1、NAVISTAR, INC. CEMS (CORPORATE ENGINEERING MATERIAL SPECIFICATION)NUMBER: CEMS A-40, SEC A TITLE: Case Hardened Iron And Steel Parts Carburizing and Carbonitriding CURRENT ISSUE DATE: October 2008 WRITTEN/REVIEWED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES ISSUE OF: Octo
2、ber 2001 PRINTED 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 appropriat
3、e safety and health practices and to determine the applicability of regulatory limits prior to use. Change Notice: Replaced “International Truck and Engine Corporation” with “Navistar, Inc.” per corporate directive; added CEMS B-50 requirement; revised Section 6.4.1; editorial changes. 1.0 SCOPE CEM
4、S A-40, covering case hardened iron and steel parts, is in two sections: Section A Carburizing and Carbonitriding Section B - Aerated Salt Nitriding And Gaseous Ferritic Nitrocarburizing CARBURIZING AND CARBONITRIDING 2.0 INTRODUCTIONThis specification covers the Companys requirements for the proper
5、ties of hardened case produced by the diffusion of carbon or carbon and nitrogen into the surface of steel parts. All properties shown refer to finished parts. 2.1 Restricted Chemical Substances Effective January 1, 2007, all product supplied to the requirements of this specification must comply wit
6、h the requirements of the CEMS B-50 specification. 3.0 CONTENTSPAGE REFERENCE DOCUMENTS 2 GENERAL REQUIREMENTS 2 QUALITY 4 METHODS OF TEST 4 SOURCE APPROVAL AND QUALITY CONTROL 6 DESIGNATION ON DRAWINGS AND PURCHASE ORDERS 6 PACKING AND SHIPPING 7 APPENDIX Green SheetsThis document is restricted and
7、 may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. OCTOBER 2008 Page 1 of 7 Copyright Navistar International Corporation Provided by IHS under license with INTERNNo
8、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: TITLE: CURRENT ISSUE DATE: CEMS A-40A Case Hardened Iron And Steel Parts October 2008 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Techni
9、cal Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. 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 specification. Qua
10、lity System Standard ISO 9001 or TS-16949 SAE J 864 CFR Title 29, Part 1910 CEMS B-50 NAVISTAR Manufacturing Standard MS-D-13 CEMS A-0, Part II SAE J1081 SAE J404 5.0 CLASSIFICATION Case hardened steels are classified by the depth of the hardened surface layer. See Tables I and II. 6.0 GENERAL REQUI
11、REMENTS6.1 Light Cases Light cases have depths of 0.020 inch (0.50 mm) or less. The case depth will be measured by the total case method, unless otherwise specified. Classification, requirements, and case hardening process will be as shown in Table I (refer to Section 6.5 for measurement of case pro
12、perties). See also Section B. TABLE I CLASSIFICATION(1)AND REQUIREMENTS(2) (3) Light Cases Total Case Depth Navistar Class in mm Surface Hardness Case Hardening Process Quench 1A File Resistant 1B 0.002-0.006 0.05-0.15 File Hard Carbonitride Oil or Water 2A File Resistant Gas 2B 0.006-0.010 0.15-0.2
13、5 Rockwell 89-93 HR15N or File Hard Carbonitride Oil or Water 3 Rockwell 89-93 HR15N Oil or Water 3A 0.010-0.020 0.25-0.50 File Resistant Carbonitride or Carburize (Liquid or Gas) Gas (1)Where deemed feasible on particular parts and after consultation with the Materials Engineer, more than one Class
14、 should be specified. See “Appendix - General Information” for further discussion. (2)All case-hardened steels shall be produced using fully-killed, fine-grain practices. (3)Heat treating will be carried out in such a manner as to avoid excessive brittleness in the finished part. Parts which require
15、 specific properties will have the requirements and methods of test detailed on the drawing. 6.2 Heavy Cases Heavy cases are those with case depths in excess of 0.020 inch (0.51 mm) and will be produced by carburizing. All heavy case carburized parts will be tempered at 350F (175C) minimum. The effe
16、ctive case depth method will be used for determination of case depth on the tempered part, unless otherwise specified on the engineering drawing. Classification will be as shown in Table II (refer to Section 6.5 for measurement of case properties). 6.3 Surface Hardness Whenever a class from Table II
17、 is specified, it is also necessary to specify the desired surface hardness. For gears and splined shafts, the specified hardness is generally Rockwell 57-63 HRC, while roller bearing components are usually specified Rockwell 60 HRC minimum. For certain applications, it may OCTOBER 2008 Page 2 of 7
18、Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: TITLE: CURRENT ISSUE DATE: CEMS A-40A Case Hardened Iron And Steel Parts October 2008 This document is restricted and may n
19、ot be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2008 by Navistar, Inc. be desirable to specify file hardness. If a surface hardness range with a minimum less than Rockwell 55 HRC is specifie
20、d, special effective case hardness must be designated on the drawing (see Section 10.0). 6.4 Microstructure Surface and near surface microstructures are important to performance. A structure of tempered martensite and austenite which results in a surface hardness of not less than 57 HRC or the minim
21、um specified on the drawing is required. Exceptions are noted below. (Note that retention of a sharp edge on the metallographic section is very important for determination of surface microstructures. Use of wax wheels for polishing or electroless nickel plating of the case hardened surface are sugge
22、sted for edge retention.) TABLE II CLASSIFICATION(1)AND REQUIREMENTS (2) Heavy Cases Effective Case Depth(3)Effective Case Depth(3)Navistar Class(4)inch mm Navistar Class(4)inch mm 25 0.018-0.038 0.40-0.90 60 0.048-0.074 1.25-1.90 30 0.022-0.043 0.50-1.00 70 0.056-0.082 1.50-2.15 35 0.026-0.048 0.65
23、-1.25 80 0.065-0.095 1.65-2.40 40 0.031-0.055 0.75-1.40 90 0.075-0.105 1.90-2.65 45 0.036-0.060 0.90-1.50 110 0.095-0.125 2.40-3.15 50 0.040-0.066 1.00-1.65 130 0.115-0.145 2.90-3.65 (1)Where deemed feasible on particular parts and after consultation with the Materials Engineer, more than one Class
24、should be specified. See “Appendix - General Information” for further discussion. (2)All case-hardened steels shall be produced using fully-killed, fine-grain practices. (3)Case depth measurements on gear teeth will be made at the pitch line and at the root fillet. At the pitch line, the case depth
25、will conform to the specified class; at the root fillet, it will be not less than 50% of the minimum specified class. On critical parts, it is desirable to specify the location for case depth checks since the case depth may vary from one area to another on a single part. (4)For obsolete parts with c
26、onventional (total) case depth specified on the engineering drawing, the relationships between effective and conventional case depths are approximate. Contact Materials Engineering for conversion of the obsolete case depth to one of the Navistar Classes shown in Table II. 6.4.1 Only well-distributed
27、 globular carbides are permitted. 6.4.2 Limited amounts of intergranular oxides or associated transformation products are allowed, but to a depth no greater than 0.001 inch (25mm). Where performance requires no intergranular oxides or associated transformation products, this should be specified on t
28、he part drawing. 6.4.3 While bainite in the case is not desired, a small amount is permissible providing the minimum surface hardness of 57 HRC is maintained. 6.5 Measurement Of Case Properties 6.5.1 Location Of Measurement Measurement will be made on one or more significant surfaces of the finished
29、 part. Case depth measurements on gear teeth will be made at two locations: (1) the pitch line, and (2) the root fillet, both OCTOBER 2008 Page 3 of 7 Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without l
30、icense from IHS-,-,-NUMBER: TITLE: CURRENT ISSUE DATE: CEMS A-40A Case Hardened Iron And Steel Parts October 2008 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 li
31、ability. 2008 by Navistar, Inc. on a plane midway between the ends of the tooth. Due to the difficulty of locating the theoretical pitch line, this position will be considered to be approximately midway between the tip and the root, on a line perpendicular to a line tangent to the surface, as shown
32、in the following figure. The root fillet measurement will be made on a line aproximately 45 degrees to the centerline of the tooth cross section and per- pendicular to a line tangent to the root fillet at the point of tangency. This position approximates the location of the maximum bending stress. P
33、itch Line Traverse Root Fillet Traverse dd_ 27.0 QUALITY All product supplied shall be clean and free from dirt, oils, sharp edges, or defects harmful to product performance. The supplier should be capable of providing statistical evidence that the product has been manufactured within process contro
34、l limits established by the supplier for the product and that the process s capable of meeting all requirements of this specification. i8.0 METHODS OF TEST 8.1 Methods of Measurement 8.1.1 Total Case Depth Measure at a magnification of 100 diameters on a suitably polished and etched section perpendi
35、cular to the significant surface using a micrometer ocular calibrated to read in thousandths of an inch (hundredths of a mm), or other suitable device, recording average depth to core structure. 8.1.2 Effective Case Depth Make a series of microhardness impressions across the case on a polished and u
36、netched section perpendicular to the significant surface, using a properly calibrated microhardness tester with a Knoop penetrator or other suitable tester. The longitudinal axes of the impressions will be parallel to the surface. Space the microhardness impressions so that they are not distorted by
37、 adjacent impressions or by the surface. Using loads of 500 or 1000 grams force, spacings of 0.005 inch (0.13 mm) have been found satisfactory. Closer spacing may be obtained, if necessary, by two or more traverses of impressions at staggered distances from the surface. 8.1.2.1 When the desired trav
38、erse has been completed, measure the length of each impression, determine the Knoop hardness number, then convert to the nearest whole number of the Rockwell C scale using the conversions listed in Table III. Plot the hardness values against their depth from the surface and draw a curve approximatel
39、y connecting the points. Determine the depth at which the curve crosses the Rockwell 50 HRC hardness level. This is effective case depth. OCTOBER 2008 Page 4 of 7 Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitt
40、ed without license from IHS-,-,-NUMBER: TITLE: CURRENT ISSUE DATE: CEMS A-40A Case Hardened Iron And Steel Parts October 2008 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 a
41、ll patent liability. 2008 by Navistar, Inc. TABLE III - HARDNESS CONVERSIONS KNOOP ROCKWELL C KNOOP ROCKWELL C KNOOP ROCKWELL C251 20 380 38 650 56256 21 391 39 670 57 261 22 402 40 690 58266 23 414 41 710 59 272 24 426 42 732 60278 25 438 43 754 61 284 26 452 44 776 62290 27 466 45 799 63 297 28 48
42、0 46 822 64304 29 495 47 846 65 311 30 510 48 870 66318 31 526 49 895 67 326 32 542 50 920 68334 33 558 51 342 34 576 52351 35 594 53 360 36 612 54370 37 630 55 8.1.3 Other Methods Of Case Depth Measurement For production control, it may be necessary to use other methods for measuring case depth, at
43、 the discretion of the producer. However, it is the producers responsibility to establish correlation between the method employed and the methods specified above. Since this specification refers only to case depth of finished parts, it may be necessary to produce cases deeper than those specified he
44、rein to compensate for stock removed during grinding or other manufacturing processes. 8.1.4 File Hardness A Pillar No. 1 or No. 0 hardness testing file with a hardness of Rockwell 64-65 HRC will be considered the Companys standard hardness testing file. Securely hold the part to be tested, preferab
45、ly in a vise. With one hand at each end of the file, place a sharp portion of the flat of the file (not an edge) on the surface to be tested, pressing firmly forward and downward simultaneously. If the file tends to slide easily across the surface, the surface is considered “file hard.” If the file
46、tends to bite or cut only with difficulty, the surface is considered “file resistant.” If the file cuts easily, it is “file soft.” In no case will the file be rubbed back and forth over the surface, since this tends to rapidly dull a large portion of the files teeth. Discard the file when no usable
47、sharp areas remain. For a more detailed description of the file test, see SAE J864. 8.1.4.1 CAUTION: At best, file hardness testing is an inexact art, not an exact science, since much depends upon the skill and judgment of the person making the test. Yet under proper conditions, it may be used satis
48、factorily to compare the surface hardness of the part being tested with that of a known standard. OCTOBER 2008 Page 5 of 7 Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: TITLE: CURRENT ISSUE DATE: CEMS A-40A Case Hardened Iron And Steel Parts October 2008 This document is r
