A 730 – 93 (Reapproved 1999) Designation A 730 – 93 (Reapproved 1999) Standard Specification for Forgings, Carbon and Alloy Steel, for Railway Use1 This standard is issued under the fixed designation[.]
Designation: A 730 – 93 (Reapproved 1999) Standard Specification for Forgings, Carbon and Alloy Steel, for Railway Use1 This standard is issued under the fixed designation A 730; the number immediately following the designation indicates the year of original adoption or, in 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 Scope 1.1 This specification covers eight grades of untreated and heat-treated carbon steel forgings and six grades of heat-treated alloy steel forgings for railway use Current Grade A B C D E F G H I J K L M N NOTE 1—It is recommended, when semi-finished steel is desired to process these forgings, that the latest issue of ASTM Specification A 711, for Carbon and Alloy Steel Blooms, Billets, and Slabs for Forging,2 be used This will enable the forger to select semi-finished material of such chemistry as he desires NOTE 2—Railway axles are covered by Specification A 21 1.2 The grades of carbon steel forgings and the purposes for which they are frequently used are as follows, the choice depending on design and stress or service to be imposed: 1.2.1 Grade A is untreated and is mostly used for drop forgings and parts of minor importance, and those which are to be case hardened 1.2.2 Grade B is untreated and is used for a general group of miscellaneous ordinary forgings where heat treatment is not deemed necessary 1.2.3 Grade C is annealed, normalized, or normalized and tempered 1.2.4 Grade D is annealed, normalized, or normalized and tempered 1.2.5 Grade E is normalized and tempered 1.2.6 Grade F is double normalized and tempered 1.2.7 Grade G is quenched and tempered 1.2.8 Grade H is normalized, quenched, and tempered 1.2.9 Grades E, F, G, and H forgings are used in high-duty service on locomotives, cars, and other equipment 1.3 The grades of alloy steel forgings are as follows: 1.3.1 Grades I, J, and K are normalized and tempered 1.3.2 Grades L, M, and N are normalized, quenched, and tempered, and are used in heavy-duty service on locomotives, cars, and special equipment Former Designation and Grade A 236, A A 236, B A 236, C A 236, D A 236, E A 236, F A 236, G A 236, H A 238, A A 238, B A 238, C A 238, D A 238, E A 238, F 1.4 Supplementary Requirements (Sections S1 to S5) of an optional nature are provided These shall apply only when specified by the purchaser 1.5 The values stated in inch-pound units are to be regarded as the standard Referenced Documents 2.1 ASTM Standards: A 21 Specification for Carbon Steel Axles, Non-HeatTreated and Heat-Treated, for Railway Use2 A 370 Test Methods and Definitions for Mechanical Testing of Steel Products3 A 711 Specification for Steel Forging Stock4 E 112 Test Methods for Determining the Average Grain Size5 E 381 Method of Macroetch Testing Steel Bars, Billets, Blooms, and Forgings5 Ordering Information 3.1 The purchaser shall specify in the inquiry, contract, and order the grade of steel desired, and any restrictive modifications of this specification 3.2 Supplementary requirements are provided and shall apply only when specified in the purchase order NOTE 3—The forgings described above were formerly designated as follows: Manufacture 4.1 Melting Process—The steel shall be made by one or more of the following processes: open-hearth, basic-oxygen, or electric-furnace This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee A01.06 on Steel Forgings and Billets Current edition approved Dec 15, 1993 Published February 1994 Originally published as A 730–76 to replace A 236 and A 238 Last previous edition A 730–81(1988) Annual Book of ASTM Standards, Vol 01.04 Annual Book of ASTM Standards, Vol 01.03 Annual Book of ASTM Standards, Vol 01.05 Annual Book of ASTM Standards, Vol 03.01 Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States A 730 – 93 (1999) 4.2 Discard—Sufficient discard shall be made to assure freedom from piping and undue segregation 4.3 Forging Practice—The forgings may be made direct from the ingot or from blooms The total reduction from ingot or strand cast bloom to forging shall not be less than to 1, unless otherwise specified 4.4 Cooling and Heating: 4.4.1 After carbon steel blooms are produced, they shall be allowed to cool uniformly and shall not be subject to contact with water or drafts 4.4.2 After alloy steel blooms are produced, they shall be cooled in closed containers, hoods, or furnaces 4.4.3 Blooms shall be reheated for forging in a manner that will prevent internal bursts and overheating 4.4.4 Forgings (Grades C through N) shall be slow cooled in closed containers, covered conveyors, or hoods If forgings (Grades C through N) are heat treated directly from forging, they shall be slow cooled following the final heat treatment 4.4.5 Forgings (Grades C through N) that are heat treated directly from forging (1) shall be cooled below the transformation temperature or to approximately 1000°F (538°C) before any reheating operation, and (2) must not be permitted to cool below 500°F (260°C) without slow cooling as defined in 4.4.4 4.6.1 Forgings for heat treatment shall be reheated gradually and uniformly to the proper temperature to refine the grain and shall be held at this temperature for a sufficient time to effect the desired change 4.6.2 Annealing—After heating to a suitable temperature the forgings shall be allowed to cool slowly and uniformly A furnace charge thus treated is termed an annealing charge 4.6.3 Normalizing—After heating to a suitable temperature, the forgings shall be withdrawn from the furnace and allowed to cool uniformly in air A furnace charge thus treated is termed a normalizing charge Cooling may be accelerated by increased air circulation, which must be controlled to provide reasonably uniform cooling 4.6.4 Double Normalizing—The procedure shall consist of two separate heat treatments The second treatment shall be performed at a lower temperature than the first A furnace charge thus treated is termed a double-normalizing charge Cooling may be accelerated by increased air circulation, which must be controlled to provide reasonably uniform cooling 4.6.5 Quenching—After heating to a suitable temperature, the forgings shall be quenched in a suitable medium under reasonably uniform conditions A furnace charge thus treated is termed a “quenching charge.” 4.6.6 Tempering—Forgings shall be reheated gradually to, and held at, a suitable temperature below the critical range and shall then be allowed to cool under suitable conditions A furnace charge thus treated is termed a “tempering charge.” 4.6.7 Heat treatment may be performed in either batch-type furnaces or continuous furnaces 4.7 Straightening: 4.7.1 Straightening of forgings shall be done before machining and in such a manner as to leave the surface free of injurious scars 4.7.2 Straightening preferably shall be performed at a temperature no lower than 950°F (510°C) Straightening performed at temperatures lower than 950°F shall be followed by stress relieving or applicable heat treatment NOTE 4—As the temperature of the forgings approaches the minimum of 500°F (260°C) a supplemental heat source may be necessary to assure an effective slow cooling cycle 4.4.6 When properly vacuum degassed steel is used, the slow cooling requirements of 4.4.2, 4.4.4 and item (2) of 4.4.5 may be omitted, but forging blooms must then be pile cooled 4.5 Boring: 4.5.1 Boring, if specified under Supplementary Requirement S5, shall be performed before normalizing or quenching in the case of normalized and tempered or quenched and tempered forgings, and before either normalizing or quenching, in the case of normalized, quenched, and tempered forgings 4.5.2 For quenched and tempered forgings or normalized, quenched and tempered forgings it is recommended, but not mandatory, that all forgings over in (178 mm) in diameter be bored 4.5.3 For carbon steel no solid forgings over 10 in (254 mm) in diameter and no forgings over in (203 mm) in wall thickness shall be liquid quenched under this specification 4.5.4 In bored forgings, the diameter of the hole shall be a matter of agreement between the manufacturer and the purchaser 4.6 Heat Treatment: Chemical Requirements 5.1 Composition: 5.1.1 Carbon steel (Grades A through H) shall conform to the requirements for chemical composition prescribed in Table 5.1.2 Alloy steel (Grades I through N) shall conform to the following requirements for chemical composition: Phosphorus 0.045 max Sulfur 0.050 max TABLE Chemical Requirements for Carbon Steels Composition, % Elements Carbon Manganese Phosphorus, max Sulfur, max Silicon, Grades G and H Grade A Grade B Grades C, D, and E Grade F 0.15 max 0.30–0.60 0.045 0.050 0.15–0.25 0.30–0.60 0.045 0.050 0.40–0.55 0.60–0.90 0.045 0.050 0.15 0.45–0.59 0.60–0.90 0.045 0.050 0.15 0.60–0.90 0.045 0.050 0.15 A 730 – 93 (1999) 6.1.3 The diameter of the test prolongation of forgings shall be the specified diameter or thickness of the forgings disregarding large ends or collars 6.1.4 Tests of forgings shall be made only after final heat treatment 6.2 Number of Specimens: 6.2.1 Test prolongations shall be attached to at least % of the forgings in each size classification in each heat in each heat treatment lot 6.2.2 Forgings may be used for test procurement if forgings with prolongations are not available or have been expended 6.2.3 Mechanical tests shall be made from each size classification shown in Table in each heat in each annealing or normalizing charge, or from each size classification in each heat in each normalizing or quenching charge represented in each tempering charge 6.2.4 Where batch-type heat treating furnaces are used, one test shall be made from each size classification shown in Table of each heat represented in each annealing or normalizing charge, or from each size classification in eachheat in each normalizing or quenching charge represented in each tempering charge 6.2.5 Where continuous heat-treating furnaces are used, one test shall be made from each grade from each size classification shown in Table represented by each heat The pieces represented by each test shall be designated a heat treatment lot, and each lot shall contain no more than 70 pieces from each heat 6.2.6 If any test specimen fails because of mechanical condition of the testing apparatus, it may be discarded and another specimen taken 6.3 Test Location and Orientation: 6.3.1 Test specimens shall be taken from the test prolongation or a forging in accordance with the provisions of 6.2 6.3.2 The axis of the specimen shall be located at any point midway between the center and surface of the solid forging or full-sized prolongation, or at any point midway between the inner and outer surfaces of the wall of bored forgings, and shall be parallel to the axis of the forging in the direction in which the metal is most drawn out 6.3.3 Test specimens shall conform to dimensions shown in Fig of Test Methods A 370 6.4 Test Method: 6.4.1 The yield point specified in Table for Grades C, D, E, F, I, and J may be determined by the drop of the beam or halt of the gage of the testing machine, or by the use of dividers Where a definite yield point is not exhibited, the yield strength defined in 6.4.2 shall be used 6.4.2 The yield strength specified in Table for Grades G, H, K, L, M, and N forgings shall be determined by a strain gage or extensometer reading to 0.0002 in (0.005 mm) Yield strength may be defined as the stress at 0.6 % total strain under load or as the stress at 0.2 % offset The procedure described in Test Methods A 370 shall be followed After the yield point has been passed, the extensometer may then be removed and the test continued to determine the tensile strength By agreement between purchaser and manufacturer, analysis may be required and limits established for elements not specified above 5.2 Cast or Heat Analysis: 5.2.1 An analysis of each cast or heat of carbon steel shall be made by the manufacturer to determine the percentages of carbon and the elements prescribed in Table The chemical composition thus determined shall be reported to the purchaser or his representative and shall conform to the requirements prescribed in Table 5.2.2 An analysis of each cast or heat of alloy steel shall be made by the manufacturer to determine the percentage of carbon, manganese, phosphorus, sulfur, and silicon; also the alloying elements agreed upon in accordance with 5.1.2 The chemical composition thus determined shall be reported to the purchaser or his representative and shall conform to the requirements specified and agreed upon in 5.1.2 5.3 Product Analysis: 5.3.1 An analysis may be made by the purchaser from a carbon steel forging representing each heat The chemical composition thus determined shall conform to the requirements in Table 1, subject to the tolerances shown in Table 5.3.2 An analysis may be made by the purchaser from an alloy steel forging representing each heat The chemical composition thus determined shall conform to the requirements of 5.1.2 subject to tolerances shown in Table 5.3.3 Samples for analysis may be taken from the forging or from a full-size prolongation, at any point midway between the center and surface when solid, or midway between the inner and outer surfaces of the wall when bored If drillings are taken, they shall be obtained by using a 5⁄8 -in (16-mm) diameter drill, or turnings may be taken from the test specimen Physical Requirements 6.1 Tensile Properties: 6.1.1 Carbon steel forgings (Grades C through H) and alloy steel forgings (Grades I through N) shall conform to the requirements prescribed in Table when tested in accordance with the latest issue of Test Methods A 370 6.1.2 The size classification of forgings shall be determined by the specified diameter or thickness of solid forgings disregarding large ends or collars or by the specified wall thickness of bored forgings that are heat treated after rough boring TABLE Permissible Variations for Product Analysis of Carbon Steels Permissible Variations, over the Maximum Limit or Under the Minimum Limit, % Elements Carbon (Grades A and B) Manganese Phosphorus Sulfur Silicon A 100 in.2 (645 cm2) and UnderA Over 100 to 400 in.2 (645 to 2581 cm2), inclA 0.02 0.03 0.008 0.008 0.02 0.04 0.05 0.010 0.010 0.02 Determine by cross section from which drillings are taken A 730 – 93 (1999) TABLE Permissible Variations for Product Analysis of Alloy Steels Variation Over Maximum Limit or Under Minimum Limit, % Elements Limit, or Maximum of Specified Element, % To 100 in (645 cm2) Over 100 to 200 in.2 (645 to 1290 cm2), incl Over 200 to 400 in.2 (1290 to 2580 cm2), incl Over 400 to 800 in.2 (2580 to 5160 cm2), incl Carbon To 0.30, incl Over 0.30 to 0.75, incl Over 0.75 0.01 0.02 0.03 0.02 0.03 0.04 0.03 0.04 0.05 0.01 0.05 0.06 Manganese To 0.90, incl Over 0.90 to 2.10, incl 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.07 Phosphorus Over maximum only 0.005 0.010 0.010 0.010 Sulfur To 0.060, incl 0.005 0.010 0.010 0.010 Silicon To 0.35, incl Over 0.35 to 2.20, incl 0.02 0.05 0.02 0.06 0.03 0.06 0.04 0.07 Nickel To 1.00, incl Over 1.00 to 2.00, incl Over 2.00 to 5.30, incl Over 5.30 to 10.00, incl 0.03 0.05 0.07 0.10 0.03 0.05 0.07 0.10 0.03 0.05 0.07 0.10 0.03 0.05 0.07 0.10 Chromium To 0.90, incl Over 0.90 to 2.10, incl Over 2.10 to 3.99 0.03 0.05 0.10 0.04 0.06 0.10 0.04 0.06 0.12 0.05 0.07 0.14 Molybdenum To 0.20, incl Over 0.20 to 0.40, incl Over 0.40 to 1.15, incl 0.01 0.02 0.03 0.01 0.03 0.04 0.02 0.03 0.05 0.03 0.04 0.06 Tungsten To 1.00, incl Over 1.00 to 4.00, incl 0.04 0.08 0.05 0.09 0.05 0.10 0.06 0.12 Vanadium To 0.10, incl Over 0.10 to 0.25, incl Over 0.25 to 0.50, incl Minimum value specified, check under minimum limit 0.01 0.02 0.03 0.01 0.01 0.02 0.03 0.01 0.01 0.02 0.03 0.01 0.01 0.02 0.03 0.01 10 Reheat Treatment Metallurgical Structure 7.1 For Grades D, E, F, G, H, I, J, and K forgings, one microscopy test shall be made from each size classification in each heat represented in each heat treatment lot The entire specimen shall show a uniform, heat-treated grain size of No or finer measured in accordance with Test Methods E 112 7.2 For grades specified in 7.1, a specimen for the microscopical test shall be cut from the large undistorted portion of the tension test specimen in such a way as will give a face transverse to the axis of the forging 10.1 If the results of the mechanical tests of any test lot not conform to the requirements specified, the manufacturer may retreat such lot, but not more than three additional times, and retests shall be made in accordance with Sections and 7, and shall meet the requirements for the grade of forgings involved 11 Inspection 11.1 Inspection of the material shall be made as agreed upon by the purchaser and manufacturer as part of the purchase contract Workmanship, Finish, and Appearance 8.1 The forgings shall conform to the sizes and shapes specified by the purchaser When centered, standard 60-deg centers with clearance drilled for lathe center points shall be used 8.2 The forgings shall be free of injurious imperfections and shall have a workmanlike finish 12 Rejection and Rehearing 12.1 Rejection: 12.1.1 Any rejection based on tests made in accordance with 5.3 shall be reported to the manufacturer within working days from the receipt of samples by the purchaser 12.1.2 Material that shows injurious imperfections subsequent to its acceptance at the manufacturer’s works will be rejected, and the manufacturer shall be notified 12.2 Rehearing—Samples tested in accordance with this specification that represent rejected material, shall be held for a period of 14 days from the date of notification In case of Number of Tests and Retests 9.1 If the results of the mechanical tests of any test lot not conform to the requirements specified because a flaw developed in the test specimen during testing, a retest shall be allowed if the defect is not caused by ruptures, cracks, or flakes in the steel A 730 – 93 (1999) TABLE Tensile Requirements Size Grade Bored Wall ThicknessA Solid Diameter or Thickness Over Not Over Over Tensile Strength, Elongation in in or Reduction Yield Point or Yield 50 mm, of Area, Strength, min, % min, % Not Over in mm in mm in mm in mm psi MPa psi MPa C (Annealed, normalized, or normalized and tempered)B 203 14 203 356 75 000 75 000 515 515 37 500C 37 500C 260 260 20 19 33 31 D (Annealed, normalized, or normalized and tempered)B 203 14 203 356 80 000 80 000 550 550 40 000C 40 000C 275 275 22 21 35 33 E (Normalized and tempered) 203 14 203 356 85 000 83 000 585 570 44 000C 43 000C 305 295 25 23 40 37 F (Double normalized and tempered) 12 203 305 12 14 203 305 356 102 102 152 88 000 86 000 84 000 605 595 580 50 000C 48 000C 46 000C 345 330 315 22 21 20 37 35 33 G (Quenched and tempered) 102 178 10 102 178 254 31⁄2 51 89 127 31⁄2 51 89 127 203 90 85 85 82 000 000 000 500 620 585 585 565 55 50 50 48 000D 000D 000D 000D 380 345 345 330 20 20 19 19 39 39 37 36 H (Normalized, quenched and tempered) 178 10 178 254 102 102 203 115 000 105 000 100 000 795 725 690 75 000D 65 000D 60 000D 515 450 415 16 18 18 35 35 35 I (Normalized and tempered) 203 20 203 508 102 102 203 80 000 80 000 550 550 55 000C 55 000C 380 380 28 28 60 55 J (Normalized and tempered) 13 127 229 330 13 20 127 229 330 508 21⁄2 41⁄2 61⁄2 64 114 165 21⁄2 41⁄2 61⁄2 64 114 165 203 90 90 90 88 000 000 000 000 620 620 620 605 60 60 58 56 000C 000C 000C 000C 415 415 400 385 24 22 21 20 48 44 42 40 K (Normalized and tempered) 13 127 229 330 13 20 127 229 330 508 21⁄2 41⁄2 61⁄2 64 114 165 21⁄2 41⁄2 61⁄2 64 114 165 203 95 95 93 91 000 000 000 000 655 655 640 625 72 70 67 65 000D 000D 000D 000D 495 485 460 450 23 22 22 21 55 53 50 48 L (Normalized, quenched, and tempered) 178 10 178 254 31⁄2 89 127 31⁄2 89 127 203 95 000 90 000 85 000 655 620 585 70 000D 65 000D 60 000D 485 450 415 23 20 20 54 50 50 M (Normalized, quenched, and tempered) 178 10 178 254 31⁄2 89 127 31⁄2 89 127 203 105 000 100 000 95 000 725 690 655 80 000D 75 000D 70 000D 550 515 485 20 19 19 50 50 50 N (Normalized, quenched, and tempered) 102 178 10 102 178 254 31⁄2 51 89 31⁄2 51 89 127 125 000 115 000 110 000 860 795 760 105 000D 95 000D 85 000D 725 655 585 16 16 16 50 45 45 A Where no figures are shown in the bored wall thickness column, it is understood that the size classification is determined by the outside diameter, whether the forging is bored or not B Alternative treatments specified are optional with the manufacturer C Yield point, see 6.4.1 D Yield strength, see 6.4.2 dissatisfaction with the results of the tests, the manufacturer may request a rehearing within that time 14 Product Marking 14.1 Identification marks shall be legibly stamped on each forging and each test specimen The purchaser may indicate the location of such identification marks 14.2 After the material has been inspected, the inspector shall stamp each accepted forging with his private mark 13 Certification 13.1 Upon request of the purchaser in the contract or order, a manufacturer’s certification that the material was manufactured and tested in accordance with this specification, together with a report of the test results, shall be furnished at the time of shipment A 730 – 93 (1999) 14.3 In addition to the above required markings, bar code tags may be applied to the forgings If these tags are applied, it is recommended that Bar Code 39 be used The size and location of the tags, as well as the information to be included, shall be agreed upon by the purchaser and the manufacturer 15 Keywords 15.1 alloy steel forgings; carbon steel forgings; rail applications SUPPLEMENTARY REQUIREMENTS One or more of the following supplementary requirements shall apply only when specified by the purchaser in the inquiry, contract, or order Details shall be agreed upon by the manufacturer and the purchaser S1 Chemical Composition S1.1 The purchaser may specify on Grades A through H that the residual alloy elements, not intentionally added, shall not exceed 0.25 % nickel, 0.20 % chromium, and 0.06 % molybdenum S1.2 The purchaser may specify on Grades I through N that the residual alloy elements, not intentionally added, shall not exceed 0.35 % copper, 0.25 % nickel, 0.20 % chromium, and 0.06 % molybdenum be split longitudinally The transverse and longitudinal faces shall be etched for macroscopic examination When macroetch testing of forgings is required, reference shall be made to the latest issue of Method E 381 S2 Turning S2.1 The purchaser may specify a preliminary rough machining prior to the heat treating operation S5.1 Any testing Sections and shall be a matter of agreement between the manufacturer and the purchaser S5.2 The purchaser may specify mechanical tests of Grades A and B forgings If mechanical property tests not conform to the requirements agreed upon, the manufacturer may anneal or normalize the lot involved, but not more than three times S4 Boring S4.1 Boring, as described in 4.5, may be specified S5 Additional Tests S3 Macroscopic Tests S3.1 The prolongation from the largest forging in each heat shall be sawed normal to the axis of the forging and shall then ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of 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 and if not revised, either reapproved or 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