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. 2009 by Navistar, Inc. OCTOBER 2009 Page 1 of 7 NAVISTAR, INC. CEMS (CORPORATE ENGINEERING MATERIAL SPECI
2、FICATION) NUMBER: CEMS A-40, SEC A TITLE: Case Hardened Iron and Steel Parts Carburizing and Carbonitriding CURRENT ISSUE DATE: October 2009 WRITTEN/REVIEWED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES ISSUE OF: October 2008 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIE
3、D 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 health practices and to determine the appli
4、cability of regulatory limits prior to use. Change Notice: Corrected Section 6.4.2 depth value from 25mm to 25m. 1.0 SCOPE CEMS 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 Nitr
5、ocarburizing CARBURIZING AND CARBONITRIDING 2.0 INTRODUCTION This specification covers the Companys requirements for the properties 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 Restricte
6、d Chemical Substances Effective January 1, 2007, all product supplied to the requirements of this specification must comply with the requirements of the CEMS B-50 specification. 3.0 CONTENTS PAGE REFERENCE DOCUMENTS 2 GENERAL REQUIREMENTS 2 QUALITY 4 METHODS OF TEST 4 SOURCE APPROVAL AND QUALITY CON
7、TROL 6 DESIGNATION ON DRAWINGS AND PURCHASE ORDERS 6 PACKING AND SHIPPING 7 APPENDIX Green Sheets Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS A-40A TITLE: Case Ha
8、rdened Iron And Steel Parts CURRENT ISSUE DATE: October 2009 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. 2009 by Navistar, Inc. OCTOBER 2009 Page 2 o
9、f 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 specification. Quality System Standard ISO 9001 or TS-16949 SAE J 864 CFR Title 29, Part 1910 CEMS B-50 NAV
10、ISTAR 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 REQUIREMENTS 6.1 Light Cases Light cases have depths of 0.020 inch (0.50 mm) or less. The case
11、 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 properties). See also Section B. TABLE I CLASSIFICATION(1) AND REQUIREMENTS (2) (3) Light C
12、ases Navistar Class Total Case Depth Surface Hardness Case Hardening Process Quench in mm 1A 0.002-0.006 0.05-0.15 File Resistant Carbonitride Oil or Water 1B File Hard 2A 0.006-0.010 0.15-0.25 File Resistant Carbonitride Gas 2B Rockwell 89-93 HR15N or File Hard Oil or Water 3 0.010-0.020 0.25-0.50
13、Rockwell 89-93 HR15N Carbonitride or Carburize (Liquid or Gas) Oil or Water 3A File Resistant Gas (1) Where deemed feasible on particular parts and after consultation with the Materials Engineer, more than one Class should be specified. See “Appendix - General Information” for further discussion. (2
14、) 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 specific properties will have the requirements and methods of test detailed on the
15、 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 effective case depth method will be used for determination of case depth on the tempere
16、d 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 is specified, it is also necessary to specify the desired surface hardness. For ge
17、ars 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 Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo repro
18、duction or networking permitted without license from IHS-,-,-NUMBER: CEMS A-40A TITLE: Case Hardened Iron And Steel Parts CURRENT ISSUE DATE: October 2009 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppl
19、iers are required to assume all patent liability. 2009 by Navistar, Inc. OCTOBER 2009 Page 3 of 7 be desirable to specify file hardness. If a surface hardness range with a minimum less than Rockwell 55 HRC is specified, special effective case hardness must be designated on the drawing (see Section 1
20、0.0). 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 minimum specified on the drawing is required. Exceptions are noted below. (Note that ret
21、ention 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 suggested for edge retention.) TABLE II CLASSIFICATION(1) AND REQUIREMENTS (2) Heavy Cas
22、es Navistar Class(4) Effective Case Depth(3) Navistar Class(4) Effective Case Depth(3) inch mm 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 0.65-1.25 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.
23、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 should be specified. See “Appendix - General Information” for further discuss
24、ion. (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 will conform to the specified class; at the root fillet, it will be not les
25、s 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 conventional (total) case depth specified on the engineering drawing, the r
26、elationships 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 globular carbides are permitted. 6.4.2 Limited amounts of intergranular o
27、xides or associated transformation products are allowed, but to a depth no greater than 0.001 inch (25m). Where performance requires no intergranular oxides or associated transformation products, this should be specified on the part drawing. 6.4.3 While bainite in the case is not desired, a small am
28、ount 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 part. Case depth measurements on gear teeth will be made at two locations:
29、 (1) the pitch line, and (2) the root fillet, both Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS A-40A TITLE: Case Hardened Iron And Steel Parts CURRENT ISSUE DATE:
30、 October 2009 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. 2009 by Navistar, Inc. OCTOBER 2009 Page 4 of 7 on a plane midway between the ends of the t
31、ooth. 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 in the following figure. 7.0 QUALITY All product supplied shall be clean an
32、d 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 control limits established by the supplier for the product and that the process is capable of meeting
33、 all requirements of this specification. 8.0 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 perpendicular to the significant surface using a micrometer ocular calibrated to read in thousandths of
34、 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 unetched section perpendicular to the significant surface, using a properly calibrated microhard
35、ness 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 adjacent impressions or by the surface. Using loads of 500 or 1000 grams force, spacings of 0.
36、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 traverse has been completed, measure the length of each impression, determine the Knoop hardness nu
37、mber, 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 approximately connecting the points. Determine the depth at which the curve crosses the Rockwell 50 HRC har
38、dness level. This is effective case depth. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS A-40A TITLE: Case Hardened Iron And Steel Parts CURRENT ISSUE DATE: October
39、 2009 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. 2009 by Navistar, Inc. OCTOBER 2009 Page 5 of 7 TABLE III - HARDNESS CONVERSIONS KNOOP ROCKWELL C K
40、NOOP ROCKWELL C KNOOP ROCKWELL C 251 20 380 38 650 56 256 21 391 39 670 57 261 22 402 40 690 58 266 23 414 41 710 59 272 24 426 42 732 60 278 25 438 43 754 61 284 26 452 44 776 62 290 27 466 45 799 63 297 28 480 46 822 64 304 29 495 47 846 65 311 30 510 48 870 66 318 31 526 49 895 67 326 32 542 50 9
41、20 68 334 33 558 51 342 34 576 52 351 35 594 53 360 36 612 54 370 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 the discretion of the producer. However, it is the producers responsibility to estab
42、lish 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 herein to compensate for stock removed during grinding or other manufacturing processes
43、. 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, preferably in a vise. With one hand at each end of the file, place a sharp portion of the fla
44、t 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 tends to bite or cut only with difficulty, the surface is considered “file resistant.
45、” 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 sharp areas remain. For a more detailed description of the file test, see SAE J864. 8
46、.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 satisfactorily to compare the surface hardness of the part being tested with that of a kno
47、wn standard. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS A-40A TITLE: Case Hardened Iron And Steel Parts CURRENT ISSUE DATE: October 2009 This document is restric
48、ted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. OCTOBER 2009 Page 6 of 7 9.0 SOURCE APPROVAL AND QUALITY CONTROL 9.1 Supplier Requirements All suppliers to NAVISTAR are required to be registered to ISO 9
