1、Designation: A 914/A 914M 92 (Reapproved 2005)Standard Specification forSteel Bars Subject to Restricted End-Quench HardenabilityRequirements1This standard is issued under the fixed designationA 914/A 914M; the number immediately following the designation indicates the yearof original adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon (e) 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 at
3、tain 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 positio
4、n on the end-quench hardenability bar and notgreater than 65 % of the hardness range for standard H-bandsteels (Specification A 304) in the inflection region. Generallythe restricted hardenability band follows the middle of thecorresponding standard H-band. An example of the RH bandcompared with the
5、 H band is given for Grade 4140 in Fig. 1.1.3 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:2A 29/A 29M Spe
6、cification for Steel Bars, Carbon andAlloy,Hot-Wrought, General Requirements forA 255 Test Method for Determining Hardenability of SteelA 304 Specification for Carbon and Alloy Steel Bars, Sub-ject to End-Quench Hardenability RequirementsE112 Test Methods for Determining Average Grain Size2.2 SAE St
7、andards: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 to ha
8、rdenunder 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 standardizedque
9、nch. 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 mate
10、rial (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, and4.1.11 E
11、nd 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, inc
12、ludingthe suffix letters “RH”, in accordance with Table 1.4.3 Band limits 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, eit
13、herin inch-pound units (sixteenths of an inch) or in SI units(millimetres). Values below 20 HRC are not specified becausesuch values are not accurate.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of S
14、ubcommitteeA01.15 on Bars.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as A 914/A 914M -92(1999)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
15、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
16、hohocken, PA 19428-2959, United States.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 “Ap-proximate Diameter of Rounds with S
17、ame 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, RH-band steels shall exhibithardness w
18、ithin 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 % martensite for theminimum and maximum specifi
19、ed 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 critical locations ofthe Jominy hardenabi
20、lity 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 consecutive316-in. or 5-mm Jominy dis
21、tance 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 hardness not less than43 HRC, but the maxi
22、mum 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 test bar ischosen as the exception).
23、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, the test bar must exhibithardness not g
24、reater 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-lowed by secondary melting using ele
25、ctroslag 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 temperature belowthe critical range under
26、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 A 29/A 29M, unless otherwise provided for inthis specification.7. Chemical Requiremen
27、ts7.1 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 be considered satisfactory whena mi
28、nimum 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 conform to therequirements specified on t
29、he 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 manufacturersstandard practice and
30、 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-Quench HardenabilityTest Method A
31、255.12. 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 sixteenths, then 18, 20, 22, 24, 28, and
32、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 hardenabilityA 914/A 914M 92 (2005)2TABLE 1 Chemical Requirements of Restricted Hardenability SteelsNOTE 1Phosphorus and sulfur in
33、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 incidentaland may be present to
34、 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 SpecificationA 29/A 29M.GradeDesignationChemical Composition, %Carbon Manga
35、nese 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 0.080.154120RH 0.180.23 0.901.20 0.150.
36、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 0.450.65 0.150.35 1.652.00 0.4
37、00.60 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 . . . 0.700.90 . . .5160RH 0.560.64
38、 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 0.300.409310RH 0.080.13 0.450
39、.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.A 914/A 914M 92 (2005)3FIG. 1 Comparison of H-Band and RH-Band for 4140 SteelAA 914/A 914M 92 (2005)4FIG. 2 Limits for Hardenability Band 15B21 RHA 914/A 914M 92 (2005)5FIG. 3 Limits for Hardenabilit
40、y Band 15B35 RHA 914/A 914M 92 (2005)6FIG. 4 Limits for Hardenability Band 3310 RHA 914/A 914M 92 (2005)7FIG. 5 Limits for Hardenability Band 4027 RHA 914/A 914M 92 (2005)8FIG. 6 Limits for Hardenability Band 4118 RHA 914/A 914M 92 (2005)9FIG. 7 Limits for Hardenability Band 4120 RHA 914/A 914M 92 (
41、2005)10FIG. 8 Limits for Hardenability Band 4130 RHA 914/A 914M 92 (2005)11FIG. 9 Limits for Hardenability Band 4140 RHA 914/A 914M 92 (2005)12FIG. 10 Limits for Hardenability Band 4145 RHA 914/A 914M 92 (2005)13FIG. 11 Limits for Hardenability Band 4161 RHA 914/A 914M 92 (2005)14FIG. 12 Limits for
42、Hardenability Band 4320 RHA 914/A 914M 92 (2005)15FIG. 13 Limits for Hardenability Band 4620 RHA 914/A 914M 92 (2005)16FIG. 14 Limits for Hardenability Band 4820 RHA 914/A 914M 92 (2005)17FIG. 15 Limits for Hardenability Band 50B40 RHA 914/A 914M 92 (2005)18FIG. 16 Limits for Hardenability Band 5130
43、 RHA 914/A 914M 92 (2005)19FIG. 17 Limits for Hardenability Band 5140 RHA 914/A 914M 92 (2005)20FIG. 18 Limits for Hardenability Band 5160 RHA 914/A 914M 92 (2005)21FIG. 19 Limits for Hardenability Band 8620 RHA 914/A 914M 92 (2005)22FIG. 20 Limits for Hardenability Band 8622 RHA 914/A 914M 92 (2005
44、)23FIG. 21 Limits for Hardenability Band 8720 RHA 914/A 914M 92 (2005)24FIG. 22 Limits for Hardenability Band 8822 RHA 914/A 914M 92 (2005)25FIG. 23 Limits for Hardenability Band 9310 RHA 914/A 914M 92 (2005)26ASTM International takes no position respecting the validity of any patent rights asserted
45、 in connection with any item mentionedin this standard. Users of 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
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47、areful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Internati
48、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A 914/A 914M 92 (2005)27
