1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16823 Surface Condition Requirements for Steel and Aluminum Sheet Copyright 2012 General Motors Company All Rights Reserved November 2012 Originating Department: North American Engineering Standards Page 1 of 6 1 Scope This standard covers t
2、he surface condition requirements for uncoated and coated steel sheet, as well as aluminum, which will be cleaned, surface treated, primed and painted. These requirements apply to sheet metals stamped inside GM as well as by its parts and steel suppliers, processing centers and service centers. The
3、surface conditions covered by this specification include: Oxides, carbon and carbonaceous deposits, roughness, surface treatments such as passivation and conversion coatings and marking. The intent of this specification is to insure the surface condition of the metal surface is compatible with subse
4、quent paint processing to provide a high quality appearance and high durability that meet all of GMs global requirements. Due to the regional nature of manufacturing processes, suppliers must understand the different requirements in each region and must also meet the needs of the region using these
5、materials. Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Material Description. Not applicable. 1.2 Symbols. Not applicable. 1.3 Typical Applications.
6、 Materials covered by this specification include, but are not limited to, steel and aluminium stampings, roll formed parts, tubes, used in body structure, chassis, powertrain, interior and exterior applications where the surface condition is important prior to preparation for application of paints o
7、r passivations. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. EN 10049 SAE J911 2.2 GM Standards/Specifications. GMW3011 GMW16170 GMW3059 GMW16546 2.3 Additional References. TMC003 Material Safety Data Sheet gu
8、idance documents (available at ). 3 Requirements 3.1 Surface Contaminants. Surface contaminants, oxides and carbonaceous deposits that may affect painting or joining are prohibited. 3.1.1 Metallic Oxides. Metallic surfaces shall be free of any oxides or contaminants that may negatively affect materi
9、al processing, manufacturability or performance. Some examples of commonly found surface oxides and contaminants that are not considered acceptable are shown in Table 1. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or network
10、ing permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16823 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 2 of 6 Table 1: Surface Oxides and Contaminants for Steel and Aluminum Substrate Oxide Steel Red Rust Blue Oxidation (heat) Yellow Oxida
11、tion (heat) White Oxide (Zinc Oxide) Severe Water Stains Aluminum White Oxide (Aluminum Oxide) Severe Water Stains 3.1.2 Surface Carbon (Qualification Testing). Suppliers shall maintain processes such that the following requirements are met. For purposes of this specification, suppliers shall valida
12、te to this requirement for initial qualification. In cases where there is a question about carbon based surface contamination, this requirement shall be used as the basis for material evaluation. The total surface carbon and carbonaceous deposits on coated and uncoated exposed (E) sheet steels shall
13、 not exceed 4 mg/m2 (milligrams per square meter) for continuously annealed steels and 10 mg/m2 for batch annealed steels. Testing shall be performed on samples that have been solvent cleaned to remove all surface oils. The measurement method used shall show acceptable repeatability and reproducibil
14、ity (R&R) as agreed between supplier and purchaser. Surface carbon can also affect the performance of paint films on uncoated structural steels in non-visible applications and, as a result, could affect corrosion performance and life expectancy of a part. The performance of structural steels will ul
15、timately be determined by corrosion creep-back of scribed paint panels. Regions may determine based upon their specific materials, cleaning systems, paint processes, and the maximum level of surface carbon that is acceptable. 3.2 Surface Roughness. The arithmetic average (Ra) surface roughness and p
16、eak count (RPc) measured on flat, unformed panels, are shown for steel in Table 2 and aluminum in Table 3. Manufacturing locations not listed in the following tables shall use the surface roughness and peaks per centimeter (cm) requirements from one of the regions listed. Table 2: Surface Roughness
17、and Peaks/cm Requirements for Sheet Steel Surface Roughness (Ra) Surface Type North America Note 1 Europe Note 2 Brazil Note 3 China Note 1 Korea Note 1 Exposed (E) 0.5 m to 1.3 m 1.1 m to 1.6 m 0.7 m to 1.5 m 0.5 m to 1.3 m 0.7 m to 1.3 m Semi-exposed (Z) dull finish 0.5 m to 1.3 m Not applicable 0
18、.7 m to 1.5 m 0.5 m to 1.3 m Not applicable Unexposed (U) Not required 1.1 m to 1.7 m Not required Not required Not required Peaks/cm (RPc) Surface Type North America Note 1 Europe Note 2 Brazil Note 3 China Note 1 Korea Note 1 Exposed (E) 40 60 40 40 40 Semi-exposed (Z) dull finish 40 Not applicabl
19、e 40 40 40 Unexposed (U) Not required 50 Not required Not required Not required Note 1: As measured by SAE J911. Ra and RPc shall be measured using a 0.8 mm filter cutoff with the appropriate traverse length as listed in SAE J911 for the type of instrument used for the measurement. Exposed and Semi-
20、exposed surfaces (E and Z grade) with an Ra roughness within the above range are acceptable if the observed Peak Count (RPc) exceeds 40 using a 1.25 m measurement band for determining peaks per centimeter (PCcm). Note 2: As measured by EN 10049. All Cold rolled products shall be temper rolled. Note
21、3: As measured by EN 10049. 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 GMW16823 Copyright 2012 General Motors Company All Rights Reserv
22、ed November 2012 Page 3 of 6 Table 3: Surface Roughness and Peaks/cm Requirements for Aluminum Sheet Surface Roughness (Ra) Surface Type All Regions Except Europe Note 1 Europe Note 1 Exposed, E, EDT 0.7 to 1.3 m 0.7 to 1.3 m Exposed, E, MF Note 2 0.3 to 0.6 m 0.3 to 0.6 m Unexposed, U, EDT Note 2 0
23、.7 to 1.3 m 0.7 to 1.3 m Unexposed, U, MF 0.3 to 0.6 m 0.3 to 0.6 m Peaks/cm (RPc) Surface Type All Regions Except Europe Note 1 Europe Note 1 Exposed, E, EDT 40 50 Exposed, E, MF Note 2 40 Not required Unexposed, U, EDT 40 40 Unexposed, U, MF Note 2 Not required Not required Note 1: Aluminum surfac
24、e roughness may be measured by a non-contact surface metrology system, or a scanning interferometer system, or with a contact profilometer. 1, as defined in EN 10049. Note 2: For Europe, a mill finish (MF) is required. 3.2.1 Exposed (E) surface shall be free from scratches, mill marks, dross, and an
25、y other steel making or processing defects detrimental to a Class A finish. This finish is applicable to bare and coated products. Exposed surface shall be processed as the “prime” side only. 3.2.2 Semi-exposed (Z) or “dull” surfaces cannot contain scratches, dross, or any other steel making or proc
26、essing defects detrimental to Class B finish. This surface is only applicable for a temper rolled, spangle free, hot dip free zinc product. 3.2.3 Unexposed (U) surface may be bare or coated and is to be used for Class C and/or Class B finishes. Surface defects detrimental to the part (lamination, fl
27、aking of zinc, excessive surface carbon, etc.) are not allowed. The maximum spangle size for hot dip free zinc product is 6 mm. 3.2.4 Temper Passed (T) surfaces have been temper-passed to impart a minimum surface roughness and to eliminate surface defects such as Leuders lines. 3.3 Surface Treatment
28、s. The application of most surface treatments, with the exception of pre-phosphate coatings, nickel flashing, passivation and chromate coatings, are generally not allowed on steel or aluminum surfaces. If a Ti/Zr passivation layer is required for aluminum sheet, the passivation layer composition and
29、 coating weight will be determined by the local Materials Engineering organization. All aluminum sheet supplied in Europe shall have a Ti/Zr passivation layer according to the Lastenheft. The passivation layer shall be applied on both surfaces according to the following: Conversion Film (Europe Only
30、): Gardobond X 4591 (Chemetall) Layer weight mg/m on each side 4 Ti 8 4 Zr 8 3.4 Surface Applied Lubricants and Conversion Coatings. Specific Requirements for lubrication, phosphate and thin film treatments required for painting are covered in GMW16546, GMW3011 and GMW16170. 3.5 Marking. If required
31、, marking shall be carried out on the unexposed surface of full finish coils for outer panels and on the outer side of the coils for inner panels. The marking must be agreed upon between the supplier and purchaser. The purchaser must release the marking ink. 4 Manufacturing Process Not applicable. C
32、opyright 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 GMW16823 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 4 of 6
33、5 Rules and Regulations 5.1 Legal Regulations. All materials must satisfy applicable laws, rules, regulations and recommendations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall take precedence. 5.3 Inspectio
34、n and Rejection. Samples of components or materials released to a GM material specification shall be tested for conformity with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk supplies. A new approval mu
35、st be received for any changes, e.g., properties, manufacturing process, location of manufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, w
36、ithout solicitation, and to include documentation of all modifications of materials and/or processes and to apply for a new release. If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior to commencement of delivery of non-conforming bulk supplies. In indiv
37、idual cases, a shorter test can be agreed to between the responsible Engineering department and the supplier. All shipments of material or parts under contract or purchase order manufactured to this specification shall be equivalent in every respect to the initial samples approved by Engineering. Th
38、ere shall be no changes in either formulation or manufacturing processes permitted without prior notification and approval by Engineering. Lack of notification by the supplier constitutes grounds for rejection of any shipment. While samples may be taken from incoming shipments and checked for confor
39、mance to this specification, the supplier shall accept the responsibility for incoming shipments meeting this specification without dependence upon purchasers inspection. The series of tests used to approve each batch of product along with acceptance limits will be agreed upon by the purchaser and s
40、eller. The laboratory providing the certificate of analysis must also participate in a proficiency testing program (round robin) that is approved by the Ferrous Materials and Sheet Metals Global Subsystem Leadership Team (GSSLT) or designate. Ferrous Materials and Sheet Metals or designate must rece
41、ive copies of the proficiency testing reports directly from the test program administrator. 5.4 Material Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occurred, a complete copy of the Material Safety
42、 Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions must be in compliance with specific country Gene
43、ral Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available. 5.5 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources Materials supplied to this specification mus
44、t be approved by General Motors. The appropriate GM Materials Engineering department(s) must confirm material as meeting the requirements of this specification. Any test data sheets of material submitted to General Motors for such confirmation (e.g., during Production Part Approval Process (PPAP) un
45、der this material specification must list all properties and must apply corresponding test methods of this material specification. 7 Notes 7.1 Glossary. MATSPC: Global repository of GM approved materials for corresponding GM Engineering Standards. Ra: Arithmetic Average Surface Roughness RPc: Peak C
46、ount of Surface Roughness (peaks/cm) 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 GMW16823 Copyright 2012 General Motors Company All Righ
47、ts Reserved November 2012 Page 5 of 6 7.2 Acronyms, Abbreviations, and Symbols. E Exposed EDT Electric Discharge Texture GHS Globally Harmonized System of Classification and Labeling of Chemicals GSSLT Global Subsystem Leadership Team MF Mill Finish MSDS Material Safety Data Sheet PCcm Peaks per Cen
48、timeter PPAP Production Parts Approval Process R&R Repeatability and Reproducibility RPc Roughness and Peak Count SDS Safety Data Sheet T Temper Passed U Unexposed Z Semi-exposed 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Material per GMW16823 9
49、 Release and Revisions This standard was originated in June 2012. It was first approved by the Ferrous Metals GSSLT in November 2012. It was first published in November 2012. Issue Publication Date Description (Organization) 1 NOV 2012 Initial publication. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted wi
