Art
[1]
The present invention is a ferritic stainless steel, and relates to a production method thereof, and more particularly, to satisfy the properties required for automobile exhaust system heat and condensate corrosion is improved automotive exhaust system ferritic stainless steel and its relates to a process for the preparation for will be.
BACKGROUND
[2]
Of stainless steel, especially a ferritic stainless cold-rolled product has excellent high-temperature characteristics such as thermal expansion coefficient, the thermal fatigue property and resistance to stress corrosion cracking. Accordingly, ferritic stainless steel is widely used in automotive exhaust system components, household appliances, construction, household appliances, elevator.
[3]
In general, automobile exhaust system members are separated by a high-temperature member (Hot part) and the low-temperature member (Cold part) depending on the temperature of the exhaust gas. Auto parts of a high temperature member such as the manifold (Exhaust manifold), the converter (Converter) and a bellows (Bellows) etc., and use temperatures of these components are high-temperature strength mainly above 600 ℃, and thermal fatigue and high-temperature salt corrosion property It should be excellent. On the other hand, the member, such as a low-temperature member (Cold part) is a muffler for reducing the noise of the automobile, mainly the exhaust gas temperature within 400 ℃ (muffler) is sets. Automotive exhaust system low-temperature member (Cold part) is stainless steel, such as the outer surface balcheong corrosion properties according to condensate corrosion property, used in winter claim glossitis generated by the car sulfur (S) component in the fuel reasons (or STS) 409, 409L, 439, 436L or it has been used materials such as Al-coated stainless steel 409.
[4]
For example, stainless steel is the best STS 409L material of the steel may, and the primarily used for sensitizing the prevention and workability temperatures below 700 ℃ excellent grades of C, to stabilize the N to Ti weld to approximately 11% Cr car even against the condensate component generated in the exhaust system is the most widely used type of steel because it has less corrosion resistance.
[5]
And in a corrosive environment requiring corrosion resistance, and use of Cr 17 weight% of the STS 439 and STS 436L steel containing Mo about 1% by weight of the STS 439 steel, but has a problem that the material cost is raised parts.
[6]
Recent automotive production penetration in the case of countries such as China, Latin America, India, and rapidly growing, and the situation in the sulfur (S) content is extremely rich in comparison with other developed countries, while gasoline components. For example, Korea, in the case of Japanese, but defines a sulfur (S) content of the gasoline components to 10ppm or less, in the case of Chinese and defined by 500ppm or less, and has actually contain more sulfur (S) component in accordance with the area .
[7]
Sulfur of the gasoline component (S) component is a sulfate ion (SO of the condensed water components of automobile exhaust gas 4 2- , and concentrated to), pH is a strong sulfuric acid (H corrosion resistance of less than 2 2 SO 4 to form a) atmosphere, and thus the existing STS 409L is not possible to ensure corrosion resistance, and a progressively containing more than 17% by weight Mo or Cr component, such as the STS 439, 436L stainless steel and applying a material of chromium system. However, in the case of the material because a problem that the resource prices rise gradually, Cr, not adding an expensive element such as Mo or or Examples adding only a very small amount of an element instance, excellent pitting resistance than conventional Al-plated stainless 409 steel and the development of stainless steel material with corrosion in the condensate is required.
[8]
Patent Document 1: Republic of Korea Laid-Open Patent Publication No. 10-2008-0110662 No. (2008.12.18).
Detailed Description of the Invention
SUMMARY
[9]
Embodiments of the invention according to Sikkim form a coating compound at the interface between the base material and the plated layer to form a Al-plated layer on not only containing Sn in a ferritic stainless steel for automobile exhaust system and stainless steel to Sn thickening of the river surface, the base material to provide a heat-resistant and corrosion resistance such as ferritic stainless steel for automobile exhaust system, which can satisfy the properties required for automobile exhaust system of condensed water from the atmosphere.
[10]
In addition, embodiments of the present invention to provide a method for manufacturing a ferritic stainless steel for the automobile exhaust system.
Problem solving means
[11]
In ferritic stainless steel according to one embodiment of the present invention, in weight%, C: 0.01% or less, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5%, Sn: 0.03% to 0.5%, balance of Fe and other unavoidable stainless steel base metal and the aluminum coating layer formed on the stainless steel base material containing an impurity It includes.
[12]
(Al at the interface between the stainless steel base metal and the aluminum plating layer 19 FeMnSi 2 ) 5,31 comprises a compound coating containing (Aluminum Iron Manganese Silicide).
[13]
Further, according to one embodiment of the invention, the coating compound is Al 9 FeSi 2 (Aluminum Iron Silicon), Al 3 FeSi 2 more than one selected from the group consisting of (Aluminum Iron Silico), Al ( Aluminum) It can be included.
[14]
Further, according to one embodiment of the invention, the surface portion of the stainless steel base metal adjacent to the aluminum plating layer may be a Sn is concentrated at least 4.5 times compared to the stainless steel base material.
[15]
Further, according to one embodiment of the present invention, the Sn in the surface portion of the stainless steel base material can be concentrated from 4.5 to 6.1 times compared to the stainless steel base material.
[16]
Further, according to one embodiment of the present invention, Sn: it may comprise 0.05 to 0.5%.
[17]
Further, according to one embodiment of the present invention, when the condensate corrosion property evaluation (JASO-M611-92 B), a maximum depth of formula be up to 0.4mm.
[18]
Further, according to one embodiment of the invention, the surface color difference (△ E) before and after the heat treatment of stainless steel it may be 10 or less.
[19]
According to the method for manufacturing ferritic stainless steel according to one embodiment of the present invention, in weight%, C: 0.01% or less, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5%, Sn: 0.03% to 0.5%, remainder Fe and other unavoidable ferritic stainless steel containing impurities hot rolling, cold rolling, and It includes aluminum plating process.
[20]
Further, according to one embodiment of the present invention, the ferritic stainless steel can be manufactured in a conventional manufacturing process STS 409L.
[21]
Further, according to one embodiment of the invention, aluminum-plated the ferritic stainless steel comprising the step of heat treatment at a temperature of 300 to 500 ℃ within 48 hours more, the surface of the color difference (△ E) before and after the heat treatment is 10 or less can.
Effects of the Invention
[22]
Embodiments of the invention are the conventional ferritic stainless steels during the production of conventional 11Cr stainless steel robust cost without causing a cost increase and manufacturing drop of more than about 0.05% Sn was added to the STS 409, improving the heat resistance and resistance to condensate corrosion ferrite stainless steel can do.
[23]
In addition, when using a ferritic stainless steel in accordance with embodiments of the present invention used as such for the exhaust end parts such as mufflers related materials for automotive exhaust systems, without any existing high-sulfur fuel region manufacturing cost increase in the area, such as China It can be manufactured for the automotive exhaust system components to ensure excellent corrosion resistance.
Brief Description of the Drawings
[24]
Figure 1 is a graph showing the maximum depth of the formula in a stainless steel non-added stainless steel automotive exhaust system according to the present invention the addition of Sn condensate solution graph.
[25]
2 is a view illustrating results of analysis of the interface between the Al layer and the stainless steel the stainless steel base material was added to Sn of the invention in a transmission electron microscope (TEM) EDS (Energy-Dispersive Spectroscopy).
[26]
3 is a view illustrating results of analysis of transmission electron microscopy (TEM) EDS (Energy-Dispersive Spectroscopy) with a line (line) from stainless steel, Al-plated layer by the addition of Sn of the present invention to the base material.
[27]
4 is a graph showing the interface between the analysis of X-ray diffraction (XRD) with the addition of Sn of stainless steel, Al-plated layer and the stainless steel base material of the present invention.
[28]
5 is a view showing a line (line) analysis result of a transmission electron microscope (TEM) EDS (Energy-Dispersive Spectroscopy) from stainless steel, Al plating a non-addition of Sn to the base material.
[29]
Figure 6 is a graph illustrating results of analysis of the interface between the non-addition of the Sn-plated layer of stainless steel, Al and stainless steel base metal X-ray diffraction (XRD).
[30]
7 and 8 are photographs observed before and after the heat treatment of stainless steel, the addition of a non-stainless steel, the addition of Sn of the present invention.
Best Mode for Carrying Out the Invention
[31]
An exemplary heat and condensate corrosion is improved ferritic stainless steel for automobile exhaust system according to an embodiment of the present invention includes, in weight%, C: 0.01% or less, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5%, Sn: stainless steel base material containing 0.03% to 0.5%, and balance of Fe and other unavoidable impurities and it includes an aluminum-plated layer formed on the stainless steel base metal, (Al at the interface between the stainless steel base metal and the aluminum plating layer 19 FeMnSi 2 ) 5,31 comprises a compound coating containing (aluminum Iron Manganese Silicide).
Mode for the Invention
[32]
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.
[33]
According to one embodiment of the present invention, a ferritic stainless steel for automobile exhaust system is, percent, C parts by weight: not more than 0.01%, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01 It comprises 0.03% to 0.5%, and balance of Fe and other unavoidable impurities:% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5% Sn.
[34]
And present in an interstitial element of C and N to form a cargo Ti (C, N) carbonitride is, the higher the the content of Ti (C, N) no cargo forming carbonitride, C and N present in the employment of the material, when lowering the elongation and low temperature impact properties and, for a long time in the post-weld below 600 ℃ Cr 23 C 6 is a carbide is produced, since the mouth system unit expression occurs in amounts to at most 0.01%, N 0.01% for C it is preferable to control.
[35]
As well as, C + N When the content is higher, if the increased addition of the Ti content of the rigid many surface defects such as seukaep (scab) occurs as inclusions increases, and further employment with the problem of clogging the nozzles when playing occurs C , since the elongation and impact properties by increasing N deterioration C + N content it is preferably controlled to 0.02% or less.
[36]
Si is the higher the stability of the ferrite element is increased when the content of ferrite-phase-forming elements are added as a deoxidizing element. Si is to be improved and oxidation characteristics of the official potential increase of the content is increased. In the present invention, it is preferred that the addition of at least 0.5% and for the purpose of improving the oxidation characteristics of formula potential. When the amount of Si is increased to more than 1.0%, it is preferred that the stiffness that controls that does not exceed a maximum of 1.0% or more increases, and a problem occurs such as the surface defect of the Si inclusions.
[37]
Mn lowers the pitting resistance by forming precipitates such as MnS the higher the content. However, excessive reduction of Mn is preferably controlled to 0.5% or less because it leads to such an increase in refining costs.
[38]
P, S is preferably included to form such a grain boundary segregation and MnS seokmul water lowers the hot workability small as possible. However, excessive reduction is preferably controlled to cause it to less than the case of P is 0.035% or less, S is 0.01%, and the like increase in the purification cost.
[39]
Cr is an essential element for ensuring the corrosion resistance of stainless steel. If the content of Cr is low in corrosion resistance is reduced in an atmosphere of condensate, the content is too high and the ground improves the corrosion resistance, but the high strength and elongation, the impact resistance is lowered is caused a rise in manufacturing costs. Therefore, it is desirable to control the amount of from 10 to 18% Cr.
[40]
Ti is an element effective for preventing intergranular corrosion caused by immobilizing the C, N. However, since the problem of mouth expression system unit generating the corrosion resistance or the like generated by degradation Ti / (C + N) ratio decreases, welds, Ti is preferably controlled to at least 0.15%. However, the addition amount of Ti becomes too high, the rigidity of inclusions is increased to receive a significant amount of surface defects, such as seukaep (scab), and also because the problem of clogging the nozzles when playing phenomenon occurs that the content to 0.5% or less it is preferable to control.
[41]
Sn is an essential element for ensuring corrosion resistance in the heat resistance and the condensed water in the atmosphere to which the present invention targets.
[42]
In order the present invention, in order to ensure the heat resistance and corrosive condensate is preferable to control the Sn in at least 0.03%. However, a problem with the manufacturing process due to the excessive addition of Sn can result it is desirable to control its upper limit to 0.5%. More preferably, the content of Sn can be controlled to 0.05 to 0.5%.
[43]
One example ferritic stainless steel according to the embodiment of the present invention, Al may be coated ferritic stainless Gangil, which comprises an aluminum coating layer formed on the stainless steel base metal and the stainless steel base material.
[44]
The ferritic stainless steel according to one embodiment of the present invention (Al plating as compound at the interface between the stainless steel base metal and the aluminum plating layer 19 FeMnSi 2 ) 5,31 comprises (Aluminum Iron Manganese Silicide).
[45]
Alternatively, the ferritic stainless steel according to one embodiment of the present invention, Al as a coating compound at the interface between the stainless steel base metal and the aluminum plating layer 17 (Fe 32 Mn 0.8 ) Si 2 not include (Aluminum Iron Manganese Silicon) no. This causes a difference in the composition of the coating compound formed at the interface between the Sn-plated stainless steel as a non-added Al compound formed on the plated steel, that is, the stainless steel base metal and the aluminum plating layer according to the Sn is added or not.
[46]
For example, the coating compound is Al 9 FeSi 2 (Aluminum Iron Silicon), Al 3 FeSi 2 (Aluminum Iron Silico), may further include any one or more selected from the group consisting of Al (Aluminum).
[47]
The ferritic stainless steel according to one embodiment of the present invention are Sn is concentrated at least 4.5 times compared to the stainless steel base metal in the surface portion of the stainless steel base metal adjacent to the aluminum plate layer. Sn has a relatively strong affinity with oxygen is oxidized scale can be concentrated on a surface portion of stainless steel, which is formed in comparison to the other element.
[48]
For example, there may be a Sn on the surface of said stainless steel base material is 4.5 to 6.1 times thicker than the stainless steel base material.
[49]
The stainless steel not only has an area Sn is concentrated on the surface part, (as Al compound coated on the interface between the stainless steel base metal and the aluminum plating layer 19 FeMnSi 2 ) 5,31 by including (Aluminum Iron Manganese Silicide) , does not contain Sn, compared to the ferritic stainless steels are not the concentrated Sn on the surface portion, it is possible to obtain the desired improved heat resistance and corrosion resistance to condensed water.
[50]
Figure 1 is a graph showing the maximum depth of the formula in a stainless steel non-added stainless steel automotive exhaust system according to the present invention the addition of Sn condensate solution graph.
[51]
The embodiment of Figure 1 is a ferritic stainless steel by the addition of Sn in accordance with an embodiment of the present invention and Comparative Examples are the maximum condensate corrosion properties to target the conventional Al-plated steel 409L after evaluation (JASO-M611-92 B) It shows the official depth.
[52]
For example, ferritic stainless steel according to one embodiment of the present invention has the formula The maximum depth may be below 0.4mm, when condensate corrosion property evaluation (JASO-M611-92 B). In contrast, conventional Al-plated steel 409L represents the maximum depth of about 0.6mm greater than the official.
[53]
For example, ferritic stainless steel has a surface color difference (△ E) before and after the heat treatment of stainless steel in accordance with one embodiment of the present invention may be 10 or less.
[54]
Production method of ferritic stainless steel in accordance with one embodiment of the present invention can be prepared for a ferritic stainless steel slab containing the above composition after the step of hot rolling, hot-rolled and annealed, annealing hot-rolled steel pickling, cold rolling and finishing, this production process may be a conventional STS 409L manufacturing process. Then, after an aluminum plating process, the cold-rolled steel sheet can be manufactured in the Al-coated ferritic stainless steel.
[55]
For example, the manufacturing method of ferritic stainless steel in accordance with one embodiment of the present invention further comprises the step of heat treating the aluminum coated with the ferritic stainless steel at a temperature of 300 to 500 ℃ within 48 hours, and the in this case stainless steel surface color difference before and after the heat treatment Steels (△ E) may be 10 or less.
[56]
[57]
It will now be described in detail to a ferritic stainless steel for automobile exhaust system according to an embodiment of the present invention through the embodiments.
[58]
To honor
[59]
Invention steel 1
[60]
To thereby prepare a ferritic stainless steel slab composition as the composition of the invention steel 1 in Table 1. By hot-rolling the slab at a temperature of 1,150 ℃ to prepare a hot-rolled steel sheet of 3.0mmt. After annealing the hot-rolled steel sheet, acid pickling after performing the final annealing, pickling process to prepare a cold-rolled steel sheet of 1.2mmt by cold rolling, subjected to a final Al-coated Al-coated ferritic stainless steel product was prepared.
[61]
Invention steel 2
[62]
To was prepared in the same manner as the inventive steels 1, except that the composition of the invention steel 2 in Table 1.
[63]
Invention steel 3
[64]
To was prepared in the same manner as the inventive steels 1, except that the composition of Table 1, the inventive steels 3.
[65]
Comparative Steel 1
[66]
To was prepared in the same manner as the inventive steels 1, except that the composition of the comparative steel 1 in Table 1.
[67]
Comparative Steel 2
[68]
To was prepared in the same manner as the inventive steels 1, except that the composition of Comparative Steel 2 of Table 1.
[69]
TABLE 1
(wt%) C And Mn P S Cr Ti Sn N Ti / (C + N)
Invention steel 1 0.005 0.597 0.30 0.021 <0.003 11.14 0.22 0.048 0.0074 17.4
Invention steel 2 0.005 0.613 0.31 0.023 <0.003 11.21 0.21 0.11 0.0089 15.1
Invention steel 3 0.006 0.592 0.30 0.019 <0.003 11.24 0.24 0.2 0.0072 18.2
Comparative Steel 1 0.005 0.62 0.30 0.023 <0.003 11.24 0.22 0 0.0074 17.7
Comparative Steel 2 0.006 0.594 0.30 0.020 <0.003 11.29 0.23 0.02 0.0072 18.8

[70]
Table 2 shows the results of measuring the major components in the concentrated layer on the surface of the stainless steel base metal adjacent to the stainless steel base metal and the aluminum coating layer of the inventive steels 3.
[71]
TABLE 2
Concentrated layer 1 (wt%) Concentrated layer 2 (wt%) Concentrated layer 3 (wt%) Base material (wt%)
Fe 79.11074 83.80825 82.11589 88.5022
Cr 11.32846 9.647609 10.79504 10.30857
Al 6.784723 4.033176 4.799919 0.157073
And 1.798595 1.204887 1.276994 0.781254
Sn 0.977485 1.306278 1.012158 0.214902
Concentrated layer Sn / base material Sn 4.5 6.1 4.7 -

[72]
2 is a view illustrating results of analysis of the interface between the Al layer and the stainless steel the stainless steel base material was added to Sn of the invention in a transmission electron microscope (TEM) EDS (Energy-Dispersive Spectroscopy).
[73]
Referring to Figure 2 and Table 2, the ferritic stainless steel according to one embodiment of the present invention is that the Sn in the surface portion of the stainless steel base metal adjacent to the aluminum coating layer is thicker 4.5 to 6.1 times compared to the stainless steel base material It can be found.
[74]
3 is a view illustrating results of analysis of transmission electron microscopy (TEM) EDS (Energy-Dispersive Spectroscopy) with a line (line) from stainless steel, Al-plated layer by the addition of Sn of the present invention to the base material. 4 is a graph showing the interface between the analysis of X-ray diffraction (XRD) with the addition of Sn of stainless steel, Al-plated layer and the stainless steel base material of the present invention.
[75]
Referring to Figure 3, it can be seen that toward the base material from the plating layer was measured by Cr and Sn, Sn is concentrated on the surface part of the stainless steel base metal adjacent to the aluminum plate layer.
[76]
4, a coating compound at the interface between the stainless steel base metal and the plating layer of aluminum (Al 19 FeMnSi 2 ) 5,31 (Aluminum Iron Manganese Silicide), Al 9 FeSi 2 (Aluminum Iron Silicon), Al 3 FeSi 2 (Aluminum Iron Silico), it can be seen that including the Al (Aluminum).
[77]
5 is a view showing a line (line) analysis result of a transmission electron microscope (TEM) EDS (Energy-Dispersive Spectroscopy) from stainless steel, Al plating a non-addition of Sn to the base material. Figure 6 is a graph illustrating results of analysis of the interface between the non-addition of the Sn-plated layer of stainless steel, Al and stainless steel base metal X-ray diffraction (XRD).
[78]
Referring to Figure 5, it can be seen the result of the base material toward the stainless steel the non-addition of Sn from the plating layer measured Cr, and Sn, Sn is not naturally concentrated in the surface portion of the stainless steel base material.
[79]
Referring to Figure 6, as a coating compound at the interface between the stainless steel base metal and the aluminum plating layer Al 17 (Fe 32 Mn 0.8 ) Si 2 (Aluminum Iron Manganese Silicon), Al 9 FeSi 2 (Aluminum Iron Silicon), Al 3 FeSi 2 (Aluminum Iron Silico), it can be seen that including the Al (Aluminum). That is, (Al formed on the Sn-added steel 19 FeMnSi 2 ) 5,31 can identify the plating of the compound (Aluminum Iron Manganese Silicide) not formed.
[80]
[81]
Table 3 to Table 5 shows the results of the stainless steel of the comparative steel 1, a non-added stainless steel, and Sn of the invention steel 3 was added to Sn measure the whiteness before and after the heat treatment.
[82]
[83]
Experimental Example 1
[84]
To the invention to measure the whiteness of the steel before and after after performing a heat treatment on the stainless steel and 350 ℃ the stainless steel of the comparative steels 1 each of 3 for 24 hours, the heat treatment shown in Table 3 below.
[85]
TABLE 3
Before heat treatment whiteness After the heat treatment whiteness Color difference (△ E)
Invention steel 3 77.84 78.04 7.11
Comparative Steel 1 78.27 71.52 10.83

[86]
[87]
Experimental Example 2
[88]
To the after performing a heat treatment for 24 hours in a stainless steel, and 400 ℃ stainless steel of the comparative steel 1, each of the inventive steels 3 measures the whiteness before and after heat treatment are shown in Table 4.
[89]
TABLE 4
Before heat treatment whiteness After the heat treatment whiteness Color difference (△ E)
Invention steel 3 77.93 80.04 5.70
Comparative Steel 1 77.27 68.97 13.59

[90]
[91]
Experimental Example 3
[92]
To the after performing a heat treatment for 24 hours in a stainless steel, and 450 ℃ stainless steel of the comparative steel 1, each of the inventive steels 3 measures the whiteness before and after heat treatment are shown in Table 5.
[93]
Table 5
Before heat treatment whiteness After the heat treatment whiteness Color difference (△ E)
Invention steel 3 78.95 79.50 5.38
Comparative Steel 1 77.59 65.80 15.35

[94]
7 and 8 are photographs observed before and after the heat treatment of stainless steel, the addition of a non-stainless steel, the addition of Sn of the present invention.
[95]
7 is a picture taken of the surface of stainless steel according to the Experimental Example 2, Figure 8 is a photograph taken of the surface of stainless steel according to the Experimental Example 3.
[96]
When the Experimental Example and with reference to Figures 7 and 8, when Sn US added river becomes the color of the steel material surface dark after heat treatment, but the whiteness is to find out degraded, even if carried out, if Sn is added Steel Heat Treatment of whiteness decreases almost no , for example, it can be seen that the difference in brightness represents the most 10. Accordingly, when adding Sn lecture can confirm the heat resistance is excellent compared to non-Sn-added steel.
[97]
[98]
Evaluation of corrosion resistance was evaluated according to the corrosive condensate JASO-M611-92 B of Japanese standards. I.e., Cl - concentration: 100ppm, NO 3 - concentration: 20pmm, SO 3 2- concentration: 600pmm, SO 4 2- 600pmm, CH: Concentration 3 COO - to 80 ℃ in an aqueous solution of 8.0 ± 0.2: Concentration: 800pmm, pH the clock maintained by repeated 5 times and then 250 ℃ 1 cycle (cycle) for 24 hours in a holding measure the maximum depth of formula after a total of 4 cycles repeated.
[99]
After the stainless steel according to the invention steel 3 and comparative steel 1 reviews of the corrosive condensate in accordance with the following method by measuring the maximum depth of formula are shown in Table 6.
[100]
TABLE 6
The official maximum depth (mm)
Invention steel 3 0.35
Comparative Steel 1 0.66

[101]
Figure 1 is a graph showing the maximum depth of the formula in a stainless steel non-added stainless steel automotive exhaust system according to the present invention the addition of Sn condensate solution graph.
[102]
The embodiment of Figure 1 is a ferritic stainless steel by the addition of Sn of the invention steel 3, a comparison example is a conventional Al-plated steel 409L in Comparative Steel 1. Referring to Figure 1 and Table 6, the inventive steels 3 it can be seen that the condensate corrosion property evaluation (JASO-M611-92 B) when the maximum depth of the formula represents the 0.35mm, the comparative steel 1 represents a 0.66mm .
[103]
As a result, it can be seen that when adding the Al having a Sn plating of ferritic stainless steels, excellent corrosion resistance and heat resistance of condensate in accordance with embodiments of the present invention.
[104]
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
[105]
The ferritic stainless steel in accordance with embodiments of the present invention can be to expensive even heat and corrosive condensate unless the addition of elements such as Cr, Mo excellent application for automotive exhaust system.
[106]

Claims
[Claim 1]
By weight%, C: 0.01% or less, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5%, Sn: in ferritic stainless steel containing 0.03% to 0.5%, and balance of Fe and other unavoidable impurities the stainless steel base metal and an aluminum coating layer formed on the stainless steel base material containing the stainless steel base metal and the interface to the (Al between the aluminum plating layer 19 FeMnSi 2 ) 5,31 ferritic stainless steel for (aluminum Iron Manganese Silicide) a car exhaust system including a heat and corrosive condensate containing coating compound for the improvement.
[Claim 2]
According to claim 1, wherein the coating compound is Al 9 FeSi 2 (Aluminum Iron Silicon), Al 3 FeSi 2 heat resistance comprises at least one selected from the group consisting of (Aluminum Iron Silico), Al ( Aluminum) more and within condensate ferritic stainless steel for corrosion resistance improved automotive exhaust systems.
[Claim 3]
According to claim 1, wherein said aluminum coating layer wherein the stainless steel base material surface portion to the stainless steel base metal is Sn than 4.5 times more than the ferritic stainless steel for heat resistance and the corrosion resistance is improved in the condensate in automobile exhaust system close to the concentration of the.
[Claim 4]
According to claim 3, wherein the stainless steel base material surface portion to the stainless steel base metal is Sn than 4.5 to 6.1 times the heat resistance and the ferritic stainless steel for automobile exhaust system within the condensate with caustic improvement in thickening of the.
[Claim 5]
Claim 1 wherein, Sn to: a ferritic stainless steel for heat resistance and the corrosion resistance is improved in the condensate automotive exhaust system comprising a 0.05 to 0.5%.
[Claim 6]
According to claim 1, condensate corrosion property evaluation ferritic stainless steel for (JASO-M611-92 B) when, with a maximum depth of formula improved the heat resistance and corrosion condensate than 0.4mm automotive exhaust system.
[Claim 7]
According to claim 1, wherein the heat treatment of stainless steel surface before and after the color difference (△ E) is 10 or less of ferritic stainless steel for heat resistance and the corrosion resistance is improved in the condensate in automobile exhaust systems.
[Claim 8]
By weight%, C: 0.01% or less, Si: 0.5 to 1.0%, Mn: 0.5% or less, P: 0035% or less, S: 0.01% or less, Cr: 11 to 18%, N: 0.013% or less, Ti: 0.15 to 0.5%, Sn: the step of hot rolling a ferritic stainless steel slab containing 0.03% to 0.5%, and balance of Fe and other unavoidable impurities; Cold rolling the hot-rolling a hot-rolled steel sheet; Production method of ferritic stainless steel for heat resistance and the corrosion resistance is improved condensate automotive exhaust system comprising; and a step of aluminum plating the cold-rolled cold-rolled steel sheet.
[Claim 9]
The method of claim 8, wherein the ferritic stainless steel is 409L STS conventional manufacturing process heat resistance and the method for manufacturing a ferritic stainless steel for automobile exhaust system is improved in the condensate with caustic produced.
[Claim 10]
The method of claim 8 wherein the aluminum coated with the ferrite further comprising the step of heat treatment at a temperature of 300 to 500 ℃ within 48 hours of stainless steel, the heat treatment before and after the surface of the color difference (△ E) is 10 or less heat and condensate corrosion the manufacturing method of ferritic stainless steels for automotive exhaust system is improved.