1、Designation: A914/A914M 92 (Reapproved 2011)A914/A914M 16Standard Specification forSteel Bars Subject to Restricted End-Quench HardenabilityRequirements1This standard is issued under the fixed designation A914/A914M; the number immediately following the designation indicates the yearof original adop
2、tion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This specification covers hot-worked alloy and carbon-boron steel
3、s designed to attain restricted depth of hardening in theend-quench test. These steel compositions are identified by the suffix letter “RH” added to the conventional grade number.1.2 In general, steels with restricted hardenability (RH steels) will exhibit a hardness range not greater than 5 HRC at
4、the initialposition on the end-quench hardenability bar and not greater than 65 % of the hardness range for standard H-band steels(Specification A304) in the inflection region. Generally the restricted hardenability band follows the middle of the correspondingstandard H-band. An example of the RH ba
5、nd compared with the H band is given for Grade 4140 in Fig. 1.1.2.1 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combi
6、ning values from thetwo systems may result in non-conformance with the standard.1.3 This specification is expressed in both inch-pound units and SI units. However, the material will be supplied to inch-poundunits unless the purchase order specifies the “M” specification designation.2. Referenced Doc
7、uments2.1 ASTM Standards:2A29/A29M Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-WroughtA255 Test Methods for Determining Hardenability of SteelA304 Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability RequirementsE112 Test Methods for Dete
8、rmining Average Grain Size2.2 SAE Standards:3J 406 Methods of Determining Hardenability of SteelsJ 1268 Hardenability Bands for Carbon and Alloy H SteelsJ 1868 Restricted Hardenability Bands for Selected Alloy Steels3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 hardenability
9、the relative ability of a steel to harden under heat treatment becomes apparent in the degree to which thematerial hardens when quenched at different cooling rates.3.1.1.1 DiscussionHardenability is measured quantitatively, usually by noting the extent or depth of hardening of a standard size and sh
10、ape testspecimen in a standardized quench. In the end-quench test the depth of hardening is the distance along the specimen from thequenched end to a given hardness.1 This specification is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct respo
11、nsibility of Subcommittee A01.15on Bars.Current edition approved April 1, 2011Dec. 1, 2016. Published June 2011December 2016. Originally approved in 1992. Last previous edition approved in 20052011 asA914/A914M - 92(2005).(2011). DOI: 10.1520/A0914_A0914M-92R11.10.1520/A0914_A0914M-16.2 For referenc
12、edASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,
13、 PA 15096-0001,15096, http:/www.sae.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM
14、 recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO B
15、ox C700, West Conshohocken, PA 19428-2959. United States14. Ordering Information4.1 Orders for material under this specification should include the following information, in proper sequence:4.1.1 Quantity (weight),4.1.2 Name of material (alloy or carbon-boron steel),4.1.3 Cross-sectional shape,4.1.4
16、 Size,4.1.5 Length,4.1.6 Grade,4.1.7 End-quenched hardenability (see Section 9),4.1.8 Report of heat analysis, if desired (see Section 7),4.1.9 Special straightness, if required,4.1.10 ASTM designation and date of issue, and4.1.11 End use or special requirements.NOTE 1A typical ordering description
17、is as follows: 10 000 lb, alloy bars, round, 4.0-in. diameter by 10 ft, Grade 4140RH, heat analysis required,complete hardenability data required, ASTM AXXX, AXXXM dated _ worm gear.4.2 The purchaser shall specify the desired grade, including the suffix letters “RH”,“RH,” in accordance with Table 1.
18、4.3 Band limits are shown graphically and as tabulations in Figs. 2-23, inclusive. For specification purposes, one must usetabulated values of Rockwell hardness (HRC) as a function of distance from the quenched end of the hardenability bar, either ininch-pound units (sixteenths of an inch) or in SI
19、units (millimetres). Values below 20 HRC are not specified because such valuesare not accurate.4.3.1 Band limits shown graphically are so depicted for convenience in estimating the hardness values at various intermediatelocations on the end quench test bar for quick comparisons of the various RH gra
20、des. The values of “Approximate Diameter ofRounds with Same As-Quenched Hardness” shown above each RH-band, were selected from ranges appearing in Fig. 7 of SAEJ 406. The RH-bands are presented graphically, with distances from the quenched end in both inch-pound units and also SI units.4.4 For speci
21、fication purposes, RH-band steels shall exhibit hardness within the minimum and maximum HRC range specifiedat the J1 (J1.5-mm) position and shall meet one additional minimum and one additional maximum value. In this specification, thetwo additional hardness values shall represent the approximate har
22、dness for 50 % martensite for the minimum and maximumspecified carbon content, respectively (except where hardenability is too high; then the two additional hardness control values shallbe five HRC points below the maximum hardness value specified at the J1 (J1.5-mm) position).4.4.1 In general, thes
23、e points define the critical locations of the Jominy hardenability band for purposes of characterizing heattreatment response. The four specification points are circled in the tables of hardness versus Jominy distance and on the RH-bands.For all other Jominy positions, a tolerance of two points HRC
24、is permitted for a maximum consecutive 316-in. or 5-mm Jominydistance on the restricted hardenability band.4.4.2 For example, referring to Fig. 9, a hardenability test bar of a steel meeting the requirements for 4140RH must exhibit ahardness at J1 not less than 54 HRC, nor more than 59 HRC. At J12,
25、the test bar must exhibit hardness not less than 43 HRC, butthe maximum hardness can be as high as 52 HRC (or even 54 HRC if the region of the test bar is chosen as the exception). AtJ20, the bar must exhibit hardness not greater than 47 HRC, but the minimum hardness can be as low as 37 HRC (or as l
26、ow as35 HRC if this region of the test bar is chosen as the exception).4.4.3 A similar example, referring to Fig. 9, for 4140RH with distances from the quenched end in millimetres would limithardness at J1.5 mm to not less than 54 HRC nor more than 59 HRC. At J20 mm, the test bar must exhibit hardne
27、ss not less than42 HRC. At J30 mm, the test bar must exhibit hardness not greater than 48 HRC.5. Manufacture5.1 Melting PracticeThe steel shall be made by one or more of the following primary processes: open-hearth, basic-oxygen,basic-oxygen or electric furnace. The primary melting may incorporate s
28、eparate degassing or ladle refining and may be followedby secondary melting using electroslag remelting or vacuum arc remelting. Where secondary melting is employed, the heat shallbe defined as all the ingots remelted from a single primary heat.5.2 Slow CoolingImmediately after hot working, the bars
29、 shall be allowed to cool when necessary to a temperature below thecritical range under suitable conditions, to prevent injury by too rapid cooling.6. General Requirements6.1 Material furnished under this specification shall conform to the applicable requirements of the current edition ofSpecificati
30、on A29/A29M, unless otherwise provided for in this specification.7. Chemical Requirements7.1 The heat analysis shall conform to the requirements as to chemical composition prescribed in Table 1 for the grade specifiedby the purchaser.A914/A914M 1628. Grain Size Requirements8.1 The steel shall have a
31、n austenitic grain size of five to eight. The grain structure shall be considered satisfactory when aminimum of 70 % of the rated grains are within the specified size limits.8.2 Hardenability values specified are based on fine-grain steels and are not applicable to coarse-grain steel.9. End-Quench H
32、ardenability Requirements9.1 The end-quench hardenability shall conform to the requirements specified on the purchase order.9.2 Hardenability values shall be specified in accordance with the applicable values in Figs. 2-23, inclusive, for the gradespecified.10. Test Specimens10.1 Number and Location
33、The number and location of test specimens shall be in accordance with the manufacturers standardpractice and shall adequately represent the hardenability of each heat.10.2 Thermal TreatmentAll forged and rolled hardenability test specimens must be normalized prior to testing. Castspecimens need not
34、be normalized.11. Test Methods11.1 Grain SizeTest Methods E112.11.2 End-Quench HardenabilityTest Method A255.12. Certification and Reports of Testing12.1 The hardenability shall be reported by listing hardness values at the following distances from the quenched end of the testspecimen:12.1.1 For inc
35、h-pound units (J distance in sixteenths of an inch): 1 through 16 sixteenths, then 18, 20, 22, 24, 28, and 32sixteenths of an inch.12.1.2 For SI units (J distance in millimetres): 1.5, 3, 5, 7, 9, 11, 13, 15, 20, 25, 30, 35, 40, 45, and 50 mm.13. Keywords13.1 bars; restricted hardenabilityA914/A914M
36、 163TABLE 1 Chemical Requirements of Restricted Hardenability SteelsNOTE 1Phosphorus and sulfur in open-hearth steel is 0.035 %, max, and 0.040 %, max respectively. Phosphorus and sulfur in electric-furnace steelis 0.025 %, max.NOTE 2Small quantities of certain elements are present in alloy steels t
37、hat are not specified or required. These elements are considered as incidentaland may be present to the following maximum amounts: copper, 0.35 %; nickel, 0.25 %; chromium, 0.20 %; molybdenum, 0.06 %.NOTE 3Chemical ranges and limits shown in this table are subject to the permissible variation for pr
38、oduct analysis shown in Specification A29/A29M.GradeDesignationChemical Composition, %Carbon Manganese Silicon Nickel Chromium Molybdenum15B21RHA 0.170.22 0.801.10 0.150.3515B35RHA 0.330.38 0.801.10 0.150.353310RH 0.080.13 0.400.60 0.150.35 3.253.75 1.401.754027RH 0.250.30 0.700.90 0.150.35 . . . .
39、. . 0.200.304118RH 0.180.23 0.700.90 0.150.35 . . . 0.400.60 0.080.154120RH 0.180.23 0.901.20 0.150.35 . . . 0.400.60 0.130.204130RH 0.280.33 0.400.60 0.150.35 . . . 0.801.10 0.150.254140RH 0.380.43 0.751.00 0.150.35 . . . 0.801.10 0.150.254145RH 0.430.48 0.751.00 0.150.35 . . . 0.801.10 0.150.25416
40、1RH 0.560.64 0.751.00 0.150.35 . . . 0.700.90 0.250.354320RH 0.170.22 0.450.65 0.150.35 1.652.00 0.400.60 0.200.304620RH 0.170.22 0.450.65 0.150.35 1.652.00 . . . 0.200.304820RH 0.180.23 0.500.70 0.150.35 3.253.75 . . . 0.200.3050B40RHA 0.380.43 0.751.00 0.150.35 . . . 0.400.605130RH 0.280.33 0.700.
41、90 0.150.35 . . . 0.801.10 . . .5140RH 0.380.43 0.700.90 0.150.35 . . . 0.700.90 . . .5160RH 0.560.64 0.751.00 0.150.35 . . . 0.700.90 . . .8620RH 0.180.23 0.700.90 0.150.35 0.400.70 0.400.60 0.150.258622RH 0.200.25 0.700.90 0.150.35 0.400.70 0.400.60 0.150.258720RH 0.180.23 0.700.90 0.150.35 0.400.
42、70 0.400.60 0.200.308822RH 0.200.25 0.751.00 0.150.35 0.400.70 0.400.60 0.300.409310RH 0.080.13 0.450.65 0.150.35 3.003.50 1.001.40 0.080.15A These steels can be expected to have 0.0005 to 0.003 % boron.A914/A914M 164FIG. 1 Comparison of H-Band and RH-Band for 4140 SteelAA914/A914M 165FIG. 2 Limits
43、for Hardenability Band 15B21 RHA914/A914M 166FIG. 3 Limits for Hardenability Band 15B35 RHA914/A914M 167FIG. 4 Limits for Hardenability Band 3310 RHA914/A914M 168FIG. 5 Limits for Hardenability Band 4027 RHA914/A914M 169FIG. 6 Limits for Hardenability Band 4118 RHA914/A914M 1610FIG. 7 Limits for Har
44、denability Band 4120 RHA914/A914M 1611FIG. 8 Limits for Hardenability Band 4130 RHA914/A914M 1612FIG. 9 Limits for Hardenability Band 4140 RHA914/A914M 1613FIG. 10 Limits for Hardenability Band 4145 RHA914/A914M 1614FIG. 11 Limits for Hardenability Band 4161 RHA914/A914M 1615FIG. 12 Limits for Harde
45、nability Band 4320 RHA914/A914M 1616FIG. 13 Limits for Hardenability Band 4620 RHA914/A914M 1617FIG. 14 Limits for Hardenability Band 4820 RHA914/A914M 1618FIG. 15 Limits for Hardenability Band 50B40 RHA914/A914M 1619FIG. 16 Limits for Hardenability Band 5130 RHA914/A914M 1620FIG. 17 Limits for Hard
46、enability Band 5140 RHA914/A914M 1621FIG. 18 Limits for Hardenability Band 5160 RHA914/A914M 1622FIG. 19 Limits for Hardenability Band 8620 RHA914/A914M 1623FIG. 20 Limits for Hardenability Band 8622 RHA914/A914M 1624FIG. 21 Limits for Hardenability Band 8720 RHA914/A914M 1625FIG. 22 Limits for Hard
47、enability Band 8822 RHA914/A914M 1626FIG. 23 Limits for Hardenability Band 9310 RHA914/A914M 1627SUMMARY OF CHANGESCommittee A01 has identified the location of selected changes to this standard since the last issue(A914/A914M92(2011) that may impact the use of this standard. (Approved Dec. 1, 2016)(
48、1) In 5.1, removed “open-hearth” from the first sentence.(2) In Table 1, removed the first sentence of Note 1.(3) Inserted new graphs for Fig. 11.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
49、 this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of thi
