1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Changes 1999 11 22 N - Status Replaced by WSS - M1A341 - A1 1996 06 13 Activated J. Nelson WP 3948 - a Page 1 of 5 STEEL, SHEET, DENT RESISTANT WSS - M1A339 - A1 NOT TO BE USED FOR NEW DESIGN 1. SCOPE The material def
2、ined by this specification is steel sheet which has enhanced strength compared to CRLC steel. Specification WSS - M1P94 - A shall be specified where preco ating by the steel supplier is required. 2. APPLICATION This specification was released originally for material used in body components to improv
3、e dent resistance. Due to higher tensile and yield strength properties attainable with this product, downgaging with subsequent cost and weight savings are possible. CAUTION: The maximum yield strength is not specified, therefore for test or evaluation purposes, it is essential that prototype parts
4、are produced using material with maximum yield strengths with in 10 % of the grade level specified. 3. REQUIREMENTS 3.1 QUALITY SYSTEM REQUIREMENTS Material suppliers and part producers must conform to Quality System Requirements, QS - 9000. Material specification requirements are to be used for ini
5、tial qualification of materials. A Control Plan for ongoing production verification is required. This plan must be reviewed and approved by the relevant Ford Materials activity and/or Ford Supplier Technical Assistance (STA) prior to production parts submission. App ropriate statistical tools must b
6、e used to analyze process/product data and assure consistent processing of the materials. Part producers using this material in their products, must use Ford approved materials and must conform to a process control plan which has been approved by STA and/or the relevant Materials Activity. 3.2 CHEMI
7、CAL COMPOSITION Base material shall have a low carbon steel composition. ENGINEERING MATERIAL SPECIFICATION WSS - M1A339 - A1 WP 3948 - b Page 2 of 5 3.3 MECHANICAL PROPERTIES (ASTM A 370, ISO 6892) Grade 210 As Received by Ford: Yield Strength, typical, MPa 240 Yield Strength, min, MPa 210 Tensile
8、Strength, typical, MPa 375 * Elongation, typical, % 38 Note: Tension specimens shall be taken longitudinally from the coated finished sheet and shall conform to the standard sheet type specimen shown in ASTM A 370, ISO 6892. * Gage lengths other than 50 mm may be used for control purposes with appro
9、priate correction in % elongation. In all cases, 50 mm will be considered the umpire standard gage length. 3.4 GRAIN SIZE No. 8 and finer (ASTM E 112) 3.5 BEND TEST (ASTM A 607) Test samples shall pass a 180 degree transverse bend test at room temperature with the inside bend diameter not exceeding
10、the specimen thickness. 3.6 SURFACE FINISH The material shall have a workmanlike appearance and shall not have defects of a nature or degree for the grade and quality ordered that will be detrimental to the fabrication of the finished part. The need for a final temper mill reduction to control surfa
11、ce appearanc e or formability is to be negotiated between the manufacturing activity and the steel supplier. 3.7 PAINTABILITY Material supplied to this specification must have prior approval for paintability by the responsible Materials Engineering activity. This approval shall be based on samples p
12、repared to the local process and resistance requirements appropriate to the country of Ford vehicle manufacture, or to the relevant Engineering Performance Specification, see section 5.2. 3.8 WELDABILITY (Spot Weld) Coated steel shall conform to the requirements of Ford Welding Acceptance Test Metho
13、d FLTM BA 13 - 4. ENGINEERING MATERIAL SPECIFICATION WSS - M1A339 - A1 WP 3948 - b Page 3 of 5 3.9 FORMABILITY The quality level of steel supplied to fabricate a specific component is to be negotiated between the Manufacturing activity and the steel supplier. Acceptance of subsequent orders by the s
14、teel supplier for a given component at the agreed upon quality level implies that all steel supplied will form that part satisfactorily as defined by the Manufacturing activity. 3.10 SUPPLIERS RESP ONSIBILITY All materials supplied to this specification must be equivalent in all characteristics to t
15、he material upon which approval was originally granted. Prior to making any change in the properties, composition, construction, color, processing or labeling of the material originally approved under this specification, whether or not such changes affect the materials ability to meet the specificat
16、ion requirements, the Supplier shall notify Purchasing, Toxicology and the affected Materials Engineeri ng activity of the proposed changes and obtain the written approval of the Materials Engineering activity. Test data, test samples and a new code identification are to be submitted with the reques
17、t. Substance restrictions imposed by law, regulations or Ford, apply to the materials addressed by this document. The restrictions are defined in Engineering Materials Specification WSS - M99P9999 - A1. 4. APPROVAL OF MATERIALS Materials defined by this specification must have prior approval by the
18、responsible M aterials Engineering activity. Suppliers desiring approval of their materials shall first obtain an expression of interest from the affected Purchasing, Design and Materials Engineering activity. Upon request, the Supplier shall submit to the affected Materials Engineering activity a c
19、ompleted copy of their laboratory test reports, signed by a qualified and authorized representative of the test facility, demonstrating full compliance with all the requirements of this specification (test results, not nomina l values), the material designation and code number, and test specimens fo
20、r Ford evaluation. Fords engineering approval of a material will be based on its performance to this specification and on an assessment of suitability for intended processes and/or applications. Upon approval, the material will be added to the Engineering Material Approved Source List. ENGINEERING M
21、ATERIAL SPECIFICATION WSS - M1A339 - A1 WP 3948 - b Page 4 of 5 5. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of this specification . 5.1 INITIAL SUPPLIER APPROVAL For initial approval, the supplier must furnish the follow
22、ing information for each grade. . A plan detailing how each requirement of para 3 will be controlled on a continuing production basis. . Test results from a typical production sample for the requirements outlined in para 3. . Paintability test results from typical production samples as outlined in p
23、ara 5.2. . Mechanical property histograms including mean and standard deviation values. Data shall consi st of a minimum of 40 measurements for each property, in para 3.3, taken from 20 coils while the process is operating in statistical control. Upon approval, the material will be added to the Engi
24、neering Material Approved Source List. 5.2 PAINTABILITY TEST METHODS Material supplied to European Automotive Operations (EAO) shall meet the requirements of WSK - M2P136 - A. Material supplied to North American Automotive Operations (NAAO) shall meet the following requirements: . Material intended
25、for Class 1 surface applications shall meet the requirements of ESB - M2P130. . Material intended for Class 2 and 3 surface applications shall meet the requirements for ESB - M2P129. A Class 1 surface shall be specified for parts of the body or front end sheet metal that are exposed after paint or t
26、rim. A Class 2 surface shall be specified for parts of the body not covered by trim materials but exposed to view when the car doors or enclosure lids are in an open position. Class 3 metal surface specificat ions are parts that are wholly or partially concealed during normal use of the vehicle. Par
27、ts such as fender aprons, floor pans and unexposed underbody structural members, typify parts that would be specified as Class 3. ENGINEERING MATERIAL SPECIFICATION WSS - M1A339 - A1 WP 3948 - b Page 5 of 5 5.3 YIELD STRENGTH VS. PRESTRAIN For purposes of design, it may be desirable to predict yield strength at various locations on the finished part. The following indicates increase in yield strength due to strain hardening only (no thermal treatment). Yield Strength Increase % Res train MPA KSI 0 0 0 1 27 3.9 2 47 6.8 3 66 9.6 4 76 11.0 6 97 14.1 8 101 16.0
