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. 2014 by Navistar, Inc. DECEMBER 2014 Page 1 of 6 NAVISTAR, INC. Material, Parts, and Process Specificatio
2、ns (MPAPS) NUMBER: MPAPS G-19 Part II Former Designation: CEMS G-19 Part II TITLE: : Electrodeposited Engineering (Hard) Chromium Coatings CURRENT REV No.: 1412 DATE: Dec. 2014 WRITTEN/EDITED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES: CEMS G-19 Pt II April 2002 PRINTED
3、COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION This specification may involve 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 heal
4、th practices and to determine the applicability of regulatory limits prior to use. Change Notice: Changed to new MPAPS spec format; extensive revision, editorial changes. 1.0 APPLICATION 1.1 Engineering coatings of chrome plate are generally used to increase the surface hardness of a part or to impr
5、ove its wear resistance 1.2 Chromium plate is hard and dense with good corrosion resistance to most materials. It has a lower friction coefficient than any other metal and good anti-galling properties as long as it is not used against itself. Despite its hardness, it should not be used as a general
6、substitute for hardening but only when properly engineered for this purpose. It may be applied to aluminum, copper, steel and cast iron substrates. 1.3 Hard chromium, as differentiated from decorative chromium, is applied for functional reasons regardless of thickness. If a 0.00005 inch (1.3 m) depo
7、sit is applied to a surface, its apparent hardness will reflect that of the basis metal. If, however, a 0.0015-.0020 inch (38-51 m) deposit is applied over an unhardened part, it will be hard. In short, a deposit of over 0.001 inch (25 m) is essential before chromium will assume its true hardness ch
8、aracteristics when applied to unhardened basis metals, whereas over a hardened base, this thickness is not necessary because of the substantial backing provided. 2.0 SCOPE This specification covers the basic requirements for electrodeposited hard chromium as used to meet service conditions involving
9、 wear, corrosion, friction or a combination of these. 2.1 Restricted Chemical Substances Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the MPAPS B-50 specification. 3.0 REFERENCE DOCUMENTS Unless otherwise specified, th
10、e latest issue of all referenced standards shall apply. The following Specifications, Standards, and Regulations are referenced in this specification. Quality System Standard ISO 9001 or TS-16949 ASTM B177 ASTM B499 NAVISTAR Engineering Design Std A-16 ASTM B117 ASTM B504 NAVISTAR Manufacturing Std.
11、 MS-D-13 ASTM B456 ASTM E384 NAVISTAR MPAPS B-50 ASTM B487 ASTM B650 CFR Title 29, Part 1910 ASTM B242 ASTM B183 ASTM B322 ASTM B253 ASTM B281 NUMBER: MPAPS G-19 Part II TITLE: Electrodeposited Engineering (Hard) Chrome Coatings REVISION: 1412 This document is restricted and may not be sent outside
12、Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2014 by Navistar, Inc. DECEMBER 2014 Page 2 of 6 ASTM B242 ASTM B254 ASTM B320 ASTM B578 ASTM B571 ASTM B849 ASTM F519 ASTM B850 ASTM B851 4.0 REQUIREMENTS Three
13、 classes of plating for engineering applications are provided for in this specification as shown in the table below: Class Resistance to Typical Applications Chromium Thickness * Adhesion Test Porosity Test wear corrosion mils m DS excellent good Pump shafts, Hyd. Piston rods 1.00 min 25 min Pass Pa
14、ss 1.50 avg 38 avg ES good good Hyd. Piston rods 0.40 to 0.80 10 to 20 Pass Pass FS Fair Fair Air valves 0.25 min 6 min Pass Not required 0.35 avg 9 avg *Production parts, when required, will be produced undersize to allow for the plating thickness shown in above table. They will then be plated to m
15、eet specified size requirements. 4.1 Surface Preparation 4.1.1 Cleaning The articles to be plated will be thoroughly cleaned and free from rust, scale, oil and other foreign matter detrimental to the final finish as recommended in ASTM B177. The surface will have a sufficiently fine finish to assure
16、 the desired final plating quality. Parts to be electroplated may be cleaned in accordance with ASTM Practices B183, B254, B242, B281, B320, B322, B481, B558 or B630 or Guide B253. 4.1.2 Hydrogen Embrittlement The cleaning on ferrous operation will be controlled to prevent hydrogen embrittlement, es
17、pecially in those parts that are hardened, cold worked or subject to high service stresses. 4.1.3 Stress Relief High strength/high hardness steel parts that are subjected to machining, grinding, cold forming or cold straightening after heat treatment are particularly susceptible to hydrogen absorpti
18、on. Therefor such parts should be stress relieved prior to cleaning and plating per ASTM B849. 4.1.4 Shot Peening Parts for which fatigue life after plating will benefit from compressive residual surface stresses may be shot peened per ASTM B851. 4.2 Thickness The thickness of plating is shown in th
19、e table above. Measurements will be made on significant surfaces. These are defined as those that can be touched with a 0.75 inch (19 mm) diameter ball. This definition may be superseded by notations on the engineering drawing. 4.3 Hardness The hardness of the plating will be 800 VHN minimum. As a r
20、outine check, engineering chromium should be file hard. NUMBER: MPAPS G-19 Part II TITLE: Electrodeposited Engineering (Hard) Chrome Coatings REVISION: 1412 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Sup
21、pliers are required to assume all patent liability. 2014 by Navistar, Inc. DECEMBER 2014 Page 3 of 6 4.4 Adhesion The coating will be sufficiently adherent to the basis metal to pass an adhesion test appropriate to the subject part selected from methods described in paragraph 5.1.3 below. 4.5 Porosi
22、ty The coating will meet the requirement for porosity when tested by one of the methods specified in paragraph 5.1.4. When no special porosity requirement is specified by the purchaser, maximum porosity will be 6 spots per 12 in2 (77.5 cm2) or 2 spots in any square inch (6.5 cm2) of significant surf
23、ace. No pore will be larger than 0.04 inches (1.0 mm) in diameter. 5.0 QUALITY The plate will be hard, smooth, adherent and plated in the bright range. Normally, the appearance of the engineering plate is secondary; however, when a particular finish is desired it will be agreed upon between the supp
24、lier and purchaser. 5.1 Methods of Test 5.1.1 Hardness The Vickers hardness number (VHN) will be determined according to ASTM B578 and ASTM method E384. Where possible the loading selected will not produce an impression with a diagonal longer than 67% of the thickness of the chromium layer. The hard
25、ness report in addition to the VHN will state the test load and the loading time, if other than 10 to 15 seconds. In measuring the hardness of chromium, the preferred procedure is to take the indentation on a polished cross section. Corners of the indentation should be examined carefully for crackin
26、g and if cracks are present, the indentation should be discarded. 5.1.2 Thickness The thickness of the chromium will be measured by one of the following methods: 5.1.2.1. Microscopic Method, ASTM B487 5.1.2.2. Magnetic Method, ASTM B499 5.1.2.3. Coulometric Method, ASTM B504 5.1.3 Adhesion No univer
27、sally satisfactory test for adhesion of chromium is known. Poor adhesion may be revealed during grinding. For the purposes of this specification, the plating must pass either the file or the quenching test unless another test method is specified by the purchaser. These tests are described in the AST
28、M B571. The test selected will depend upon the size, shape or thickness of the part. 5.1.4 Porosity Test for porosity using one of the following methods: 5.1.4.1 MN-Porotest Paper - Moisten test paper with distilled water. Apply wet paper to the degreased metal surface for 10 minutes. Test paper is
29、distributed in the United States by: Gallard-Schlesinger Chemical Mfg. Corporation, 584 Mineola Avenue, Carle Place, L.L., N.Y. 11514 - Stock Number M9680. 5.1.4.2 Ferroxyl - Conduct according per method described in Appendix A.2. Observe after 10 minutes. 5.1.4.3 Neutral Salt Spray - Conduct accord
30、ing to ASTM B117. Observe after 16 hours. NUMBER: MPAPS G-19 Part II TITLE: Electrodeposited Engineering (Hard) Chrome Coatings REVISION: 1412 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are req
31、uired to assume all patent liability. 2014 by Navistar, Inc. DECEMBER 2014 Page 4 of 6 6.0 QUALIFICATION Engineering qualification of sources is required in advance of production shipments. Suppliers shall submit samples for approval of finish, luster, color and appearance to the Navistar Industrial
32、 Design Group. Samples shall be accompanied by test data certifying that all requirements of the specification have been met. Upon approval, styling master samples denoting the minimum level of acceptable appearance quality shall be developed and retained by the supplier and the quality department o
33、f each using NAVISTAR facility. 6.1 Quality Control Plan A Quality Control Plan for products supplied to the requirements of this specification will be established by mutual agreement between NAVISTAR and the supplier. Unless specific exception is noted, the following characteristics, where applicab
34、le*, shall be included in the plan as features for management by statistical process control.* * Other characteristics for inclusion in the control plan may be specified on the engineering drawing and/or purchase order. * See NAVISTAR Engineering Design Standard A-16 7.0 SOURCE APPROVAL AND QUALITY
35、CONTROL 7.1 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 requ
36、irements. Suppliers must maintain their certification with an accredited registrar and must furnish copies of registration certificates to their Corporate Buyer upon request. 7.2 Approval Parts supplied against contracts or purchase orders citing this specification shall be equivalent in all respect
37、s to those samples which were approved by the purchaser. No changes in formulation or processing practices are permitted without approval. In the event that changes in material, properties, processing practices, construction, color, or labeling of the product are required, the supplier shall notify
38、NAVISTAR Materials Engineering and Purchasing and Supplier Development of the proposed change(s). Test data indicating conformance to all requirements of this specification, test samples, and new or amended or updated Material Safety Data Sheet(s) (MSDS), in accordance with CFR Title 29, Part 1910 s
39、hall be submitted with the request for change. 7.3 Process Control The supplier shall either perform and report results of tests on specific lots of parts produced using ISO 9001 or TS-16949 guidelines, or provide statistical evidence of the lot having been produced in a state of statistical control
40、 and with a process capable of providing all required properties. The part supplier and the quality control manager of the using NAVISTAR plant may determine testing and reporting requirements on specific products. Thickness NUMBER: MPAPS G-19 Part II TITLE: Electrodeposited Engineering (Hard) Chrom
41、e Coatings REVISION: 1412 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. 2014 by Navistar, Inc. DECEMBER 2014 Page 5 of 6 8.0 SHIPPING AND HANDLING Ship
42、ping and identification shall be in accordance with NAVISTAR Manufacturing Standard MS-D-13. Parts shall be packaged so as to avoid any damage in shipment detrimental to the appearance of the part. 9.0 DESIGNATION ON DRAWINGS Electroplated chromium coatings will be designated on drawings and purchas
43、e orders as indicated below: Example: Chromium plating, Class DS, MPAPS G-19, Part II 9.1 Hydrogen Embrittlement Susceptible Parts If the part to be plated is considered susceptible to failure because of hydrogen embrittlement, the drawing should specify “must be free from hydrogen embrittlement”. T
44、his is intended to serve as a warning to the plater that the method of cleaning and the baking time and temperature should be carefully considered and controlled. In some applications of industrial plating, it may be desirable to specify an appropriate Stress Relief treatment prior to plating (per A
45、STM B849) as well as embrittlement relief treatment after plating (per ASTM B850). 9.2 Fatigue Life For parts where fatigue life is compromised by chrome plating, an appropriate shot peening treatment should be specified on the drawing per ASTM B851. 10.0 TECHNICAL INFORMATION For further informatio
46、n related to the technical content of this specification, contact: Suppliers may purchase controlled copies of this specification by contacting: Materials Engineering and Technology Dept. 10400 W. North Avenue Melrose Park, IL 60160 E-mail: MaterialsEngineeringN IHS Global Inc. 15 Inverness Way East
47、 Englewood CO 80112-5776 Phone: 1-800-854-7179 E-mail: AutomotiveIHS.com Website: http:/ A.0 GENERAL INFORMATION A.1 Hydrogen Embrittlement Hydrogen embrittlement is a term used to describe a phenomenon that occurs due to absorption of atomic or protonic hydrogen during processing. Steels having ten
48、sile strengths 1000MPa and/or are harder than 300HV10kgf, 303 HB, or 31 HRC, or which are intentionally surface hardened, should be heat treated to reduce the risk of hydrogen embrittlement as described below. Hydrogen embrittlement causes either a loss in load carrying ability or a reduced capacity
49、 for slow plastic strain. Constant load ”delayed fracture” tests are a sensitive means of quantifying the effect. Minute amounts of hydrogen can have major effects. Contrary to the usual effect of embrittlement, effects of hydrogen decrease with increasing strain rate. The phenomenon is most pronounced at intermediate temperatures, but disappears at high and low temperatures. NUMBER: MPAPS G-19 Part II TITLE: Electrodeposited Engineering (H
