1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW15614 Cold Rolled Stainless Steel Strip and Sheet for Trim Applications Copyright 2013 General Motors Company All Rights Reserved August 2013 Page 1 of 9 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note
2、: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Material Description. The material described in this specification includes both ferritic and austenitic grades of stainless steel for use in automotive trim. Stainless steels are se
3、lected primarily for their resistance to cosmetic corrosion. This corrosion may come in multiple forms: General (surface becomes brown-appearing overall or in stained areas, and can be cleaned with polish), or Pitting (highly localized small spots, often surrounded by rust “bulls-eye”, and cannot be
4、 permanently cleaned by polish). Also, intergranular corrosion may affect structural integrity with only minor visible change. Resistance to general corrosion is proportional to the percent chromium content. Resistance to pitting corrosion is proportional not only to chromium but also (more strongly
5、) to percent molybdenum content. Intergranular corrosion only occurs in weld heat affected zones and is reduced when carbon content is reduced; thus, only “L” (low carbon) grade material may be used for welded applications. Stainless types that are titaniumstabilized for intergranular corrosion resi
6、stance will have visible dark spots/streaks and are not recommended for the cosmetic applications covered by this specification. 1.1.1 Material Identification. Refer to Table 1. 1.2 Symbols. Not applicable. 1.3 Typical Applications. Interior or exterior bright metal trim. 2 References Note: Only the
7、 latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. AISI 3 ASTM E112 SAE 30301 SAE 51434 ASTM A370 EN 10088-2 SAE 30304 SAE 51436 ASTM A651 JIS G4305 SAE 51409 SAE J405 ASTM E18 SAE 30201 SAE 51430 SAE J409 2.2 GM Standards/Specifications. GMW
8、3059 GMW14458 GMW15284 GMW16854 GMW3161 GMW15283 GMW15613 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents (available at ). 3 Requirements 3.1 Alloy Selection. Other equivalent regional stainless grades may be used as purchasing availability necessitates, as approved b
9、y GM Materials Engineering. 3.1.1 Pitting Resistance. When selecting the type of stainless steel for an application (or, if investigating other grades), consider the calculated Pitting Resistance Equivalent (PRE), a single reference number indicative of overall corrosion performance. PRE = %Cr + 3.3
10、(%Mo) The minimum specified limits of those alloys referenced here show rankings in Table 2. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS
11、 GMW15614 Copyright 2013 General Motors Company All Rights Reserved August 2013 Page 2 of 9 3.1.2 Appearance. The color of ferritic grades is slightly blue, and is slightly yellow for austenitic grades. Alloys should not be intermixed in appearance zones. Also, no stainless alloys will exactly match
12、 chrome flashed or nickel-chrome plated parts. 3.1.3 Exhaust Component Usage. While not notably helpful for salt corrosion resistance, the nickel present in austenitic alloys aids resistance when corrosive exhaust gas condensates are present. Types 304 or 316 (“L” if welded) are to be used, and only
13、 up to a service temperature of 200 C. Above this temperature, objectionable yellowing will occur and chrome flashing (to 300 C) or nickel chrome plating (to 400 C) is required. Reference GMW15613. Table 1: Material Identification Table Note 1 GMW15614 Type XXX Designation Common Name SAE Designatio
14、n Other Designations (UNS, ISO, EN, JIS, etc.) Comments (Usage, Requirement, and Others) Ferritic Stainless Steel Grades GMW15614 Type 434 434 SAE 51434 UNS S43400, ASTM A651, EN 10088-2-1.4113, (X6CrMo17-1), JIS G4305 SUS434 Use if moderate resistance to pitting and rusting is required. Use when ro
15、ping control is not required. Use when corrosion requirements are not severe. GMW15614 Type 436 436 SAE 51436 UNS S43600, JIS G4305 SUS436L Similar corrosion resistance as Type 434 grade. Use when roping control is required. GMW15614 Type 436M (GMW15614 Type 436M1) (GMW15614 Type 436M2) 436M - - Imp
16、roved corrosion resistance to Type 434 and Type 436. Similar roping performance as Type 436. Type 436 M1 and Type 436M2 Note 2 are chemistry modified versions of Type 436 (SAE 51436). GMW15614 Type 430 430 SAE 51430 UNS 43000, EN 10088-2-1.4016 (X6Cr17), JIS G4305 SUS 430 Similar Chrome content to T
17、ype 434/436 grades, but no Molybdenum (Mo). Corrosion resistance is poor comparative to Type 434/436 grades. May only be used as a substrate for co-extruded coating, or restricted local/regional markets where corrosive environment is mild. GMW15614 Type 409 409 SAE 51409 UNS S40900, DIN EN 10088-2 X
18、2CrTi12 (1.4512), JIS G4305 SUS409 Minimum Chromium (Cr) content of 10.5%. Due to low Cr content, should not be considered for cosmetic applications. For exhaust system applications, refer to GMW3161 specification. Copyright General Motors Company Provided by IHS under license with General Motors Co
19、mpanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15614 Copyright 2013 General Motors Company All Rights Reserved August 2013 Page 3 of 9 GMW15614 Type XXX Designation Common Name SAE Designation Other Designations (UNS, ISO
20、, EN, JIS, etc.) Comments (Usage, Requirement, and Others) GMW15614 Type 444 444 - UNS S44400, EN 10088-2-X2CrMoTi18-2 JIS G4305 SUS444 Excellent corrosion resistance (especially pitting corrosion resistance); approximately equivalent to Type 316 but without added cost of Nickel (Ni). Not suited for
21、 cosmetic applications due to its Titanium (Ti) content. GMW15614 Type 201 201 SAE 30201 UNS S20100 EN 10088-2-X12CrMnNiN 17-7-5 (1.4372) Strong and ductile stainless grade. Similar corrosion resistance to Types 434 and 436. Used in automotive trim fabrication where increased ductility for deep draw
22、ing is required. Use when moderate atmospheric corrosion resistance is required. GMW15614 Type 301 301 SAE 30301 UNS S30100 EN 10088-2-1.4310 (X10CrNi18-8), JIS G4305 SUS 301 Has greater formability than the ferritic grades and Type 201. It is used for trim parts requiring deep drawing or stretching
23、 operations. Use when increased atmospheric corrosion resistance is required. GMW15614 Type 304L 304L SAE 30304L UNS S30403 EN 10088-2-1.4306 (X2CrNi19-11) JIS G4305 SUS304L Used when corrosion environments are extreme, such as exhaust tips and assist steps. GMW15614 Type 304 304 SAE 30304 UNS S3040
24、0 EN 10088-2-1.4301 (X2CrNi18-10) JIS G4305 SUS304 This is a “non-L” type of 304 grade; it is to be used if a component is not to be welded. Same usage as Type 304L. GMW15614 Type 316L 316L - UNS S31603 EN 10088-2-1.4435 (X5CrNiMo17-12-2) JIS G4305 SUS316L Used when corrosion environments are extrem
25、e, such as exhaust tips and assist steps. Relative to 304, this grade has additional resistance to crevice and pitting corrosion and less resistance to general corrosion. GMW15614 Type 316 316 - UNS S31600 EN10088-2-1.4401 (X2CrNiMo17-12-2) JIS G4305 SUS 316 This is a “non-L” type of 316 grade; it i
26、s to be used if a component is not to be welded. Same usage as Type 316L. GMW15614 Type 317 317 - UNS S31700 EN 10088-2 (X5CrNiMo17-13-3) JIS G4305 SUS317 May be used for exterior trim applications, where corrosion performance is critical but slightly yellow appearance is acceptable. Excellent corro
27、sion resistance. Excellent intergranular corrosion resistance. Note 1: If part is made from buffed austenitic grades, chrome flashing is required for color matching due to heat tinting during the buffing operation. Note 2: Deformation of 1% to 2% during forming will likely need to be polished to res
28、tore finish (section 3.3.1). Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15614 Copyright 2013 General Motors Company All Rights Reser
29、ved August 2013 Page 4 of 9 3.1.4 Other Considerations. If dissimilar alloys are joined, thermal expansion differences must be considered to avoid component stress and/or warping. Stressed components may require appropriate testing for stress corrosion cracking susceptibility. Table 2: Alloy Ranking
30、 and Minimum Specification Limits Alloy Type PRE % Cr % Mo % Ni 201, 301, 430 16 16 - 201: 3.5 301: 6 304 18 18 - 8 434 Note 1, 436 18.5 16 0.75 - 436M2 21 17 1.2 - 316 22.6 16 2 10 436M1 23 20 0.9 - 444 24.1 17.5 2 - 317 27.9 18 3 11 Note 1: It should be noted that 434 type material in North Americ
31、a has pitted and performed poorly on body sides and side window areas. 3.2. Chemical Requirements. 3.2.1. Chemical Compositions. The chemical composition of the stainless steel shall conform to the standard chemistry of the corresponding SAE grades per SAE J405 and SAE J409, EN 10088-2, or to other
32、national or international equivalent. The chemical composition of Type 436M shall conform to either of the chemistries shown in Appendix A, Table A1. 3.3 Mechanical Requirements. The mechanical properties of the material furnished shall be agreed upon between GM engineering and supplier. Whatever pr
33、actices employed to meet the negotiated requirements shall allow no significant loss of finish quality. Reference properties for some alloy types are shown in Appendix A. 3.3.1 Ferritic grades deformed more than 1% to 2% frequently will require polishing to restore bright appearance. 3.4 Physical Re
34、quirements. 3.4.1 Finish. 3.4.1.1 The supplied finish shall be designated by a suffix letter added to the basic type number (such as GMW15614, Type 301C for bright annealed) for the particular finish desired as in Table 2. Surface appearance (brightness, gloss, color, texture) shall conform to the c
35、orresponding GM finish standards supplied by Finish and Textile Engineering vehicle group, or equivalent, in each region. Polishing/buffing shall have no negative effect on corrosion protection. 3.4.1.2 The following criteria for finish evaluation apply to Type 434, Type 436 and Type 436M. 3.4.1.2.1
36、 Bright annealed 436M2 Appearance Standard Panel gives the minimum acceptance appearance for all incoming ferritic stainless steel strip. 3.4.1.2.2 Two pre-buffed panels may supplement the bright annealed standard by indicating the maximum acceptable severity of buff lines for the specific applicati
37、on. 3.4.1.2.3 The ribbing level on incoming material shall be three or better for 434 and two or better for 436 and 436M based on General Motors visual standards provided by the Finish and Textile Engineering vehicle groups or by the comparable standards in the respective regions. 3.4.2 Corrosion Re
38、sistance. Materials supplied to this specification must meet the following corrosion resistance requirements: 3.4.2.1 During mill processing, the stainless steel shall not be sensitized. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reprod
39、uction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15614 Copyright 2013 General Motors Company All Rights Reserved August 2013 Page 5 of 9 3.4.2.2 Spot Test (GMW15284). No etching, dulling, color change or other appearance changes visible to the unaided
40、 eye when viewed perpendicular to the surface. Pitting requirements are as follows: A maximum of 2 pits in the center of the test area are allowed and pits which touch the wax ring are not counted. Ten times (10x) magnification is recommended for pit analysis. 3.4.2.3 Copper Accelerated Acetic Acid
41、Salt Spray (CASS) Test (GMW14458). No corrosion sites, identified as red rust rundown or pitting, are permitted on the surface of the metal after 16 h test. Discoloration can be permitted up to 2% maximum (discounting corrosion from sheared edges). 3.4.2.4 Cycle Immersion (GMW15283). No corrosion on
42、 surface after 100 cycles (3 h). This test is for material qualification and not a quality control type test. Individual supplier may choose to use this test continuously to monitor their product. Table 3: Material Surface Finish and Codes Suffix Code Letter Sheet and Strip Finish Designation Descri
43、ption Typical Usage C Bright Annealed This is a bright, cold rolled, highly reflective finish attained by final annealing under controlled atmosphere which prevents scaling and oxidation. Minimized amounts of buffing required after fabrication. This material is to be skin passed after bright anneali
44、ng. Note 1, Note 2 Used for miscellaneous automotive moldings when severe deep drawing or forming is not performed. May be used alone or when component is to be nickel-chrome plated. Note 3 D Bright Annealed and Buffed or Electropolished The same basic material described above followed by additional
45、 surface finishing. Bright annealed material must be buffed thoroughly or electropolished before it will accept a chrome flash without frosting. Note 1, Note 2 Generally for austenitic grades, recommended for parts to be chrome flashed Note 3 for appearance match instead of plain bright annealed. F
46、Bright Annealed and Buffed The same basic material described above followed by component buffing to meet GM Engineering part appearance standards. Note 2 Generally for ferritic grades that require post-forming polishing to restore appearance. Note 1: The surface finish of bright annealed and bright
47、annealed and buffed finishes of Types 201 and 301 shall be equal to or better than the GM visual standard (dated February 1990 or latest) provided by the Finish and Textile Engineering vehicle groups or by the comparable standards in the respective regions. Note 2: The surface finish of cold rolled
48、stainless steel of Type 434, Type 436 and Type 436M shall be equal to or better than the GM visual standards (dated February 1990 or latest) available from the Finish and Textile Engineering vehicle groups or by the comparable standards in the respective regions. Note 3: For plating requirements, re
49、ference GMW15613. 3.4.3 Roping Susceptibility. Roping is the tendency of a material to form visible, parallel longitudinal lines on the surface as the result of tensile deformation. In previous versions of this specification, samples were required to be stretched 15% and compared to physical samples to determine acceptability. Those samples are no longer available for global us
