1、This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2017 by Navistar, Inc. OCTOBER 2017 Page 1 of 7 NAVISTAR, INC. Material, Parts, and Process Specification
2、s (MPAPS) NUMBER: MPAPS G-20 Former Designation: CEMS G-20 TITLE: Zinc Plating CURRENT Rev. No.: 1710 DATE: Oct. 2017 WRITTEN/REVIEWED BY: J. Goldschmidt APPROVED BY: R. Goluch SUPERSEDES: 1608 August 2016 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION This specification may i
3、nvolve hazardous materials, equipment, and procedures. This specification does not purport to address all of the safety issues associated with its use. The user is responsible to consult appropriate safety and health practices and to determine the applicability of regulatory limits prior to use. 1.0
4、 SCOPE This specification covers Navistars requirements for electrodeposited zinc coatings on iron and steel substrates. Provision is also made to specify mechanical plated zinc coatings by the addition of a suffix “M” to the class designation. 2.0 INTRODUCTION Zinc plating is used primarily for cor
5、rosion resistance. This specification provides for several classes of zinc plating for use on both Engineering designed parts and Engineering Standard Parts. Typical parts include clips, clamps, brackets, small stampings, tubes, rivets, rivnuts, lock bolt collars, screws, bolts and nuts, washers, an
6、d fittings. Zinc plated parts or their corrosion products must not come in contact with stressed polyamides (nylon 6 or 66) or PTFE (e.g., ball joints/raceways). 2.1 Restricted Chemical Substances Effective January 1, 2007, all product supplied to the requirements of this specification must comply w
7、ith the requirements of the MPAPS B-50 specification. 3.0 CONTENTS PAGE REFERENCE DOCUMENTS 1 CLASSIFICATION 2 GENERAL REQUIREMENTS 2 QUALITY 4 METHODS OF TEST 5 SOURCE APPROVAL AND QUALITY CONTROL 5 DESIGNATION ON DRAWINGS AND PURCHASE ORDERS 6 PACKING, SHIPPING AND IDENTIFICATION 6 TECHNICAL INFOR
8、MATION 6 NOTE: All product supplied to the requirements of this specification must be free of hexavalent chrome. NUMBER: MPAPS G-20 TITLE Zinc Plating REVISION: 1710 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Stand
9、ards. Suppliers are required to assume all patent liability. 2017 by Navistar, Inc. OCTOBER 2017 Page 2 of 7 4.0 REFERENCE DOCUMENTS Unless otherwise specified, the latest issue of all referenced standards shall apply. The following standards, specifications and regulations are referenced in this sp
10、ecification: Quality System Standard ISO 9001 or TS-16949 NAVISTAR D13 - Supplier Packing and Shipping Standard CFR Title 29, Part 1910 NAVISTAR MPAPS B-50 Restricted Chemical Substances NAVISTAR MPAPS GT-Paint Paint Test Methods ASTM B117 - Practice for Operating Salt Spray (Fog) Apparatus ASTM B20
11、1 - Practice for Testing Chromate Coatings on Zinc and Cadmium Surfaces ASTM B487 - Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section ASTM B499 - Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatin
12、gs on Magnetic Basis Metals ASTM B633 - Specification for Electrodeposited Coatings of Zinc on Iron and Steel ASTM B695 - Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel ASTM D6492 - Practice for Detection of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated Stee
13、l 5.0 CLASSIFICATION Zinc plating is classified by coating thickness and level of corrosion resistance, as described in Table 1 below. 6.0 GENERAL REQUIREMENTS Parts to be plated will be thoroughly cleaned and free of rust, scale, oil and other foreign matter. The cleaning operation must be controll
14、ed to prevent hydrogen embrittlement, especially in those parts that are hardened, cold worked, or subject to high service stresses. In the case of high strength, high hardness parts (see Section 7.1), mechanical plating (ASTM B695) may be preferred since relief of hydrogen embrittlement may be diff
15、icult to achieve. In this case, mechanical zinc plating will be specified on the engineering drawing by the addition of an “M” suffix to the Class designation (example: Class 8AM, etc.). 6.1 Plating Requirements 6.1.1 Passivation Treatments Zinc plating should always be given a passivating treatment
16、 to prevent the occurrence of white (zinc) corrosion products, unless there is a specific reason for the omission of this treatment. Hexavalent chromate conversion coatings are not permitted on zinc-plated parts supplied to Navistar or for parts used in Navistar products. The coating classes reflect
17、ed in Table 1 below assume use of trivalent chromium passivation or other hex-chrome free conversion coating. Requirements for each class of coating are shown below. 6.1.2 Zinc Plating and Paint Since some of the plating classes may require an additional sealer/topcoat over the zinc plating in order
18、 to achieve the required performance, this may not be desirable if plated parts will be subjected to further painting operations, such as chassis paint. In such cases, with prior approval from Engineering or Materials Engineering, the performance specified in the table may be waived and the acceptan
19、ce criteria for the given class will be based on the plating thickness rather than salt spray performance or as specified on the engineering drawing or purchase order. NUMBER: MPAPS G-20 TITLE Zinc Plating REVISION: 1710 This document is restricted and may not be sent outside Navistar, Inc. or repro
20、duced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2017 by Navistar, Inc. OCTOBER 2017 Page 3 of 7 6.1.3 Transmission Oil Cooler Tubing Class 6A will be specified on drawings for transmission oil cooler (TOC) steel tubing/assemblies. I
21、n this application, a minimum plating thickness of 4 microns will be allowed as long as the salt spray performance is demonstrated to meet a minimum of 24 hours to white corrosion and 96 hours to red rust on formed areas of tubes. Exceptions to this requirement may be specified on the engineering dr
22、awing. Table 1 CLASSIFICATION AND REQUIREMENTS Navistar Designation Min. plating thickness Neutral Salt Spray Test (ASTM B117) Class* Obsolete Class Approximate ASTM B633 Service Condition Equivalent m in. White Corrosion (hours of test) Red Rust (hours of test) Sealer Appearance 12A 12B, 13A/B, A,
23、AC SC3 (severe) 12 0.0005 120 360 Optional Clear/silvery color 8F1,2 - SC2 (moderate) 8 0.0003 240 480 Required Clear/silvery color 8A 8B SC2 (moderate) 8 0.0003 120 240 Optional Clear/silvery color 6A 6B, 5A/B, 3A/B SC1 (mild) 6 0.0002 48 96 Optional Clear/silvery color 1 - A flash deposit for iden
24、tification, coloring, or temporary protection from corrosion while in transit. Not Allowed Clear; passivation not required 1 Class 8F includes application of a post-plating sealer (dip solution) for added abrasion resistance and corrosion protection for fasteners. This class would be recommended for
25、 use on heavy duty fasteners (such as hex bolts) which would not be subjected to further painting operations. It is not recommended for smaller parts, such as screws. Use of Class 8F for a given part must be specified on the engineering drawing or in the applicable Engineering Standard Parts specifi
26、cation. Also, no torque-tension fluid or wax (in addition to any sealer) will be added to a given part unless specified on drawing or unless approved by NAVISTAR Fastener Engineering. 2 For nylon insert locknuts, compatibility of sealer with nylon must be verified and reported. *Mechanical zinc plat
27、ing will be specified on the engineering drawing by the addition of an “M” suffix to the Class designation (e.g., Class 8AM, etc.). See paragraph 6.1.3 above for Transmission Oil Cooler lines. 6.2 Appearance and Color of Plated Parts In the past, when use of hexavalent chromate passivation was used
28、on zinc plating, plated parts commonly exhibited a yellow iridescent coating appearance. However, that appearance was a function of that type of process, but zinc plating with trivalent chrome passivation is a clear/bright/silvery color. Provision of a yellow color (or other colors) in trivalent pas
29、sivation coatings can only be achieved with the addition of a color dye. Unless a specific color is designated on the drawing or purchase order, the clear/bright/silvery color will be provided. Note that the addition of a color dye could possibly reduce corrosion performance. NUMBER: MPAPS G-20 TITL
30、E Zinc Plating REVISION: 1710 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2017 by Navistar, Inc. OCTOBER 2017 Page 4 of 7 6.3 Corrosion Performance P
31、arts plated according to the requirements of this specification will be capable of withstanding neutral salt spray testing for the required minimum number of hours for the plating class designated in Table 1. Acceptable corrosion performance is defined as having no white corrosion or red rust after
32、the specified hours of test. Significant surfaces for evaluation of fasteners will be defined as all exposed surfaces of fastener(s) when installed, including but not limited to fastener heads, socket recesses, SEMS washers, and external surfaces of nuts. Threads and points are excluded unless other
33、wise specified on drawing. On parts other than threaded fasteners, significant surfaces will include all plated surfaces; deep recesses, blind holes, edges, and tubing interiors are excluded unless otherwise specified on drawing. 6.4 Plating Thickness Thickness of zinc plating on parts supplied to t
34、his specification shall meet the minimum plating requirements for the applicable class as specified in Table 1. Maximum thickness on threaded parts will be twice the minimum specified plating thickness, and is limited by the basic thread size and its associated tolerances. Coated fasteners must pass
35、 all appropriate Thread Go gages for thread sizing. Threads may be produced undersized prior to plating providing that the finished threaded part meets all mechanical property requirements specified for the part. While there is no defined maximum plating thickness for components other than fasteners
36、, excessive thickness can interfere with adhesion and corrosion performance, and should be avoided. For plating having supplementary treatments (e.g. sealers), plating thickness values apply after application of treatment. Plating thickness will not include other treatments such as oils, waxes, etc.
37、 6.5 Adhesion Plating on parts will not blister, chip or flake after adhesion testing as described in Section 8.3. 6.6 Paintability Zinc plated parts must be compatible with plant paint systems. They shall provide good adhesion to chassis paint and must meet minimum 90% adhesion level when tested to
38、 MPAPS GT-PAINT Method 5A. 7.0 QUALITY The zinc coating will be dense and uniform, free from porosity, pinholes and blisters, and substantially free from other defects that may affect the appearance or protective value of the coating. The plating will have no gray or burned area and will not flake o
39、ff or develop “spotting out.” 7.1 Hydrogen Embrittlement All steel parts having core hardness greater than 32 HRC or surface hardness of 35 HRC, as well as all highly stressed cold worked parts subsequently electroplated with zinc, are subject to embrittlement because of hydrogen absorption. For ele
40、ctroplated zinc parts such as these, it will be the responsibility of the supplier to ensure that supplied parts are free of hydrogen embrittlement and to see that such parts are baked within one hour of electroplating (but before any supplementary coatings are applied) to relieve hydrogen embrittle
41、ment. Generally, the bake operation will involve heating in an oven until the part core NUMBER: MPAPS G-20 TITLE Zinc Plating REVISION: 1710 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are requi
42、red to assume all patent liability. 2017 by Navistar, Inc. OCTOBER 2017 Page 5 of 7 temperature (not oven temperature) reaches 205-215C (400-420F), and holding at this temperature for 4 hours minimum. Likewise, hardened parts which have been tempered at less than 175C (350F) should be heated at 150C
43、 (300F) for at least 8 hours. If the part to be plated is considered susceptible to failure because of hydrogen embrittlement, mechanical zinc plating may be specified on the engineering drawing by the addition of an “M” suffix to the Class designation (e.g., Class 8AM, etc.). 7.2 Arc Burns Arc burn
44、s, resulting from poor or intermittent electrical contact between the workpiece and the power supply, are not permitted. 7.3 Sampling Procedure Select for test one or more random samples from each shipment, or from authorized test specimens. The number of samples to be selected from each size lot wi
45、ll be agreed upon between the supplier and the purchaser. If results fall below the test requirements, the shipment may be rejected. 8.0 METHODS OF TEST 8.1 Plating Thickness Determine thickness of coating on significant surfaces (see Section 6.3 for definition) using the eddy current (magnetic) met
46、hod (ASTM B499), the x-ray method, or the microscopic method (ASTM B487). The microscopic method will be used as a referee test when necessary. 8.2 Salt Spray Testing Perform salt spray testing per ASTM B117. 8.3 Plating Adhesion Sample plated parts will be exposed to 220C for 30 minutes, followed b
47、y quenching in water at room temperature. 8.4 Passivation Treatment Presence of a hex-free chromate coating may be verified per certification by the plater. When necessary for referee purposes, presence of clear chromate coatings may be determined per ASTM B201. The absence of hexavalent chrome may
48、be demonstrated using ASTM D6492, as required. 9.0 SOURCE APPROVAL AND QUALITY CONTROL 9.1 Supplier Requirements All suppliers to NAVISTAR are required to be registered to ISO 9001 Quality System Requirements. NAVISTAR will also accept TS-16949 registration as long as the supplier can also fulfill all AIAG PPAP (Production Part Approval Process) documentation and approval requirements. Suppliers must maintain their certification with an accredited registrar and must furnish copies of registration certificates to their Corporate Buyer upon request. NUMBER: MPA
