1、Designation: A 355 89 (Reapproved 2006)Standard Specification forSteel Bars, Alloys, for Nitriding1This standard is issued under the fixed designation A 355; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers alloy steel bars, suitable forsurface hardening by nitriding, designated as Classes A, B, C,and D. Class
3、 A and Class D bars are general-purpose bars;Class B bars are free-machining bars; Class C bars contain3.50 % nickel and are characterized by higher core strength.All classes are normally furnished in the hot-rolled, quenched,and tempered condition. However, centerless-ground or turnedbars, in any o
4、f the classes, may be specified by the purchaser.Also, as-rolled, annealed, or unannealed bars suitable forforging may be purchased to this specification. When as-rolled,annealed, or unannealed bars are furnished, Sections 6, 10, and11 are not applicable.1.2 The values stated in inch-pound units are
5、 to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2. Referenced Documents2.1 ASTM Standards:2A 29/A 29M Specification for Steel Bars, Carbon andAlloy,Hot-Wrought, General Requireme
6、nts for3. Ordering Information3.1 Orders under this specification should include the fol-lowing as required to adequately describe the desired materials:3.1.1 Quantity (weight or number of pieces),3.1.2 Name of material (alloy steel bars, for nitriding),3.1.3 Surface finish (Section 14),3.1.4 Cross-
7、sectional shape,3.1.5 Size,3.1.6 Length (Section 13),3.1.7 Class (Section 1),3.1.8 Thermal treatment (Section 6),3.1.9 Hardness (Section 11),3.1.10 Microstructure when desired (Section 7),3.1.11 Report of ladle analysis if desired (Section 9),3.1.12 Straightness (Section 10),3.1.13 ASTM designation
8、A 355, and3.1.14 End use, exceptions to the specification, or specialrequirements.4. Process4.1 The steel shall be made by the electric-furnace processonly.5. Discard5.1 Sufficient discard shall be made from each ingot toensure freedom from injurious piping and undue segregation.6. Quenching and Tem
9、pering6.1 The bars shall be given a liquid quench followed by atempering treatment at a temperature not lower than 600C(1112F) to produce a fine spheroidized structure.7. Microstructure7.1 When specified the microstructure resulting from theheat treatment specified in Section 6 shall not show free f
10、erritein amounts exceeding those prescribed in Table 1. Otherpercentages of free ferrite may be supplied by agreementbetween the manufacturer and the purchaser.7.2 The amount of free ferrite shall be determined bymetallographic examination under suitable magnification of aspecimen from the bars in t
11、he quenched and tempered condi-tion. The number and location of tests and details of the basisof establishing free ferrite shall be as agreed upon between themanufacturer and the purchaser.8. Decarburization8.1 The maximum depth of total and partial decarburizationof hot-rolled bars and heat-treated
12、 bars shall not exceed theamounts prescribed in Table 2.8.2 Centerless-ground or turned bars shall be free from totaland partial decarburization.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys, and is the direct responsibility of Subcom
13、mitteeA01.15 on Bars.Current edition approved March 1, 2006. Published March 2006. Originallyapproved in 1952. Last previous edition approved in 2000 as A 355 89 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annua
14、l Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.9. Heat Analysis9.1 The steel shall conform to the requirements as to cast or
15、heat (formerly ladle) analysis prescribed in Table 3.10. Straightness10.1 Unless otherwise specified, all material shall be sup-plied to a maximum straightness tolerance of18 in. (3.18 mm)in any 5 ft (1.5 m) but it may not exceed the following:Maximum straightness deviation, in. =18 3 (length in fee
16、t)/511. Hardness Test11.1 The hardness of the steel after quenching and temper-ing shall conform to one of the ranges as specified in Table 4.12. Permissible Variations in Dimensions12.1 The hot-rolled bars shall not vary from the specifieddimensions by more than the amounts prescribed in Specifica-
17、tion A 29/A 29M.12.2 The diameter of centerless ground bars shall not varyfrom that specified by more than the following:Specified Diameter, in. (mm)PermissibleVariations,Over or Under,in. (mm)Under14 (6.35) 0.0005 (0.013)14 to1112 (6.35 to 8.73), incl 0.001 (0.025)Over1132 to1932 (8.73 to 15.08), i
18、ncl 0.0015 (0.038)Over1932 to 1332 (15.08 to 27.78), incl 0.002 (0.051)Over 1332 (27.78) 0.0025 (0.064)12.3 The diameter of turned bars shall not vary from thatspecified by more than the following:Specified Diameter, in. (mm)PermissibleVariations,Over or Under,in. (mm)2 (51) and under 0.005 (0.13)Ov
19、er 2 to 4 (51 to 102), incl 0.0075 (0.19)Over 4 (102) 0.010 (0.25)13. Length13.1 Unless otherwise specified, the bars shall be furnishedin lengths of 8 to 12 ft (2.4 to 3.7 m). However, 10 % of thebars will be accepted in shorter lengths, but in no case shall thelengths be less than 5 ft (1.5 m).14.
20、 Workmanship, Finish, and Appearance14.1 Hot-rolled bars shall be sound, and commercially freeof excessive scale, cracks, seams, and other injurious imper-fections.14.2 Centerless-ground or turned bars shall have a cleansmooth surface and shall be oiled to prevent rusting.15. General Requirements15.
21、1 Material furnished under this specification shall con-form to the requirements of the current edition of SpecificationA 29/A 29M unless otherwise provided for herein.16. Keywords16.1 alloy steel bars; nitriding steel; steel barsTABLE 1 Permissible Free FerriteDiameter or Thickness, in. (mm)Permiss
22、ible FreeFerrite Area,max, %1.00 (25.4) and under 2Over 1.00 to 3.00 (25.4 to 76.2), incl 4Over 3.00 (76.2) 6TABLE 2 Permissible Depth of DecarburizationDiameter or Distance BetweenParallel Faces, in. (mm)Depth of Decarburization,max, in. (mm)12 (12.7) and under 0.030 (0.76)Over12 to 1 (12.7 to 25.4
23、), incl 0.035 (0.89)Over 1 to 112 (25.4 to 38.1), incl 0.040 (1.02)Over 112 to 2 (38.1 to 50.8), incl 0.050 (1.27)Over 2 to 212 (50.8 to 63.5), incl 0.060 (1.52)Over 212 to 3 (63.5 to 76.2), incl 0.070 (1.78)Over 3 to 5 (76.2 to 127.0), incl 0.085 (2.16)Over 5 to 8 (127.0 to 203.2), incl 0.125 (3.18
24、)TABLE 3 Chemical RequirementsClass A Class B Class C Class DCarbon, % 0.380.43 0.350.40 0.220.27 0.330.38Manganese, % 0.500.70 0.700.95 0.500.70 0.500.70Phosphorus, max, % 0.035 0.035 0.035 0.035Sulfur, max, % 0.040 0.060 0.040 0.040Silicon, % 0.150.35 0.150.35 0.150.35 0.150.35Chromium, % 1.401.80
25、 1.201.50 1.001.35 1.001.30Aluminum, % 0.951.30 0.951.30 0.951.30 0.951.30Molybdenum, % 0.300.40 0.150.25 0.200.30 0.150.25Selenium, % . . . 0.150.25 . . . . . .Nickel, % . . . 3.253.75 . . .TABLE 4 Hardness RequirementsHardness ScaleHardnessRange 1 Range 2Brinell 223 to 269 248 to 302Rockwell C 19
26、to 28 24 to 32Rockwell B 98 to 104 101 to 107A 355 89 (2006)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such p
27、atent 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 e
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29、r hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 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 355 89 (2006)3
