is therefore accompanied by an increase in cost will be limited to 2.0%.
[57]
Figure 1 is a photo photographed the Ni piece seokbu seokbu and part piece are formed on the surface of austenitic stainless steel according to one embodiment of the present invention. Figure 2 is a picture taken with a conventional austenitic stainless steel surface after machining. 3 is a photograph taken after machining austenitic stainless steel surface, according to one embodiment of the present invention.
[58]
1, the formability and surface properties are excellent austenitic stainless steel according to one embodiment of the present invention, a Ni piece seokbu and Ni seokbu part piece on the steel surface. The Ni surface side seokbu is large Ni concentrated area than the average concentration of Ni in the surface, the surface Ni seokbu part piece is a small Ni Ni depletion region than average concentration at the surface. The light-colored in Fig. 1 refers to the part piece seokbu Ni, and the dark color means a Ni piece seokbu.
[59]
Referring to Figure 2, a photograph taking a conventional austenitic stainless robust STS 301 river surface. This is a steel that is not formed with the austenitic stainless steel and Ni piece seokbu seokbu part piece of the river surface, the surface properties of the surface roughness shows a degraded by a projection on the surface during the processing thereof occurs.
[60]
When Alternatively, referring to Figure 3, a photograph taken austenitic stainless steel surface, according to one embodiment of the present invention. Which it is formed with austenitic stainless steel and Ni piece seokbu seokbu part piece to the surface, even if the part can be seen that the surface has a graceful quality without causing a stripe or protrusions on the surface.
[61]
The present inventors with respect to this effect when machining a stainless steel, a Ni piece seokbu formed, the formation of the martensitic transformation is much composed of projections in the part piece seokbu during processing in case the material also contains the same amount of Ni does not form a part seokbu It estimates that this inhibition.
[62]
That is, one embodiment of the austenitic stainless steel is the surface of the Ni Tin part piece, which is defined by the following formula (1) according to the present invention is in the range of 0.6 to 0.9.
[63]
(C -Min ) / (C -Ave ) ...... 식 (1)
[64]
Here, C Ni -Min is the minimum concentration of Ni in the surface, C Ni -Ave is the average Ni concentration at the surface.
[65]
Tin surface part piece of Ni is defined by the formula (1), a value obtained by dividing the minimum concentration of Ni in the steel surface in an average concentration of Ni, the minimum concentration of Ni is the measured value in the Ni seokbu part piece.
[66]
Figure 4 is a picture taking a austenitic stainless steel surface after processing according to the comparative example of the present invention.
[67]
If the surface of the part piece Tin Ni is less than 0.6, it is formed in the side seokdae excessively on the surface there is a problem in that severe streaking along the rolling direction on the surface after machining. 4, the surface part piece seats of the Ni in the recorded pictures of the surface after machining austenitic stainless steel having a 0.5, it can be seen that the stripes observed in the rolling direction, the surface defects caused by such streaks the need for additional processes such as polishing of the surface, thereby increasing the production cost.
[68]
Further, when the surface of the part piece Tin Ni is in excess of 0.9, the amount of small pieces and seokbu seokbu part piece is either not formed in the form of interest in the present invention does not achieve the martensitic transformation of the part piece seokbu.
[69]
That is, the austenitic stainless steel according to one embodiment of the present invention is the Ni surface side monument to be defined by the following formula (2) in the range of 1.1 to 1.6.
[70]
(C Ni -Max ) / (C Ni -Min ) ... ... Formula (2)
[71]
Here, C Ni -Max is the maximum concentration of Ni in the surface, C Ni -Ave is a minimum concentration of Ni in the surface.
[72]
If the Ni surface side monument is less than 1.1, the amount of small pieces and seokbu seokbu part piece is either not formed in the form of interest in the present invention does not achieve the martensitic transformation of the part piece seokbu.
[73]
Further, the Ni surface side when the monument of 1.6 is exceeded, is formed in the side seokdae excessively on the surface appears severe streaks along the rolling direction on the surface after machining, the surface defects caused by such streaks is required for further processing, such as polishing of the surface by thus increasing the production cost.
[74]
That is, one wherein the austenitic stainless steel is the Ni surface side seokbu according to an embodiment of the present invention is less than 60% in area fraction, the Ni surface part piece seokbu may be greater than 5% in area fraction.
[75]
The Ni surface side seokbu is large Ni concentrated area than the average concentration of Ni in the surface, the surface Ni seokbu part piece is a small Ni Ni depletion region than average concentration at the surface. For example, the Ni thickening area has more than 1.2 times the Ni concentration than the average concentration of Ni in the surface, it said Ni-deficient region can have a Ni concentration of less than 0.8 times the mean concentration of Ni in the surface.
[76]
Such a Ni surface part piece or seokbu form the in the austenitic area fraction on the stainless steel surface to no more than 5%, the Ni surface side when seokbu is formed by more than 60% in area fraction, the processing when the Ni surface part piece a martensitic transformation from seokbu mothayeo sufficiently made difficult to suppress the projection on the surface after machining.
[77]
For example, the Ni surface seokbu part piece may include a long diameter of not less than 100㎛ segregation more than 60%. Accordingly, as the Ni surface part piece finely divided my seokbu segregation, as the segregation size is increased it is possible to prevent the streaks occur along the rolling direction on the surface after processing it is possible to improve the surface properties.
[78]
Further, the austenitic stainless steel according to one embodiment of the present invention may be in the work hardening rate (H) is in the range 1,500 to 3,000 MPa in the binary strain range of 0.1 to 0.3. Accordingly, the austenitic stainless steel according to one embodiment of the present invention may have an elongation of 60% or more.
[79]
The austenitic stainless steel can be excellent in the Ni surface side seokbu and workability to prepare a range of part piece with seokbu, true strain of 0.1 to 1,500 to 3,000 MPa the work hardening rate in the 0.3 range in the material formed on the surface . Jin can follow the bar to strain and the method of calculating the work hardening rate is widely defined in the academic world, called work hardening rate (H) in the present invention means the period given the work hardening rate (H) is calculated from the typical uniaxial tensile , that refers to the total of the average value in the range 0.1 to 0.3 strain Gene. This true strain is the work hardening rate (H) - as the value which is calculated as the slope of every moment from the true stress, severe is the value DAP topically, but be out of range of 1,500 to 3,000 MPa specified by the present invention As a result the material because it contributes to the characteristic mean value, the austenitic stainless steel shall satisfy the work hardening rate (H) in the range of 1,500 to 3,000 MPa in the binary strain range of 0.1 to 0.3.
[80]
Figure 5 is a picture taking a sink processing a processing surface with a conventional austenitic stainless steel. Figure 6 is a picture taking a processed surface processed in a sink austenitic stainless steel according to one embodiment of the present invention.
[81]
To cross the majority of the material, the strain range of 0.1 to 0.3 interval binary during processing, and a crack as shown in the example of processing the Fig difficult by the excessive hardening in the case of work-hardening than the speed 3,000 MPa material occurs in this region. In this case, workability is a representative indicator of the elongation can be seen that has a less than 60%. As to satisfy the well, the work hardening rate is less than 1,500 MPa in an elongation is 60% or more is preferably limited because of a problem that wrinkles occur one, according to the excessive softening of the material. Thus, the material prepared from the scope of the present invention has been proposed is found to be excellent in workability sink, as in the example of FIG.
[82]
7 is a graph illustrating a method for manufacturing austenitic stainless steel according to one embodiment of the present invention.
[83]
Formability and surface properties are excellent austenitic stainless steel manufacturing method according to an embodiment of the present invention is, in weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, the remainder comprising a continuous casting austenitic stainless steel which comprises Fe and inevitable impurities.
[84]
Of 7, wherein in the continuous casting step is the step of cooling in the secondary cooling zone, a cast steel from 1,150 to 1,200 ℃ the first temperature range by more than 60 ℃ / min speed, 900 to 1,150 ℃ claim 2 is a slab at a temperature range of slab in the step of cooling at a rate of less than 10 ℃ / min and not more than 900 ℃ third temperature range comprising the step of cooling of at least 20 ℃ / min rate.
[85]
The continuously cast slab is subjected to a step of cooling the cast slab to at least 60 ℃ / min rate at a first temperature range of 1,150 to 1,200 ℃.
[86]
To the continuous casting from the molten steel having a component system of the present invention produced a slab, in this case to form the Ni surface side seokbu and Ni surface part piece seokbu on the cast surface in the first temperature range and performs the cast quenched . In this case, for example, it is done by a cast full face through the front nozzle spray to cool rapidly. If Alternatively, the main side on which the first cooling at a rate of less than 60 ℃ / min in the first temperature range may not be formed in the Ni surface side seokbu and seokbu part piece to the surface.
[87]
Typically, but known seat Ni segregation cast center part of the continuous casting, when performing rapid cooling at a constant temperature intervals as in the present invention, it is possible to form the Ni segregation in the slab surface.
[88]
Accordingly, the austenitic stainless steel according to one embodiment of the present invention, the surface part piece seats of Ni represented by the formula (1) satisfies the range of 0.6 to 0.9, Ni surface represented by the formula (2) the monument side may satisfy the range of 1.1 to 1.6.
[89]
Thereafter, go through the step of cooling the cast steel at a second temperature range of 900 to 1,150 ℃ at a rate of less than 10 ℃ / min.
[90]
In the first after the formation of the Ni segregation to the surface at a temperature interval, wherein the second temperature ranges to perform slow cooling convenience the state. Accordingly, some of the Ni segregation of the slab surface is to be re-employed.
[91]
Accordingly, the austenitic stainless steel work piece seokbu Ni surface in accordance with an embodiment of the present invention is less than 60% in area fraction, Ni surface part piece seokbu may satisfy more than 5% in area fraction.
[92]
Thereafter, go through the step of cooling the cast steel at not more than 900 ℃ third temperature range of at least 20 ℃ / min rate.
[93]
In the first re-employed after the Ni segregation part to the surface in the second temperature range, wherein the third temperature interval and performs the rapid cooling the cast. Accordingly, it is possible to refine the segregation in the Ni surface seokbu part piece of the product surface.
[94]
Accordingly, the Ni surface seokbu part piece may include a long diameter of not less than 100㎛ segregation more than 60%.
[95]
Formability and surface properties are excellent austenitic stainless steel manufacturing method according to an embodiment of the present invention, including the steps of cold rolling the hot rolled slab to hot rolling, the cooled slab in a secondary cooling step do.
[96]
At this time, the re-heating is performed within five hours of hot rolling during continuous casting of austenitic stainless steel slabs. When the re-heating time of the slab for more than five hours, the formed on the surface of Ni surface side seokbu and part piece not seokbu can begins to decompose satisfy the Ni surface part piece seokbu and the Ni surface side monument on the surface of interest in the present invention do.
[97]
In addition, after annealing the hot-rolled or cold-rolled and annealed hours, raising the temperature to the annealing temperature of 1,000 to 1,200 ℃ less than 30 seconds, the holding time is carried out within 30 seconds. When hot-rolled and annealed or cold-rolled and annealed with increasing the temperature rising time and holding time, that the Ni surface side seokbu and part piece seokbu formed on the surface starts to be decomposed by the Ni surface part piece seokbu and the Ni surface side monument on the surface of interest in the present invention It can not be satisfied.
[98]
[99]
The present invention through the following examples to be described in more detail.
[100]
Example
[101]
To an austenitic stainless steel slab containing Examples 1 to 9, and the components of the Comparative Examples 1 to 6 shown in Table 1 were prepared by continuous casting. Then, after the cold rolling to the hot-rolling, and a total rolling reduction of 50% to prepare a cold-rolled steel sheet.
[102]
TABLE 1
division C And Mn Ni Cr With you N
Examples 1 0.115 0.6 0.2 6.8 17.3 0.61 0.19 0.05
To honor two 0.109 0.6 0.8 6.7 17.2 0.59 0.14 0.05
To honor 3 0.108 0.2 1.6 6.7 17.2 1.00 0.09 0.05
To honor four 0.108 0.9 1.9 6.7 16.2 1.60 0.09 0.05
To honor five 0.108 0.6 0.9 9.8 19.6 1.00 0.09 0.05
To honor 6 0.108 0.6 1.0 6.6 17.2 0.12 0.04 0.04
To honor 7 0.009 0.6 0.9 6.6 17.2 2.05 0.04 0.14
To honor eight 0.115 0.6 0.9 6.6 17.2 2.94 0.04 0.04
To honor nine 0.115 0.6 0.9 6.1 17.2 3.90 0.01 0.04
Comparative Example 1 0.110 0.6 0.9 6.7 17.0 0.25 0.12 0.04
Comparative Example 2 0.113 0.6 0.9 6.7 17.2 0.00 0.04 0.04
Comparative Example 3 0.110 0.6 0.8 6.6 17.2 0.05 0.04 0.04
Comparative Example 4 0.115 0.6 0.9 5.8 17.2 1.00 0.01 0.04
Comparative Example 5 0.111 0.6 0.9 7.0 18.0 0.01 0.04 0.04
Comparative Example 6 0.060 0.6 0.9 8.5 19.2 0.01 0.01 0.04

[103]
Accordingly, Ni surface of the prepared cold-rolled steel sheet part piece stones, pieces are shown in the monument, segregation size and distribution, and after processing the surface properties and the processing after the test of the steel plate to observe whether cracks to wrinkles caused by the naked eye Table 2.
[104]
TABLE 2
division Ni surface part piece Tin Ni surface side monument Part piece seokbu internal diameter 100㎛ less segregation bunporyang (%) Surface Properties Workability
Examples 1 0.90 1.1 90 Good Good
To honor two 0.67 1.5 65 Good Good
To honor 3 0.90 1.1 90 Good Good
To honor four 0.63 1.6 65 Good Good
To honor five 0.71 1.4 70 Good Good
To honor 6 0.67 1.5 65 Good Good
To honor 7 0.83 1.2 85 Good Good
To honor eight 0.90 1.1 90 Good Good
To honor nine 0.90 1.1 90 Good Good
Comparative Example 1 0.53 1.9 55 stripe crack
Comparative Example 2 0.59 1.7 60 stripe crack
Comparative Example 3 0.56 1.8 55 stripe crack
Comparative Example 4 0.45 2.2 45 stripe crack
Comparative Example 5 1.00 1.0 - spin wrinkle
Comparative Example 6 1.00 1.0 - spin wrinkle

[105]
Where Ni surface part piece stones and pieces monument is measured from the surface of austenitic stainless steel, the measuring surfaces are surfaces made of a rolling direction and a width in the axial direction, that corresponds to the face is often referred to as a rolling surface. The length of each axis in order to have a statistically significant is the least 500㎛ and measured over 50 locations at equal intervals in each axis. Method of measurement was taken of the Ni element distribution by EPMA method one can safely utilize that any such energy dispersive spectroscopy (EDS), or electron probe micro analysis (EPMA), 800㎛ * 800㎛ area. Stainless steel is generally so to form a layer on the surface was measured in a reaction volume as the device can have when it is not sufficient 200㎛ the oxide to 1 from the surface to be polished to measure the area of ​​the oxide layer below surface which measures the element. In addition, foreign matter is nonoe of the present invention was that of the base metal Ni segregation.
[106]
Referring to Table 1 and Table 2, when satisfying the austenitic stainless steel components and scope in accordance with one embodiment of the present invention, it can be seen that the surface properties and excellent formability. However, the processability surface properties to be seen in order to open the case, even if these components satisfy the ranges that do not meet the seats Ni part piece of the steel surface to side monument.
[107]
In addition, we performed further experiments to determine the relationship between the additional work hardening rate (H) and the sink workability. In this way, was performed with the sync process using the prepared cold-rolled steel sheet, this time, was measured the work hardening rate and elongation of the steel sheet, after processing to observe whether cracks to wrinkles caused by the naked eye are shown in Table 3 below.
[108]
TABLE 3
division Work hardening rate (H) Elongation (%) Sink processability
Examples 1 2990 60.8 Good
To honor two 2462 65.5 Good
To honor 3 1979 67.0 Good
Comparative Example 1 4684 47.4 crack
Comparative Example 2 3747 53.7 crack
Comparative Example 3 1474 64.8 wrinkle
Comparative Example 4 1372 64.6 wrinkle

[109]
Therefore, the sink workability is excellent and seen that cracks on the surface after machining to wrinkles austenitic stainless steel does not occur is produced so as to satisfy the work hardening rate (H) in the range of 1,500 to 3,000 MPa in the binary strain of 0.1 to 0.3 range can.
[110]
In the above-described bar, although the description has been made to exemplary embodiments of the present invention, in the present invention is not limited to those skilled in the art without departing from the spirit and scope of the claims set forth in the following it will be appreciated from the various changes and modifications are possible.
Industrial Applicability
[111]
Formability and surface properties are excellent austenitic stainless steel in accordance with embodiments of the present invention is applicable in applications such as sink bowls of kitchen sinks.
[112]

Claims
[Claim 1]
By weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, and the remainder Fe and includes unavoidable impurities, the following equation (1) is excellent in the surface part piece Tin Ni is 0.6 to 0.9 range in workability and surface properties of which is defined as an austenitic stainless steel. (C Ni -Min ) / (C Ni -Ave ) ... ... Formula (1) where, C Ni -Min is the minimum concentration of Ni in the surface, C Ni -Ave is the average Ni concentration at the surface.
[Claim 2]
Claim 1 wherein, Mo in the range of 0.01 to 0.2%, Cu: is excellent in workability and surface properties, which further comprises 0.1 to 4.0%, an austenitic stainless steel.
[Claim 3]
According to claim 1, wherein the following formula (2) is excellent austenitic stainless steel Ni surface side monument is from 1.1 to the range of workability and surface properties of 1.6 as defined by the. (C Ni -Max ) / (C Ni -Min ) ... ... Equation (2) where, C Ni -Max is the maximum concentration of Ni in the surface, C Ni -Ave is a minimum concentration of Ni in the surface.
[Claim 4]
According to claim 1, Ni surface side seokbu is less than 60% in area fraction, Ni surface part piece seokbu is excellent in the workability and surface properties more than 5% in an area fraction of austenitic stainless steel.
[Claim 5]
The method of claim 4, wherein the Ni surface side seokbu is large Ni concentrated area than Ni average concentration at the surface of the Ni surface part piece seokbu is superior in Ni small Ni-deficient region in workability and surface properties than the average concentration of the surface austenite Night series stainless steel.
[Claim 6]
The method of claim 5, wherein the Ni thickened area has more than 1.2 times the Ni concentration than the Ni average concentration at the surface of the Ni-deficient region workability and surface properties having a Ni concentration of up to 0.8 times the Ni average concentration at the surface this excellent austenitic stainless steel.
[Claim 7]
4 wherein the Ni surface part piece seokbu the formability and surface properties are excellent austenitic stainless steel for a long diameter of not including 100㎛ less segregation than 60% on.
[Claim 8]
According to claim 1, wherein the true strain of 0.1 to 0.3 range work hardening rate (H) is a range of from 1,500 to excellent processability and surface properties of 3,000 MPa austenitic stainless steel in the.
[Claim 9]
According to claim 8, excellent in workability and surface properties having an elongation of 60% or austenitic stainless steel.
[Claim 10]
By weight%, C: 0.005 to 0.15%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.0%, Ni: 6.0 to 10.5%, Cr: 16 to 20%, N: 0.005 to 0.2%, and the remainder Fe and an austenitic stainless steel containing incidental impurities comprising the steps of continuous casting, the above continuous casting step, a secondary cooling zone, a cast steel from 1,150 to 1,200 ℃ the first temperature range by more than 60 ℃ / min speed the step of cooling; A cast steel from 900 to 1,150 ℃ in a second temperature range further comprising: cooling at a rate of less than 10 ℃ / min; And not more than 900 ℃ the formability and surface properties are excellent method of manufacturing an austenitic stainless steel comprising the step of cooling of at least a cast steel in the temperature range 20 ℃ 3 / min speed.
[Claim 11]
The method of claim 10, further comprising: hot rolling the slab cooling in the secondary cooling step; And processability and surface properties are excellent process for producing austenitic stainless steel, comprising cold rolling the hot rolled slab.
[Claim 12]
The method of claim 11, wherein during hot-rolling, continuous casting of an austenitic stainless steel formability and surface properties are excellent method of producing an austenitic stainless steel reheating within five hours of the slab.
[Claim 13]
According, annealing the hot-rolled or cold-rolled and annealed when, after raising the temperature to the annealing temperature of 1,000 to 1,200 ℃ of less than 30 seconds, the holding time is the processability and surface properties are excellent method for producing austenitic stainless steel less than 30 seconds to claim 11.