NAVISTAR CEMS A-39-2001 Shot Peening of Metal Parts (Includes Appendix).pdf

1、INTERNATIONAL TRUCK AND ENGINE CORPORATION CEMS (CORPORATE ENGINEERING MATERIAL SPECIFICATION) TITLE: Shot Peening Of Metal Parts NUMBER: CEMS A-39 CURRENT ISSUE DATE: April 2001 1.0 SCOPE This specification covers the Companys requirements for shot peening metal parts. 2.0 INTRODUCTION Shot peening

2、 produces a compressively stressed layer on the surface, which improves the fatigue life of a part by reducing the effect of an applied tensile stress. 3.0 CONTENTS REFERENCE DOCUMENTS CLASSIFICATION OR GRADE DESIGNATION GENERAL REQUIREMENTS QUALITY METHODS OF TEST SOURCE APPROVAL AND QUALITY CONTRO

3、L DESIGNATION ON DRAWINGS AND PURCHASE ORDERS PACKING AND SHIPPING APPENDIX PAGE 1 1 1 3 3 4 4 4 Green Sheets 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 s

4、pecification. Quality System Standard QS-9000 (IS0 9001) INTERNATIONAL IQR Quality Standard INTERNATIONAL Manufacturing Standard D- 13 CFR Title 29, Part 1910 SAE J 442 SAE J 441 SAE J 827 SAE J 443 5.0 CLASSIFICATION Shot peening is classified by the intensity of the shot application as measured by

5、 strip. 6.0 GENERAL REQUIREMENTS Parts supplied to this specification will meet the following requirements. SAE J444 the height of the Almen This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical St

6、andards. 02001 International Truck and Engine Corporation. Suppliers are required to assume all patent liability. APRIL, 2001 Page 1 of 4 NUMBER: CEMS A-39 6.1 Intensitv The intensity designation will include a number and a letter. The letter will specify which Almen test strip (A, C or N) is to be

7、used and the number will indicate the minimum arc height that the treatment will produce on the specified strip. The arc height is measured in 0.025 mm units. Piece part coverage will be 100% minimum unless otherwise specified. An “H suffix on the intensity designation will indicate special hard sho

8、t must be used. TITLE CURRENT ISSUE DATE: Shot Peening Of Metal Parts April 2001 Test Strip Arc Height Intensity Designation Shot Size* Units Class * The shot diameter will be no greater than 50% of the radius of any fillet or 25% of any aperture to be peened. See “Appendix - General Information” fo

9、r discussion. 6.1.1 All areas where specified intensity must be achieved as well as any areas that cannot tolerate peening will be identified on the drawing. 6.2 Intensitv Control Test strips, holders and gages will conform to the requirements published in SAE 5442. 6.2.1 Two strips must be used for

10、 each determination. The minimum test frequency to insure the specified intensity is at the beginning and end of each Set-up and at last every eight hours. When a test strip does not meet the requirements all parts processed since the last satisfactory test are rejected. 6.2.2 When requested , the s

11、upplier will provide the purchaser with test strips and with certification that all parts meet the specified requirements. 6.3 Shot Control The shot used to process parts to this specification will conform to the requirements published in SAE 5441 or SAE 5827 and 5444, unless otherwise specified. Se

12、e “Appendix - General Information.”. The shot will be at least as hard as the parts being peened except when the intensity designation has an “H suffix then at least 90% of the hardness values for the shot used will be RC 58 to 65. 6.3.1 The shot will be essentially free from cracks, porosity, sharp

13、 edges and broken pieces. Cut wire, if used, must be conditioned to eliminate sharp edges. Cast Cut Steel Wire 6.4 Shot Peening; Equipment The machine used for shot peening will provide a mechanical means for moving the work through the shot stream in either translation or rotation or both to insure

14、 reproducing consistently, in all specified areas, the shot peeing intensities required. It will also include a separator for the continuous removal of broken or defective shot during operation. SA 12A 14A 16A 6C 8C IND This document is restricted and may not be sent outside International Truck and

15、Engine Corporation or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 02001 International Truck and Engine Corporation. Sto 12 S110 - 12tO 16 S170 - 14to 18 S230 CW23 16to20 S330 CW35 6to8 S460 CW47 8 to 12 S660 As Indicated on

16、 Drawing APRIL, 2001 Page 2 of 4 NUMBER: CEMS A-39 6.5 Prepeening; Process All forming, machining, grinding, heat treating, burr removal and other processing in the area to be peened will be completed prior to shot peening except as indicated below. Unless otherwise specified, all testing such as ma

17、gnetic particle, dye penetrant, hardness, etc., will be completed prior to shot peening. 6.5.1 All areas that require protection from the shot peening treatment will be indicated on the drawing. Materials used for masking will be easily removed by nonabrasive methods. Masking must protect designated

18、 areas to within k 3 mm of designated boundary unless otherwise specified. TITLE CURRENT ISSUE DATE: Shot Peening Of Metal Parts April 2001 6.6 Post Peening; Treatments All shot, shot residue and masking will be removed by nonabrasive methods only. 6.6.1 Straightening after shot peening is prohibite

19、d, unless approved by the controlling design engineering department. 6.6.2 Surface finish adjustment of the specified peened area by polishing, lapping and honing, will be limited to material removal of not more than 10% of the “A” intensity arc height if part hardness is less than RC 45; or 5% of t

20、he “A” intensity arc height for parts RC 45 and greater. Convert “N or “C” intensities to equivalent “A” value. 6.6.3 Unless otherwise specified, heating after shot peening such as to bake or cure paint will be limited to: 230C (450F) max for steel; 135C (275F) max for aluminum. 6.6.4 Treated surfac

21、es will be suitably cleaned and protected with a rust inhibiting coating before shipping or storage. 7.0 OUALITY All product supplied shall be clean and free from dirt, oils, or defects harmful to product performance. The supplier should be capable of providing statistical evidence that parts have b

22、een processed with process control limits established by the supplier for this product and that the process is capable of meeting all requirements of this specification. 8.0 METHODS OF TEST 8.1 Test Strip Intensitv Support the appropriate tests strips so that their exposure simulates that of each sp

23、ecified area. Follow the procedure outlined in SAE 5443 to generate an “Intensity Determination Curve.” Saturation of the test strip is defined as the “Shortest time” point on the curve from which doubling that time will result in no more than a 10% increase in arc height. Full or 100% coverage of t

24、he test strip or complete denting of the surface will correspond very closely to saturation. Use a fresh test strip for each exposure; no strip may be reused. 8.2 Piece Part Intensitv All variables, except time, determined above must be maintained. The time to get saturation or 100% coverage of the

25、piece part will vary with the base hardness. This time will be determined visually. A 150% of 1.5 coverage specification refers to 1-1/2 times the piece part saturation time. This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without perm

26、ission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 02001 International Truck and Engine Corporation. APRIL, 2001 Page 3 of 4 NUMBER: CEMS A-39 8.3 Coverage Piece part coverage will be determined visually using a 10 power magnifying glass. Full or 100% c

27、overage will be uniform with complete denting or obliteration of the original surface. TITLE CURRENT ISSUE DATE: Shot Peening Of Metal Parts April 2001 9.0 SOURCE APPROVAL AND OUALITY CONTROL 9.1 Supplier Requirements Suppliers must conform to the requirements of the International IQR Quality Standa

28、rd which includes conformance to the QS-9000 (IS0 9001) Quality System Standard. A mutually acceptable Quality Control Plan as described therein is required for source approval to the requirements of this specification. 9.2 Approval Parts supplied against contracts or purchase orders citing this spe

29、cification shall be equivalent in all respects 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 pro

30、duct are required, the supplier shall notify Materials Engineering at TDTC and International Purchasing and Suppliers 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 Sh

31、eet(s) (MSDS), in accordance with CFR Title 29, Part 1910 shall be submitted with the request for change. 9.3 Process Control The supplier shall either perform and report results of tests on specific lots of parts produced or provide statistical evidence of the lot having been produced in a state of

32、 statistical control and with a process capable of providing all required properties. The part supplier and the plant metallurgist andor the quality control manager of the using International plant may determine testing and reporting requirements on specific products. 10.0 DESIGNATION ON DRAWINGS AN

33、D PURCHASE ORDERS The class, suffixes and other required information will be specified as follows: Examples: Shot Peen, Class SCH, Coverage 150% min, CEMS A-39 Shot Peen, Class 12A, CEMS A-39 Shot Peen, Class IND, 12-20 AH, CEMS A-39 Shot Peen, Class IND, lOC, min, CEMS A-39 11.0 PACKING AND SHIPPIN

34、G Packing and shipping will be in accordance with Navistar Manufacturing Standard D-13. This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent

35、liability. 02001 International Truck and Engine Corporation. APRIL, 2001 Page 4 of 4 INTERNATIONAL TRUCK AND ENGINE CORPORATION NUMBER: CEMS (CORPORATE ENGINEERING MATERIAL SPECIFICATION) CEMS A-39, APPX TITLE: CURRENT ISSUE DATE: Shot Peening Of Metal Parts April 2001 Materials Engineering Material

36、s Engineering July 1999 WRiTTENREVIE WED BY: PPROVED BY: SUPERSEDES ISSUE OF: APPENDIX GENERAL INFORMATION - Not a Requirement For comparison of most grades of structural tubing with other types of steel tubular products, see Table III in “Appendix - General information,“ CEMS A- 10, Part I. CONTENT

37、S INTRODUCTION EQUIPMENT SHOT INTENSITY SHOT SIZE VERSUS INTENSITY MATERIAL, THICKNESS AND INTENSITY MASKING SURFACE FINISH APPLICATIONS PAGE 1 1 2 2 3 3 5 5 5 A.l INTRODUCTION Shot peening is the process of exposing a metal surface to bombardment by a high velocity stream of solid particles. This t

38、reatment creates a compressively stressed layer on that surface which will reduce the effect of a tensile stress from an applied load and thereby increase the load carrying capacity in fatigue. Fatigue strength, for high cycle applications, can be improved significantly. Depending on the application

39、, this can vary from 20% to well over 100%. The percent improvement decreases as higher overloads are reached. Resistance to stress corrosion cracking can also be increased. A.2 EQUIPMENT The acceleration of the particles is usually accomplished in one of two ways, centrifugal force or air pressure.

40、 The centrifugal force method employs a rotating wheel and the shot velocity is determined by the peripheral speed of that wheel. Usually, the wheel diameter and speed are controlled to produce a shot velocity about equal to that delivered by a direct pressure gun operating at 80 psi. The volume of

41、shot delivered is quite high, but since the stream tends to diverge, a portion of it never reaches the part. This document is restricted and may not be sent outside International Truck and Engine Corporation or reproduced without permission from Corporate Technical Standards. Suppliers are required

42、to assume all patent liability. 02001 International Truck and Engine Corporation. APRIL, 2001 Page 1 of 6 NUMBER: TITLE CURRENT ISSUE DATE: CEMS A-39, APPX Shot Peening of Metal Parts April 2001 A.2 (Continued) The power consumed is only a fraction of that required for a compressor to drive a direct

43、 pressure gun. Air pressure guns employ either induction or gravity to feed shot into the air stream. The induction gun uses an air jet to introduce the shot into the stream; mixing occurs at the nozzle. The shot volume is about the same as a direct pressure gun of same size as the air jet, but the

44、velocity is reduced due to the energy consumed to create the vacuum used for shot induction. The direct pressure gun is supplied with shot fed by gravity from a pressurized reservoir. A single line delivers both shot and the propelling air to the nozzle. Shot velocity is proportional to air pressure

45、. A.3 SHOT The shot used for peening must be essentially free from sharp edges or corners, as they can damage the surface by creating stress risers which may detract from the available improvement and actually abrade the surface. To reduce the chances of this occurring, the shot should be conditione

46、d to removed edges and promote the breakdown of cracked or defective shot. The fragments can then be removed prior to use. For cut wire, conditioning is essential. Some specifications list the degree and extent of cracked or porous shot allowable, as well as shape requirements. This is mainly for ma

47、nufacturing control. It may be advantageous to order preconditioned shot which is more expensive, but better since shot breakdown during the peening operation and, therefore, replacement costs are reduced. A.4 INTENSITY When discussing intensity only saturation intensity or the intensity produced wh

48、en there is 100% coverage and complete overlapping of dimples on the surface is considered. “Intensity” at any other point on the curve should be referred to as “arc height.” Shot peening intensity is indicated by the amount of curvature that is produced in a steel test strip by exposure to the stre

49、am. The curvature is measured in 0.025 mm units on a dial indicator. When necessary, a dial indicator with 0.001 inch (0.0254 mm) graduations may be used. A.4.1 There are three standard (Almen) test strips of different thickness currently in common use. This permits specifications, measurement and control in three intensity ranges, light (N), average (A) and heavy (C). The “A” strip is usually used as a general purpose range. To extend the range in either direction, the “N strip (reading about three times “A” heights) and the “C” strip (readings about 0.3 times “A” heights) are ava