1、Designation: A914/A914M 92 (Reapproved 2011)Standard 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 adoption or, in t
2、he 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. Scope1.1 This specification covers hot-worked alloy and carbon-boron steels designed to attain
3、 restricted depth of hardening inthe end-quench test. These steel compositions are identified bythe suffix letter “RH” added to the conventional grade number.1.2 In general, steels with restricted hardenability (RHsteels) will exhibit a hardness range not greater than 5 HRC atthe initial position on
4、 the end-quench hardenability bar and notgreater than 65 % of the hardness range for standard H-bandsteels (Specification A304) in the inflection region. Generallythe restricted hardenability band follows the middle of thecorresponding standard H-band. An example of the RH bandcompared with the H ba
5、nd is given for Grade 4140 in Fig. 1.1.2.1 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two sys
6、tems may result in non-conformancewith the standard.1.3 This specification is expressed in both inch-pound unitsand SI units. However, the material will be supplied toinch-pound units unless the purchase order specifies the “M”specification designation.2. Referenced Documents2.1 ASTM Standards:2A29/
7、A29M Specification for Steel Bars, Carbon and Alloy,Hot-Wrought, General Requirements forA255 Test Methods for Determining Hardenability of SteelA304 Specification for Carbon andAlloy Steel Bars Subjectto End-Quench Hardenability RequirementsE112 Test Methods for Determining Average Grain Size2.2 SA
8、E Standards:3J 406 Methods of Determining Hardenability of SteelsJ 1268 Hardenability Bands for Carbon and Alloy H SteelsJ 1868 Restricted Hardenability Bands for Selected AlloySteels3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 hardenabilitythe relative ability of a steel t
9、o hardenunder heat treatment becomes apparent in the degree to whichthe material hardens when quenched at different cooling rates.3.1.1.1 DiscussionHardenability is measured quantita-tively, usually by noting the extent or depth of hardening of astandard size and shape test specimen in a standardize
10、dquench. In the end-quench test the depth of hardening is thedistance along the specimen from the quenched end to a givenhardness.4. Ordering Information4.1 Orders for material under this specification shouldinclude the following information, in proper sequence:4.1.1 Quantity (weight),4.1.2 Name of
11、material (alloy or carbon-boron steel),4.1.3 Cross-sectional shape,4.1.4 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.
12、11 End use or special requirements.NOTE 1A typical ordering description is as follows: 10 000 lb, alloybars, round, 4.0-in. diameter by 10 ft, Grade 4140RH, heat analysisrequired, complete hardenability data required,ASTMAXXX, AXXXMdated _ worm gear.4.2 The purchaser shall specify the desired grade,
13、 includingthe suffix letters “RH”, in accordance with Table 1.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.15 on Bars.Current edition approved April 1, 2011. Published June 2011. Or
14、iginallyapproved in 1992. Last previous edition approved in 2005 as A914/A914M - 92(2005). DOI: 10.1520/A0914_A0914M-92R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
15、fer to the standards Document Summary page onthe ASTM website.3Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001, http:/www.sae.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 Band limits
16、are shown graphically and as tabulations inFigs. 2-23, inclusive. For specification purposes, one must usetabulated values of Rockwell hardness (HRC) as a function ofdistance from the quenched end of the hardenability bar, eitherin inch-pound units (sixteenths of an inch) or in SI units(millimetres)
17、. Values below 20 HRC are not specified becausesuch values are not accurate.4.3.1 Band limits shown graphically are so depicted forconvenience in estimating the hardness values at variousintermediate locations on the end quench test bar for quickcomparisons of the various RH grades. The values of “A
18、p-proximate Diameter of Rounds with Same As-Quenched Hard-ness” shown above each RH-band, were selected from rangesappearing in Fig. 7 of SAE J 406. The RH-bands are presentedgraphically, with distances from the quenched end in bothinch-pound units and also SI units.4.4 For specification purposes, R
19、H-band steels shall exhibithardness within the minimum and maximum HRC rangespecified at the J1 (J1.5-mm) position and shall meet oneadditional minimum and one additional maximum value. Inthis specification, the two additional hardness values shallrepresent the approximate hardness for 50 % martensi
20、te for theminimum and maximum specified carbon content, respectively(except where hardenability is too high; then the two additionalhardness control values shall be five HRC points below themaximum hardness value specified at the J1 (J1.5-mm) posi-tion).4.4.1 In general, these points define the crit
21、ical locations ofthe Jominy hardenability band for purposes of characterizingheat treatment response. The four specification points arecircled in the tables of hardness versus Jominy distance and onthe RH-bands. For all other Jominy positions, a tolerance oftwo points HRC is permitted for a maximum
22、consecutive316-in. or 5-mm Jominy distance on the restricted hardenabilityband.4.4.2 For example, referring to Fig. 9, a hardenability testbar of a steel meeting the requirements for 4140RH mustexhibit a hardness at J1 not less than 54 HRC, nor more than59 HRC.At J12, the test bar must exhibit hardn
23、ess not less than43 HRC, but the maximum hardness can be as high as 52 HRC(or even 54 HRC if the region of the test bar is chosen as theexception). At J20, the bar must exhibit hardness not greaterthan 47 HRC, but the minimum hardness can be as low as 37HRC (or as low as 35 HRC if this region of the
24、 test bar ischosen as the exception).4.4.3 A similar example, referring to Fig. 9, for 4140RHwith distances from the quenched end in millimetres wouldlimit hardness at J1.5 mm to not less than 54 HRC nor morethan 59 HRC.At J20 mm, the test bar must exhibit hardness notless than 42 HRC. At J30 mm, th
25、e test bar must exhibithardness not greater than 48 HRC.5. Manufacture5.1 Melting PracticeThe steel shall be made by one ormore of the following primary processes: open-hearth, basic-oxygen, or electric furnace. The primary melting may incor-porate separate degassing or ladle refining and may be fol
26、-lowed by secondary melting using electroslag remelting orvacuum arc remelting. Where secondary melting is employed,the heat shall be defined as all the ingots remelted from a singleprimary heat.5.2 Slow CoolingImmediately after hot working, the barsshall be allowed to cool when necessary to a tempe
27、rature belowthe critical range under suitable conditions, to prevent injury bytoo rapid cooling.6. General Requirements6.1 Material furnished under this specification shall con-form to the applicable requirements of the current edition ofSpecification A29/A29M, unless otherwise provided for in thiss
28、pecification.7. Chemical Requirements7.1 The heat analysis shall conform to the requirements asto chemical composition prescribed in Table 1 for the gradespecified by the purchaser.8. Grain Size Requirements8.1 The steel shall have an austenitic grain size of five toeight. The grain structure shall
29、be considered satisfactory whena minimum of 70 % of the rated grains are within the specifiedsize limits.8.2 Hardenability values specified are based on fine-grainsteels and are not applicable to coarse-grain steel.9. End-Quench Hardenability Requirements9.1 The end-quench hardenability shall confor
30、m to therequirements specified on the purchase order.9.2 Hardenability values shall be specified in accordancewith the applicable values in Figs. 2-23, inclusive, for the gradespecified.10. Test Specimens10.1 Number and LocationThe number and location oftest specimens shall be in accordance with the
31、 manufacturersstandard practice and shall adequately represent the harden-ability of each heat.10.2 Thermal TreatmentAll forged and rolled hardenabil-ity test specimens must be normalized prior to testing. Castspecimens need not be normalized.11. Test Methods11.1 Grain SizeTest Methods E112.11.2 End
32、-Quench HardenabilityTest Method A255.12. Certification and Reports of Testing12.1 The hardenability shall be reported by listing hardnessvalues at the following distances from the quenched end of thetest specimen:12.1.1 For inch-pound units (J distance in sixteenths of aninch): 1 through 16 sixteen
33、ths, 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 92 (2011)2TABLE 1 Chemical Requirements of Restricted Hardenability Steel
34、sNOTE 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 that are not specified or required. These elements are considered as
35、 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 product analysis shown in SpecificationA29/A29M.GradeDesignationChemi
36、cal Composition, %Carbon Manganese Silicon Nickel Chromium Molybdenum15B21RHA0.170.22 0.801.10 0.150.3515B35RHA0.330.38 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 . . . . . . 0.200.304118RH 0.180.23 0.700.90 0.150.35 . . . 0.400.60 0.080.154
37、120RH 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 0.150.254161RH 0.560.64 0.751.00 0.150.35 . . . 0.700.90 0.250.354320RH 0.170.22
38、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 . . . 0.200.3050B40RHA0.380.43 0.751.00 0.150.35 . . . 0.400.605130RH 0.280.33 0.700.90 0.150.35 . . . 0.801.10 . . .5140RH 0.380.43 0.700.90 0.150.35 . . .
39、 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 0.400.70 0.400.60 0.200.308822RH 0.200.25 0.751.00 0.150.35 0.400.70 0.400.60
40、 0.300.409310RH 0.080.13 0.450.65 0.150.35 3.003.50 1.001.40 0.080.15AThese steels can be expected to have 0.0005 to 0.003 % boron.A914/A914M 92 (2011)3FIG. 1 Comparison of H-Band and RH-Band for 4140 SteelAA914/A914M 92 (2011)4FIG. 2 Limits for Hardenability Band 15B21 RHA914/A914M 92 (2011)5FIG. 3
41、 Limits for Hardenability Band 15B35 RHA914/A914M 92 (2011)6FIG. 4 Limits for Hardenability Band 3310 RHA914/A914M 92 (2011)7FIG. 5 Limits for Hardenability Band 4027 RHA914/A914M 92 (2011)8FIG. 6 Limits for Hardenability Band 4118 RHA914/A914M 92 (2011)9FIG. 7 Limits for Hardenability Band 4120 RHA
42、914/A914M 92 (2011)10FIG. 8 Limits for Hardenability Band 4130 RHA914/A914M 92 (2011)11FIG. 9 Limits for Hardenability Band 4140 RHA914/A914M 92 (2011)12FIG. 10 Limits for Hardenability Band 4145 RHA914/A914M 92 (2011)13FIG. 11 Limits for Hardenability Band 4161 RHA914/A914M 92 (2011)14FIG. 12 Limit
43、s for Hardenability Band 4320 RHA914/A914M 92 (2011)15FIG. 13 Limits for Hardenability Band 4620 RHA914/A914M 92 (2011)16FIG. 14 Limits for Hardenability Band 4820 RHA914/A914M 92 (2011)17FIG. 15 Limits for Hardenability Band 50B40 RHA914/A914M 92 (2011)18FIG. 16 Limits for Hardenability Band 5130 R
44、HA914/A914M 92 (2011)19FIG. 17 Limits for Hardenability Band 5140 RHA914/A914M 92 (2011)20FIG. 18 Limits for Hardenability Band 5160 RHA914/A914M 92 (2011)21FIG. 19 Limits for Hardenability Band 8620 RHA914/A914M 92 (2011)22FIG. 20 Limits for Hardenability Band 8622 RHA914/A914M 92 (2011)23FIG. 21 L
45、imits for Hardenability Band 8720 RHA914/A914M 92 (2011)24FIG. 22 Limits for Hardenability Band 8822 RHA914/A914M 92 (2011)25FIG. 23 Limits for Hardenability Band 9310 RHA914/A914M 92 (2011)26ASTM International takes no position respecting the validity of any patent rights asserted in connection wit
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