1、_SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.Copyright 2012 SAE InternationalAll rights reserved. No part of this publication may b
3、e reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada)Tel: +1 724-776-4970 (outside USA)Fax
4、: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AMS2588AEROSPACEMATERIALSPECIFICATIONAMS2588Issued 2012-10Ultrasonically Activated Needle Peen FormingRAT
5、IONALEThis new specification establishes equipment and process requirements for forming or straightening metal parts using Ultrasonically Activated Needle Peening.1. SCOPE1.1 PurposeThis specification covers the equipment and process requirements for forming or straightening metal parts using Ultras
6、onically Activated Needle Peening.1.1.1 Process DescriptionUltrasonic kinetic energy is transferred from a vibrating metallic element to the peen forming media (needles) contained in an end piece. See Figures 4 and 3 respectively. The equipment can be used manually by an operator or automatically in
7、 connection with a CNC machine, e.g., an industrial robot. The equipment set (Figure 1) is composed of a central control unit and a machine held tool, the peening head (Figure 2).1.2 ApplicationsUltrasonically activated needle peening is typically used to form and straighten metallic parts by induci
8、ng compressive residual stresses on selected surfaces in order to produce the desired part curvature. The process is successfully applied to part geometries for which the depth of introduced residual stresses is significant in comparison to part thickness at that location.2. APPLICABLE DOCUMENTSThe
9、issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the reference document has been cancelled a
10、nd no superseding document has been specified, the last published issue of that document shall apply.2.1 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959,Tel: 610-832-9585, www.astm.org.ASTM E 18 Rockwell Hardness of Metallic
11、MaterialsASTM A 751 Standard Test Methods, Practices, and Terminology for Chemical Analysis of Steel ProductsSAE AMS2588 Page 2 of 142.2 AISI PublicationsAvailable from American Iron and Steel Institute , 1140 Connecticut Avenue, NW, Suite 705, Washington, DC 20036,Tel: 202-452-7100, www.steel.org.A
12、NSI/ASME B46.1 Surface Texture, Surface Roughness, Waviness and Lay2.3 Definitions2.3.1 Peening exposure time is determined by the time required to obtain the required curvature of the part.2.3.2 Over-formed parts areas are more difficult to correct than unpeened or under-peened areas.2.3.2.1 As eac
13、h part may react differently, over-forming may occur and may be corrected by peening the opposite surface unless prohibited by drawing callout.2.3.3 COVERAGEThe required curvature may not result merely from a fully covered surface. The part is processed to obtain a curvature and not a defined covera
14、ge. Coverage greater than 100% may not produce a significant increase of curvature.2.3.4 COGNIZANTThe term applied to the engineering organization responsible for the design of the parts, its allied quality assurance organization, or a designee of these organizations.2.3.5 END PIECEFixture encapsula
15、ting and guiding the needles. The end piece suitably locates and orientates needles on the sonotrode vibrating surface.2.3.6 MEDIA BATCHThe particular material, hardness, size and amount of media (needles) that are used for a single setup.2.3.7 MEDIA BATCH CHANGE POINTThe media (needles) batch renew
16、al criteria when any of the related characteristics are out of requirements.2.3.8 MEDIA CLUSTERAll the needles included on the End piece2.3.9 SONOTRODE VIBRATION AMPLITUDEVibration amplitude is the axial displacement of the sonotrode top surface that throws the media. The amplitude is characterized
17、by the difference between the peak and valley of the sine wave displacement. 2.3.10 SOURCEThe organization from which the manufactured needles are purchased and which provides the statement of conformity (4.3.6).2.3.11 CNC MACHINEA machine tool that uses programs to precisely and automatically displ
18、ace the peening head above the peened part locations (e.g. robot, multiple axis CNC milling machine).SAE AMS2588 Page 3 of 143. TECHNICAL REQUIREMENTS3.1 Equipment3.1.1 Central Control Unit and Peening Head:FIGURE 1: EQUIPMENT SET DESCRIPTIONThe ultrasonically activated needle peening equipment shal
19、l provide a means of transferring kinetic energy to the needle contained in an end piece using a metallic element vibrating at an ultrasonic frequency. The equipment set (Figure 1) shall consist of a central unit and a hand held tool, the peening head.3.1.1.1 Peening HeadFIGURE 2: PEENING HEAD COMPO
20、NENTSThe peening head (Figure 2) shall consist of a piezo-electric exciter and a sonotrode (Horn) and, in some cases, a booster used to amplify the vibration.3.1.1.2 Sonotrode (Horn)The sonotrode is the metallic element vibrating at an ultrasonic frequency that transfers kinetic energy to the needle
21、s. Peening HeadEnd PieceCentral UnitSonotrode/HornExciterEnd PieceSAE AMS2588 Page 4 of 143.1.2 End piece:FIGURE 3: END-PIECE EXAMPLEThe end piece (Figure 3) is the component that contains and guides the needles (Figure 4). End pieces can be part-specific and location-specific as required to achieve
22、 the requirements, although each end piece may be used for other parts depending upon geometry. See 4.6.3.3.1.2.1 Each end piece shall be referenced and serialized. The end piece(s) selected shall be suitable for the area(s) of the part being peened. The end piece material shall be chosen to limit t
23、he part abrasion and the localized heat that occurs during the needle peening process.3.1.3 Needle Technical Requirements3.1.3.1 For metal parts, the needles shall conform to the requirements of Table 1 unless otherwise approved by the cognizant engineering organization. See 4.6.3.3.1.3.2 Needles sh
24、all conform to the following requirements:FIGURE 4: NEEDLE GEOMETRYSAE AMS2588 Page 5 of 14TABLE 1: DIMENSIONS AND HARDNESS OF STEEL NEEDLESReference a b c d Hardness2/1.2 R0.75 0.030(0.75) 0.047(1.2) 0.079(2) 0.047(1.2) 60-66 HRC3/2 R5.35 0.211(5.35) 0.079(2) 0.118(3) 0.079(2) 60-66 HRC4/3 R8 0.315
25、(8) 0.118(3) 0.157(4) 0.118(3) 60-66 HRC5/4 R16 0.630(16) 0.157(4) 0.197(5) 0.157(4) 60-66 HRCNotes:Dimension units are inch (mm)a is front impact end radiusb is front impact end diameterc is guiding diameterd is rear thrown end diameter3.1.3.3 The impact surface of the needles shall be free of scra
26、tches and cracks. They shall be inspected at 10 to 20X magnification daily and replaced if small impact cracks are found which can result in material removal and create potentially damaging sharp edges.3.1.3.4 ProtectionNeedles shall be visibly free of grease and oil before being loaded into the end
27、 piece.3.1.4 Peening Head Parameter Monitoring:The equipment shall be equipped with computerized devices for continuously monitoring the part-number-specific parameters shown in Table 2 within the usual tolerances indicated.TABLE 2: TOLERANCES FOR ULTRASONICALLY ACTIVATED NEEDLE PEENING HEADParamete
28、r Units Process TolerancePlus or MinusAmplitude Inches (millimeters) 0.00024 (0.006)Frequency Hz 400The amplitude of sonotrode vibration shall be recorded at the beginning of the operation and each time it is set to another value. The amplitude shall be recorded every 4 hours maximum of continuous u
29、se and each time the treatment is interrupted for more than one hour, unless another schedule is approved by the cognizant engineering organizationThe amplitude shall be measured using a mechanical, electronic or optical gage accurate to 0.00004 inch (0.001 mm)displacement.3.1.5 The equipment shall
30、be capable of maintaining the amplitude within the Table 2 tolerances and capable of aborting peening within one second after a detected tolerance for frequency in Table 2 is exceeded. The peening equipment shall retain in memory any abort details for the parameters listed in Table 2 and be capable
31、ofresuming operation to complete the balance of the peening operation from the position of shut down after the out-of-tolerance condition has been corrected. Parts processed during an aborted cycle shall be reported by the processor.3.1.6 For automatic operation, needle peening device displacements
32、shall be also monitored. The peening shall be interrupted when Table 3 limits are exceeded.SAE AMS2588 Page 6 of 14TABLE 3: PARAMETERS FOR ULTRASONICALLY ACTIVATED NEEDLE PEENING AUTOMATIC EQUIPMENTParameter Units Process TolerancePlus or MinusPart Translation % Inch/min (% mm/min) 2Part Rotation %
33、Revolution/min. 23.2 Needle Peening Intensity Determination3.2.1 Customized intensity test specimen size, shape, material, hardness, preset time, and surface finish shall be approved by the cognizant engineering organization. See 8.3. Calibrated gages or measurement equipment shall be used to measur
34、e the arc height at the opposite side of the peened side within 0.002 inch (0.05 mm).3.2.2 Inspection3.2.2.1 Purchaser requirements shall be observed and applied to the production parts.3.2.2.2 All parts shall be visually clean prior to needle peening. When purchaser does not supply clean parts to t
35、he processor, parts shall be cleaned in accordance with a procedure supplied or approved by purchaser.Halogenated solvents shall not be used to clean titanium alloy parts. Parts shall be visually inspected to verify freedom from grease, dirt, oil, corrosion, burrs, sharp edges, mechanical damage and
36、 corrosion-preventive coatings such as anodic coatings, plating, or paint. Use of magnification up to 10X as a referee for part inspection is permitted.3.2.3 MaskingAreas of the part that are designated to be free from any peening shall be suitably masked or protected from the peening media or subse
37、quent damage. Internal threads shall be protected to prevent damage to the starting threads.3.3 Equipment Preparation3.3.1 The peening head, the end piece with associated needles and process parameters shall be suitably established to comply with the part needle peening requirements.Needles front im
38、pact end shall be inspected and replaced as required by processor in accordance with 3.1.3.3.3.4 Procedure3.4.1 The part shall be held stationary during the needle peen forming operation. The part may be directly peened on the curvature gage.3.4.2 Initially, to limit part needle peening, formed part
39、s shall be carefully inspected to identify areas requiring straightening, correction or forming to the required curvature. A sliding gage (Figure 5) or other gages may be used to verify curvature requirement.FIGURE 5: SLIDING GAGESAE AMS2588 Page 7 of 143.4.3 The needle peening exposure shall be mon
40、itored and adjusted by the operator to obtain the required curvature. The curvature development shall be continuously inspected by the operator to avoid over-forming. 3.4.4 Intensity: Needle peening intensity shall be specified or approved by the cognizant engineering organization.3.4.5 Stationary u
41、ltrasonic needle peening longer than two seconds is prohibited. The Peening head shall always be in motion to avoid over peening of a specific area. It shall be moved circularly along its main trajectory displacement as shown in Figure 6.FIGURE 6: NEEDLE PEENING HEAD TRAJECTORIES3.4.6 Needle peening
42、 on part edges and radii may be limited and shall be approved by the cognizant engineering organization.3.4.7 Areas designated not to be peened shall be identified by the cognizant engineering organization and protected.3.4.8 Production peening setups shall use the computer pre-program and the proce
43、dure sheet to designate the machine and all settings.3.4.9 Part Holding FixtureHolding fixture is not mandatory. If the part is held in a fixture designed to rotate and/or translate the part on its axis, thefixture shall be numbered and recorded on the peening procedure sheet. See 4.6.3.3.5 Post-Pee
44、ning Treatment3.5.1 A visual inspection shall be performed on all needle-peened part surfaces to detect any surface damage (notches, scratches and rollover of edges). A 10x magnifier can be helpful but not compulsory. If any damages are observed, part surface shall be corrected in accordance with pr
45、ocedures approved by the cognizant engineering organization. Otherwise, the part shall be rejected.3.5.2 All protective masks shall be removed from surfaces of parts by a method that will not erode or scratch surfaces.3.5.3 Dimensions and surface roughness shall conform to specified requirements. To
46、 reclaim specified surface roughness, honing, lapping, or polishing may be performed so long as required curvature is maintained.3.5.4 Subsequent thermal processing shall be performed only when approved by the cognizant engineering organization. In order to minimize reduction of the residual stresse
47、s imposed by peen forming, the temperature of the peened parts shall not exceed the maximum limits of Table 4. Main TrajectoryCircular MotionSAE AMS2588 Page 8 of 14TABLE 4: MAXIMUM TEMPERATURE LIMITS FOR PEENED FORMED PARTS WHILE IN THE PEENING FACILITYAlloy TemperatureSteels, other than corrosion
48、resistant1475 qF (246 qC)Corrosion-Resistant Steels2750 qF (399 qC)Aluminum Alloys 205 qF (96 qC)Titanium Alloys 475 qF (246 qC)Magnesium Alloys 200 qF (93 qC)Nickel and Cobalt Alloys 1000 qF (538 qC)1 Except 300 F (149 qC) for steel parts that are tempered below the recommended 475 F (246 qC) maxim
49、um after a quench hardening operation.2 Except 475 F (246 qC) for PH and cold worked 300 series CRES (aka, stainless steel).3.5.5 Peen formed parts shall be cleaned and decontaminated with a suitable method.3.5.6 Parts subject to corrosion shall be protected during processing and until protective coating or packaging is completed. The method of protection shall be approved by the cognizant engineering organization.4.
