1、 WORLDWIDE ENGINEERING STANDARDS General Specification GMW16845 Chilled Cast Iron Camshafts Copyright 2012 General Motors Company All Rights Reserved November 2012 Originating Department: North American Engineering Standards Page 1 of 9 1 Introduction Note: Nothing in this standard supercedes applic
2、able laws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Scope. For finish machined, ready-to-install chilled cast iron camshafts. 1.2 Mission/Theme. This specification defines the requirements and test condi
3、tions for finish machined chilled cast iron camshafts in three material types. 1.3 Classification. Not applicable. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 945 2.2 GM Standards/Specifications. GMW4 GMW
4、16331 GMW3059 3 Test Preparation and Evaluation 3.1 Resources. 3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. 3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variable
5、s as specified in this standard shall be determined correctly with respect to their physical definition. 3.1.3 Facilities. Conforming to the relevant test procedure. 3.1.4 Equipment. Conforming to the relevant test procedure. 3.1.5 Test Vehicle/Test Piece. Not applicable. 3.1.6 Test Time. Not applic
6、able. 3.1.7 Test Required Information. Not applicable. 3.1.8 Personnel/Skills. Not applicable. 3.2 Preparation. 3.2.1 Test Samples. Conforming to the relevant test procedure. 3.3 Conditions. Conforming to the relevant test procedure. 3.3.1 Environmental Conditions. Not applicable. 3.3.2 Test Conditi
7、ons. Deviations from the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 3.4 Instructions. Not applicable. 3.5 Data. Not applicable. 3.6 Safety. This standard may involve hazardous materials, oper
8、ations, and equipment. This standard does not propose to address all the safety problems associated with its use. It is the responsibility of the user of this Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitt
9、ed without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 2 of 9 standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 3.7 Do
10、cumentation. Samples of components or material released to this standard shall be tested for conformity with the requirements of this standard and approved by the responsible GM Department prior to the start of delivery of production level components or materials. Any change to the component or mate
11、rial, e.g., design, function, properties, manufacturing process and/or location of manufacture requires a new release of the product. It is the sole responsibility of the supplier to provide the customer, unsolicited, with documentation of any change or modification to the product/process, and to ap
12、ply for a new release. If not otherwise agreed to, the entire verification test shall be repeated and documented by the supplier prior to start of delivery of the modified or changed product. In some cases, a shorter test can be agreed to between the responsible GM department and the supplier. 3.7.1
13、 Test Results. The results of the tests shall be summarized in a test report. 3.7.2 Deviations from Test Procedure. Deviations from the requirements of the test procedures shall be agreed upon between the supplier and the purchaser. Such requirements shall be specified on component drawings, test ce
14、rtificates, reports etc. 4 Requirements and Procedure 4.1 Material. Type A: Unalloyed cast iron. Type B and C: Alloyed cast iron which forms a ledeburitic skin in the chilled area next to the casting mold. The composition selection results in a high degree of abrasion resistance by adding alloying e
15、lements such as chromium, nickel and molybdenum. 4.2 Chemical Composition. 4.2.1 Chemical Composition in % by Mass. See Table 1. Table 1: Chemical Composition Element Unit Type A Type B Type C GMW4M-IR-C-G250 modified Alloy 1 Alloy 2 Carbon % by mass 3.00 to 3.40 3.10 to 3.50 3.40 to 3.80 3.10 to 3.
16、60 Silicon % by mass 1.90 to 2.40 1.80 to 2.50 1.50 to 2.20 1.70 to 2.20 Manganese % by mass 0.60 to 0.90 0.50 to 0.80 0.60 to 0.90 0.60 to 1.10 Phosphorus % by mass 0.20 max. 0.20 max. 0.20 max. 0.20 max. Sulfur % by mass 0.12 max. 0.15 max. 0.05 max. 0.15 max. Chrome % by mass not defined 0.50 to
17、0.90 0.70 to 1.00 0.35 max. Molybdenum % by mass not defined 0.15 to 0.25 0.15 to 0.25 1.0 max. Nickel % by mass not defined 0.15 to 0.25 0.40 to 0.70 1.0 max. Copper % by mass not defined not defined not defined 0.50 max. Tin % by mass not defined not defined not defined 0.12 max. 4.2.2 If Alloy Ty
18、pe A is specified, Type B Alloy 1 or 2 may also be used. 4.2.3 If Alloy Type B is specified, Types 1 or 2 may be used interchangeably. 4.2.4 The microstructure of these materials is dependent on the chemical composition and the chilling speed of the castings. The chemical composition values listed i
19、n 4.2.1 are intended as guidelines and, unless otherwise 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 GMW16845 Copyright 2012 General Mot
20、ors Company All Rights Reserved November 2012 Page 3 of 9 agreed upon, are left to the discretion of the cast iron supplier. Hardness and microstructure are the primary requirements for this specification. Chemical composition is secondary. 4.3 Hardness on the Finish Ground Surface. All hardness mea
21、surements shall be taken on the equivalent finish ground surface. 4.3.1 Bearing journals and the front face, (200 to 285) HB 5/750. 4.3.2 Lobe Surface Hardness. Nose: HRC 48 minimum; Base Circle: HRC 40 minimum Because of the possibility of isolated pearlite spots on the cam lobe surface, sporadic h
22、ardness values may be below the specification limit. Appendix A defines the hardness readings for the nose and base circle of the lobes. See it for details on sample preparation and for referee hardness measurements criteria. 4.4 Microstructure of the Finish Lobe Surface. Microstructure shall be eva
23、luated at the equivalent finish machined surface. 4.4.1 Camshaft Lobe. 4.4.1.1 The depth of chill over the entire lobe contour shall be 5 mm minimum. 4.4.1.2 The microstructure in the chill zone shall consist of a ledeburitic skin of 1 mm. Total sided graphite and pearlite separations are not permis
24、sible. Concentrated pearlite separations are allowed in the following areas per Figure 1, for Area “A” and “B” a 5% maximum pearlite separation is allowed. For Area “C” a maximum pearlite separation of 10% is allowed. 4.4.1.3 The macrostructure in the chilled zone shall consist of the following: 50/
25、50 (“light-dark” border) = 50% surface proportion Ledeburite (light = “white”) + 50% surface proportion Pearlite level (dark = “grey”). 4.4.2 Bearings and Core Zone. Gray cast iron. The evaluation shall be done with the rating charts for cast iron according to ISO 945. 4.4.2.1 Chilling is possible a
26、nd acceptable in the transition zone of the cam bearing to the cam lobe. In the core zone carbide separations are permissible, however they are not permissible in the areas of machining (e.g., tapped hole). 4.4.2.2 Graphite Formation. Graphite form I (fine lamellar) per ISO 945 Figure 1. Graphite di
27、stribution of Type A, B, D and E per ISO 945 Figure 2. Graphite size of 5 to 8 with isolated areas of size 4 per ISO 945 Figure 3. 4.4.2.3 Pearlite Formation. Uniform, predominantly dense lamellar Pearlite, no Ledeburite. 4.4.2.4 Ferrite Proportion. Free ferrite only in isolated instances. 4.5 Gener
28、al Characteristics. The camshafts shall be free of fissures, macroporosity (bubbles), gas bubbles, slag, impurity inclusions, and machining defects such as breakout, damage from grinding the flash, grinding burns, etc. 4.6 Surface Finish. Bearings and lobes are ground and microfinished. In addition,
29、 bearings are lapped to the peak-to-valley height specified in the corresponding drawing. 4.6.1 Surface Quality. On cam lobes the following deviations regarding the surface quality are possible. 4.6.1.1 Cam Lobe. See Figure 1 and Table 2. Copyright General Motors Company Provided by IHS under licens
30、e with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 4 of 9 RSA = Running Surface Area Figure 1: Cam Lobe Table 2: Surfa
31、ce Quality Cam Lobe Pore Dimension Number of Pores Area A Area B Area C and area within 0.3 mm from side of lobe Diameter: 0.3 mm No surface defects accepted 6 max., 3 max. within 3.0 mm diameter, 10.0 mm minimum from nearest surface defects 10 max., 5 max. within 4.0 mm diameter, 10.0 mm minimum fr
32、om nearest surface defects Diameter: 0.5 mm 2 max. 10.0 mm minimum from each other Diameter: 0.8 mm 2 max. 10.0 mm minimum from each other Total length of surface defects (parallel to center line camshafts) 0.8 mm max. Chips (broken edges) Not accepted Lobes with chamfer: Accepted outside the runnin
33、g surface and outside the distance of 0.3 mm to the edge of the running surface area Lobes without chamfer: Accepted 0.5 mm max. of the edge of running surface. Contact area shall not be affected. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for Resal
34、eNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 5 of 9 4.6.1.2 Bearing and other Surfaces. See Figure 2 and Table 3. Figure 2: Bearing and Other Surfaces Tab
35、le 3: Surface Quality Bearing and other Surfaces Pore Dimension Number of Pores Area D Area E Area F Area G Diameter: 0.3 mm 6 max.; 3 max. within 3.0 mm diameter, 10.0 mm minimum from nearest surface defect 2 max.; 10.0 mm minimum from each other Diameter: 2,0 mm 2 max.; 10.0 mm minimum from each o
36、ther Diameter 2.0 mm with a depth of 0.5 mm max. 2 max.; 1x per surface, not in radius area 2 mm x 4 mm with a depth of 0.5 mm max. 2 max.; 1x per surface Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted w
37、ithout license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 6 of 9 4.7 Hollow-cast Shafts. Hollow-cast shaft bores shall be free of cast residues and impurities of all kinds. 4.7.1 Hollow cast shafts that come i
38、n contact with engine oil shall be either be cast with glass core rods or shall be completely machined. 4.8 Identification Marks. 4.8.1 The GM logo to GMW16331 and the manufacturers logo for unmachined parts shall be engraved at suitable locations (see drawing) where feasible. 4.8.2 The code letter,
39、 if required, the supply number, and the date of manufacturer to GMW16331 shall be engraved. 5 Provisions for Shipping Not applicable. 6 Notes 6.1 Glossary. Not applicable. 6.2 Acronyms, Abbreviations, and Symbols. GSSLT Global Subsystem Leadership Team RSA Running Surface Area 7 Additional Paragrap
40、hs 7.1 All parts or systems supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: GMW16845 9 Release and Revisions This standard was ori
41、ginated in July 2012. It was first approved by the Non-ferrous Metals and Castings 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 Ge
42、neral Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 7 of 9 Appendix A: Flow Chart for Hardness Measurements Note: The nose and t
43、he base circle criteria must be acceptable for the camshaft to be acceptable. Figure A1: Lobe Nose Hardness Testing Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWID
44、E ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 8 of 9 Figure A2: Base Circle Testing Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without
45、license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16845 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 9 of 9 Figure A3: Tip Cutting and Grinding Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
