AAR_M201-2000美国铁路协会铸钢件标准

Couplers and Freight Car Draft Components
M-201
STEEL CASTINGS
Specification
M-201-00
Adopted: 1923; Revised: 1984, 1993, 2000
1.0SCOPE
These specifications cover carbon and alloy steel castings for locomotive and car equipment and for miscellaneous use graded as A, B, B+, C, D, and E. AAR Specification M-201 provides for all cast-ings unless another AAR specification for a particular product provides for a variation.
2.0BASIS OF PURCHASE
Grade A castings shall be furnished unannealed, annealed, or normalized unless otherwise speci-fied by the purchaser. Grades B and B+ castings shall be furnished normalized or normalized and tempered. Grade C castings shall be furnished normalized and tempered or quenched and tem-pered. Grades D and E castings shall be furnished quenched and tempered.
2.1At the purchaser’s request, a certification will be made the basis of acceptance. The certifica-tion shall include a statement that the material has been manufactured, sampled, tested, and inspected in accordance with, and meets the requirements of, all applicable provisions of these specifications. Each certification furnished shall be signed by an authorized agent of the supplier or manufacturer.
3.0RECORDS
The manufacturer shall maintain for 15 years records of the mechanical and chemical test reports covering the heats representing the purchased castings. These records will be made available to the purchaser upon request.
MANUFACTURE
4.0PROCESS
The steel may be made by one or more of the following processes: Open hearth, electric furnace, crucible, converter, or basic oxygen.
5.0HEAT TREATMENT
Castings shall be cleaned sufficiently to respond to heat treatment. Internal cavities shall not be blocked by molding material. They shall then be treated according to the following procedure appropriate to the requirements of paragraph 2.0.
5.1Heat Treatment
5.1.1After pouring, castings shall be allowed to cool to a temperature below 1,000 °F (538 °C) prior to heat treatment at a rate that will not be injurious to the castings.
5.1.2Full Annealing
The casting shall be heated to the proper temperature above the transformation range for the required time to achieve complete austenization and to refine the grain structure. The casting shall then be allowed to cool slowly in the furnace. Unless otherwise required by the purchaser, the manufacturer has the option of normalizing instead of full annealing, where full annealing is spec-ified.
5.1.3Normalized steel castings shall be processed in the following order:
5.1.3.1Heat to the proper uniform temperature above the transformation range and hold for the proper time to achieve complete austenization and to refine the grain structure.
5.1.3.2Withdraw from the furnace and cool in still air until temperature is below 700 °F (371 °C).
5.1.3.3At the manufacturer’s option, Grades B and Bϩ castings specified as normalized may receive a subsequent tempering.
5.1.4Normalized and tempered steel castings shall be processed in the following order:
5.1.4.1Heat to the proper uniform temperature above the transformation range and hold for the proper time to achieve complete austenization and to refine the grain structure.
5.1.4.2Withdraw from the furnace and cool in still air until castings in their entirety are at least 100 °F below tempering temperature.
5.1.4.3Temper by reheating to the proper uniform temperature below the transformation range, but not less than 600 °F and hold for the required time. Remove from the furnace and allow to cool at any desired rate.
5.1.5Quenched and tempered steel castings shall be processed in the following order:
5.1.5.1Heat to the proper uniform temperature above the transformation range and hold for the proper time to achieve complete austenization and to refine the grain structure.
5.1.5.2Withdraw from the furnace and while castings are above the transformation range, sub-ject to rapid cooling by suitable liquid medium to a temperature substantially below the transfor-mation range.
5.1.5.3Temper by reheating to the proper uniform temperature below the transformation range, but not less than 800 °F. Hold for the required time, remove from the furnace, and allow to cool at any desired rate. All castings prone to cracking after quenching shall be tempered as soon as nec-essary to prevent cracking, but in no case shall the time between quenching and tempering exceed 8 hours.
5.2Heat Treatment Documentation
These provisions apply only to truck frames, bolsters, coupler bodies, yokes, draft gears, or cushion units. The manufacturer is required to develop and document heat, treating standards that describe the processes, process control procedures, and record keeping requirements. These docu-ments are to be presented and reviewed as part of the Foundry Approval process and are intended to ensure that products are properly heat treated. Furnace temperatures for heat treatment shall be controlled by pyrometers having associated recording equipment that produce time-tempera-ture record charts that are identified by date and furnace number. A log sheet for each load of cast-ings heat treated should show all information pertinent to each heat treat load, including 1) type of product; 2) the prescribed heat treatment; 3) the serial numbers (if not available, the heat num-bers) of the castings on the load; 4) the identification number of the test coupon or coupons charged with the load; and 5) actual time of heat treatment. Alternate procedures will be considered, pro-vided a detailed proposal is submitted in writing to the AAR for approval. This submission must ensure that the intent of this specification is being complied with. Pyrometers shall be calibrated every three months. Records of time-temperature charts, furnace log sheets, and pyrometer cali-brations will be maintained for 3 years and made available to the purchaser upon request.
5.3Test Lugs
For all castings, at least two and not more than four test lugs shall be cast on all castings 150 lb and over and on such castings less than 150 lb as required by the purchaser. The location of the test lugs shall be such that when removed by the inspector, they shall indicate if the casting has been subjected to heat treatment. If inspection of the test lug indicates that the casting has not been heat treated, the casting will be heat treated. The standard test lug shall be 1in. high, 1in. wide, and 1/2 in. or 5/8 in. thick where it joins the casting.
Couplers and Freight Car Draft Components M-201
6.0CHEMICAL PROPERTIES AND TESTS
6.1Chemical Composition
The steel analysis shall not exceed the following:
6.1.1Grades A, B, and B+ Steel
For each reduction of 0.01% carbon below the maximum specified, an increase of 0.04% manganese above the maximum specified will be permitted, to a maximum of 1.2%.
6.1.2The content of elements other than those designated in paragraph 6.1 shall be selected by the manufacturer to obtain the physical properties specified.
6.2Hardenability
6.2.1Grades D and E Steel
Composition of steel, except for coupler locks, shall produce in the standard Jominy test the mini-mum hardness at 7/16 in. from the quenched end for the carbon composition as follows, based on the initial composition:
6.2.2Frequency of Test
Following satisfactory Jominy test results for 10 consecutive heats, the manufacturer shall con-duct one Jominy test at least once every month for Grades D and E steel.
6.2.3Hardenability Calculations
The Ideal Critical Diameter (DI) shall be calculated for each heat of quenched and tempered steel in accordance with ASTM Designation A255, Appendix III, latest revision. The calculated DI value shall be shown as information on the report of mechanical and chemical tests as defined as para-graph 3.0.
6.3Chemical Analyses
6.3.1Ladle Analysis
An analysis of test samples taken during the initial 25% of the castings poured from each ladle must be made by the manufacturer to determine the percentage of carbon, manganese, phospho-rus, sulfur, silicon, and intentional alloying elements. The result of this analysis shall be reported to the purchaser or purchaser’s representative upon request and shall conform to the require-ments of paragraph 6.1. If drillings are used, they must be taken at least 1/4 in. beneath the sur-face of the test ingot.
6.3.2End of Heat Analysis
For each heat of steel, a sample representing the last metal going into, or taken after the pouring of, the last acceptable casting must be used by the manufacturer to determine the percentage of manganese. The results of this analysis shall be reported to the purchaser or purchaser’s represen-tative upon request and shall conform to the requirements of paragraph 6.1. If drillings are used,
Grades A, B, & B+Grades C, D, & E Carbon, maximum percentage
0.320.32Manganese, maximum percentage
0.90 1.85Phosphorus, maximum percentage
0.040.04Sulfur, maximum percentage
0.040.04Silicon, maximum percentage 1.50 1.50
Percentage Carbon
Minimum Hardness, R c up to .25
0.25 to 0.30
0.31 to 0.32303335
they must be taken at least 1/4 in. beneath the surface of the test ingot. Records shall be main-tained for 2 years only.
6.4Check Analysis
An analysis may be made by the purchaser from the broken tension test specimen or from a cast-ing of each heat. The chemical composition thus determined shall conform to the requirements specified in paragraph 6.1. Drillings for analysis shall be taken not less than 1/4 in. beneath the surface and shall be taken in such a manner as not to impair the usefulness of a casting.7.0MECHANICAL PROPERTIES AND TESTS
7.1Tensile Test Specimen Coupons
7.1.1At the manufacturer’s option, coupons shall be either cast attached to the casting or the gating system or produced from keel blocks and prepared in accordance with ASTM Designation A370.
7.1.2The process used for the manufacture of keel blocks shall be representative of the manufacturer’s normal process methods.
7.1.3Each melt shall be tested for mechanical properties after heat treatment. The coupons from each melt shall be heat treated with castings of the same grade, in the same manner as the cast-ings they represent. Each heat treat furnace load shall include at least one test coupon of the same grade of steel and have its mechanical properties determined and recorded.
Batch process heat treat furnace load is defined as all the castings in the heat treat furnace of the same grade of steel. Continuous process heat treat furnace load is defined as all the castings of the same grade of steel that pass a given location in the furnace during the period of one heat treating cycle.
7.2Tension Test
7.2.1Test shall be conducted in accordance with Standard Methods and Definitions for Mechani-cal Testing of Steel Products , ASTM Standard A370, using 1/2-in. round (13 mm) 2-in. (50 mm)gauge length specimens as illustrated in that specification. Specimens are to be removed from cou-pons produced per paragraph 7.1.1.
7.2.2The steel used for the casting shall conform to the following minimum requirements.
7.2.3The manufacturer shall test specimens from melt heats and record results, excluding flawed specimens. One specimen per heat for each grade of steel shall be tested. If a test specimen shows a defect during machining or exhibits flaws before or after testing, it shall be discarded and another specimen substituted. Specimens to be removed from coupons produced per paragraph
7.1.1.
7.2.4If the percentage of elongation of any tension specimen is less than that specified, and any part of the fracture is more than 3/4 in. from the center of the gauge length as indicated by the gauge marks on the specimen before testing, a retest is allowed. Specimens to be removed from coupons produced per paragraph 7.1.1.
Grade A
Gr. B Gr. B+Gr. C Gr. D Gr. E Unannealed
Annealed or Normalized Tensile strength, ksi
6060708090105120Yield point, ksi
303038506085100Elongation in 2", %
22262424221714Reduction of area, %30383636453530
Couplers and Freight Car Draft Components M-201
7.2.5At the time of purchase, specimens may be cut from castings (excluding flawed specimens)and must have at least 80% of the tensile and yield properties established in paragraph 7.2.2.
7.2.6Results of testing must show compliance with the requirements of paragraph 7.2.2 prior to shipment of finished castings.
7.3Impact Test
7.3.1The steel shall possess impact properties determined by testing standard Charpy-V-Notch Type “A” specimens prepared as illustrated in Figure 11 in ASTM Standard A370. Specimens to be removed from coupons produced per paragraph 7.1.1. A test consists of determining the average energy absorbed from three impact specimens from the same heat. The results shall meet the fol-lowing minimum requirements at the stated temperatures:
7.3.2Impact tests shall be conducted in accordance with the Standard Methods and Definitions for Mechanical Testing of Steel Products , ASTM Standard A370.
7.3.3The manufacturer shall test specimens from melt heats and record results, including chem-istry of that heat, excluding flawed specimens. Frequency of these tests shall be one heat per week per grade of steel obtained during the pouring of the last 25% of heat. Specimens to be removed from coupons produced per paragraph 7.1.1.
7.3.4As a manufacturer’s alternative, impact properties may be determined by use of the Dynamic Tear Test (ASTM E604) or the Nil Ductility Transition Test (ASTM E208). Specimens to be removed from coupons produced per paragraph 7.1.1.
7.3.4.1The Dynamic Tear Test shall consist of determining the average energy absorbed from three specimens from the same heat, which shall be a minimum of 50 ft lb at the temperatures specified in the table in paragraph 7.3.4.3.
7.3.4.2The Nil Ductility test shall consist of testing two specimens at the temperatures specified in the table in paragraph 7.3.4.3. Both specimens shall exhibit “no-break” performance.
7.3.4.3Dynamic Tear and Nil Ductility Test Temperatures shall be:
7.3.4.4The record keeping requirements and test frequency are the same as specified in para-graph 7.3.3.
7.3.5 A check test may be made by purchaser from a casting at purchaser’s expense. Results of this testing shall conform to the minimum values specified in paragraph 7.3.4.
Cast Steel
Temperature (°F)Energy (ft lb)Grades B and B+
Grade C (NT)
Grade C (QT)
Grade D
Grade E +200–40–40–401515202020
Dynamic Tear and Nil Ductility Test Temperatures
Cast Steel Testing Temperature (°F)
Grades B and B+Grade C (NT)Grade C (QT)Grade D Grade E +60
+60
–60
–60–60
7.4Hardness
Cast steel components, except as provided for in product specifications, must be within a Brinell Hardness range as follows:
Testing to be done on a surface that has been ground to remove decarburization in accordance with ASTM A370.
8.0NUMBER OF TESTS, SMALL ORDERS
In case of small orders for castings weighing over 180 lb where the size of the order and the avail-able pattern and foundry equipment are such that not more than five castings can be cast in one heat, the physical properties, as required in paragraph 7.0, will be determined from an extra or spare test coupon cast with and attached to some other casting of the same heat.
9.0RE-HEAT TREATMENT
If the results of the physical test lot do not conform to the requirements specified, the manufac-turer may re-heat treat such lot not more than twice, and retests shall be as specified in paragraph 7.0.
WORKMANSHIP AND FINISH
10.0WORKMANSHIP
All castings shall conform to the dimensions on drawings furnished by the purchaser before manu-facture is started; or to the dimensions predicated by the pattern supplied by the purchaser, if no drawing has been provided.
11.0FINISH
The castings shall be free from injurious defects and shall be thoroughly cleaned when offered for inspection.
12.0WELD REPAIR OF DEFECTS
12.1Weld Repair of Defects
The entire defect must be removed prior to weld repair. The area to be welded must have the sides contoured to provide for the application of a sound weld. Maximum depth of repaired area must allow at least 1/8 in. sound metal remaining between the bottom of the weld groove and the oppo-site side of the casting wall in areas where welding cannot be accomplished from both sides of the casting wall. Where a defect continues through the casting wall and both sides of the wall are accessible for welding, the casting shall be welded from both sides using a double “V” or a “U” con-tour weld. Where defect continues through the casting and is inaccessible from both sides and unless prohibited by specific component specification, defect may be weld repaired by using a cop-per backup plate provided the surface is smooth and clean.
12.2Welders shall be qualified and use procedures under the welder qualification procedure con-tained in AWS 15.1, or equivalent, in the position welding is to be performed.
12.3Defects may be repaired by using a metal-electrode arc welding process that will result in sound weld deposit having, in the heat-treated condition, minimum mechanical properties equal to the requirements for the parent metal. Welding may be performed in either the non-heat-treated or heat-treated condition. Post-weld heat-treatment requirements are outlined in the product specification for the component involved.
Material Grade Identification
BHN Range Grade A
Grades B and B+
Grade C
Grade D
Grade E 108–160137–208179–241211–285241–311
Couplers and Freight Car Draft Components
M-201
12.4Grade A, B, B+, C, D, or E castings shall not be welded while the temperature of the casting is below 40 °F. Localized preheating is acceptable. If local preheating is performed, the casting shall be uniformly preheated to a temperature between 300 °F and 600 °F, and welding shall be accomplished while the casting is maintained at a temperature above 300 °F. The temperature shall not exceed 600 °F to avoid the possibility of warping.
12.5For Welding Grade A Steel Castings
If shielded metal arc process is used, the electrode shall be E6015, E6016, E6018, or equivalent.
12.6For Welding Grades B and B+ Steel Castings
If shielded metal arc process is used, the electrode shall be a low hydrogen coated type as follows: for Grade B—AWS/ASTM Class E7015, E7016, E7018, E8015, E8016, E8018, or equivalent may be used; for Grade B+—AWS/ASTM E8015, E8016, E8018, or equivalent may be used.
12.7For Welding Grade C Steel Castings
If shielded metal arc process is used, the electrode shall be a low hydrogen coated type, AWS/ASTM Class E9015, E9016, E9018, or equivalent. At the option of the manufacturer, an elec-trode of the AWS/ASTM Class E10015, E10016, E10018, or equivalent may be used for higher mechanical properties after heat treatment.
12.8For Welding Grade D Steel Castings
If shielded metal arc process is used, the electrode shall be a low hydrogen coated type AWS/ASTM E11015, E11016, E11018, or equivalent.
12.9For Welding Grade E Steel Castings
The welding materials used for the repair of defects in Grade E steel castings shall be AWS/ASTM Class electrode E12015, E12016, E12018, E13015, E13016, E13018, or equivalent.
13.0MARKING
When marking requirements are not covered by individual product specification, the manufac-turer’s identification mark, the pattern number and grade, and, when specified, the purchaser’s initials shall be legibly cast on all castings.
VARIATION IN WEIGHT
14.0VARIATION IN WEIGHT
When not covered by individual product specification, the weight agreed upon between the pur-chaser and the manufacturer shall not vary more than 5% above or 3% below the determined weight of the castings.
INSPECTION AND REJECTION
15.0INSPECTION
15.1The inspector representing the purchaser shall have free entry, at all times while the work on the contract of the purchaser is being performed, to all parts of the manufacturer’s works that concern the manufacture of the material ordered. The manufacturer shall afford the inspector, free of charge, all reasonable facilities and necessary assistance to satisfy the inspector that the mate-rial is being furnished in accordance with these specifications. Tests and inspection shall be made prior to shipment at the place of manufacture unless otherwise specified.
15.2The purchaser may make tests to govern the acceptance or rejection of the material in pur-chaser’s laboratory or elsewhere. Such tests shall be made at the expense of the purchaser.
15.3Rejection
Material represented by samples that fail to conform to the requirements of these specifications, or to individual product specification, will be rejected.
15.4Material that, subsequent to test and inspection at the foundry or elsewhere and its accep-tance, shows injurious defects will be rejected, and the manufacturer shall be notified.
15.5AAR Representation
In addition to the purchaser’s representation, an AAR official representative shall have free entry at all times to all parts of the manufacturer’s works that concern the manufacture, test, and inspection of materials for use in Interchange Service. This access is for the purpose of providing assurance that industry standards are being maintained. The manufacturer shall afford the AAR representative all reasonable facilities to ensure that materials are being furnished in accordance with these specifications.。