1、Standard Method of Test for Mechanical Testing of Steel Products AASHTO Designation: T 244-141ASTM Designation: A 370-12a American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4f T 244-1 AASHTO Standard Method of Test fo
2、r Mechanical Testing of Steel Products AASHTO Designation: T 244-141ASTM Designation: A 370-12a 1. SCOPE 1.1. These test methods cover procedures and definitions for the mechanical testing of steel, stainless steels, and related alloys. The various mechanical tests herein described are used to deter
3、mine properties required in the product specifications. Variations in testing methods are to be avoided and standard methods of testing are to be followed to obtain reproducible and comparable results. In those cases in which the testing requirements for certain products are unique or at variance wi
4、th these general procedures, the product specification testing requirements shall control. 1.2. The following mechanical tests are described: Sections Tension 6 to 14 Bend 15 Hardness 16 Brinell 17 Rockwell 18 Portable 19 Impact 20 to 29 Keywords 30 1.3. Annexes covering details peculiar to certain
5、products are appended to these test methods as follows: Bar products Annex A1 Tubular products Annex A2 Fasteners Annex A3 Round wire products Annex A4 Significance of notched-bar impact testing Annex A5 Converting percentage elongation of round specimens to equivalents for flat specimens Annex A6 T
6、esting multiwire strand Annex A7 Rounding of test data Annex A8 Methods for testing steel reinforcing bars Annex A9 Procedure for use and control of heat-cycle simulation Annex A10 1.4. The values stated in SI (MPa) units are to be regarded as the standard. 2014 by the American Association of State
7、Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f T 244-2 AASHTO 1.5. When this document is referenced in a metric product specification, the yield and tensile values may be determined in inch-pound (ksi) units then converted into SI (MPa) u
8、nits. The elongation determined in inch-pound gauge lengths of 2 or 8 in. may be reported in SI unit gauge lengths of 50 or 200 mm, respectively, as applicable. Conversely, when this document is referenced in an inch-pound product specification, the yield and tensile values may be determined in SI u
9、nits, and then converted into inch-pound units. The elongation determined in SI unit gauge lengths of 50 or 200 mm may be reported in inch-pound gauge lengths of 2 or 8 in., respectively, as applicable. 1.6. Attention is directed to R 18 when there may be a need for information on criteria for evalu
10、ation of testing laboratories. 1.7. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitati
11、ons prior to use. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standard: R 18, Establishing and Implementing a Quality Management System for Construction Materials Testing Laboratories 2.2. ASTM Standards: A 623, Standard Specification for Tin Mill Products, General Requirements A 623M, Standard Specificatio
12、n for Tin Mill Products, General Requirements Metric A 833, Standard Practice for Indentation Hardness of Metallic Materials by Comparison Hardness Testers E 4, Standard Practices for Force Verification of Testing Machines E 6, Standard Terminology Relating to Methods of Mechanical Testing E 8/E 8M,
13、 Standard Test Methods for Tension Testing of Metallic Materials E 10, Standard Test Method for Brinell Hardness of Metallic Materials E 18, Standard Test Methods for Rockwell Hardness of Metallic Materials E 23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials E 29, Standa
14、rd Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications E 83, Standard Practice for Verification and Classification of Extensometer Systems E 110, Standard Test Method for Indentation Hardness of Metallic Materials by Portable Hardness Testers E 190, Standa
15、rd Test Method for Guided Bend Test for Ductility of Welds E 290, Standard Test Methods for Bend Testing of Material for Ductility 2.3. ASME Code: ASME Boiler and Pressure Vessel Code, Section VIII, Division I, Part UG-84.23. SIGNIFICANCE AND USE 3.1. The primary use of these test methods is to dete
16、rmine the specified mechanical properties of steel, stainless steel, and related alloy products for the evaluation of conformance of such products to a material specification as designated by a purchaser in a purchase order or contract. 2014 by the American Association of State Highway and Transport
17、ation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f T 244-3 AASHTO 3.1.1. The material condition at the time of testing, sampling frequency, specimen location and orientation, reporting requirements, and other parameters are contained in the pertinent material spe
18、cification or in a General Requirement Specification for the particular product form. 3.1.2. Some material specifications require the use of additional test methods not described herein; in such cases, the required test method is described in the material specification or by reference to another app
19、ropriate test method standard. 3.2. These test methods are also suitable to be used for testing steel, stainless steel and related alloy materials for other purposes, such as incoming material acceptance testing by the purchaser or evaluation of components after service exposure. 4. GENERAL PRECAUTI
20、ONS 4.1. Certain methods of fabrication, such as bending, forming, and welding, or operations involving heating, may affect the properties of the material under test. Therefore, the product specifications cover the stage of manufacture at which mechanical testing is to be performed. The properties s
21、hown by testing prior to fabrication may not necessarily be representative of the product after it has been completely fabricated. 4.2. Improperly machined specimens should be discarded and other specimens substituted. 4.3. Flaws in the specimen may also affect results. If any test specimen develops
22、 flaws, the retest provision of the applicable product specification shall govern. 4.4. If any test specimen fails because of mechanical reasons such as failure of testing equipment or improper specimen preparation, it may be discarded and another specimen taken. 5. ORIENTATION OF TEST SPECIMENS 5.1
23、. The terms “longitudinal test” and “transverse test” are used only in material specifications for wrought products and are not applicable to castings. When such reference is made to a test coupon or test specimen, the following definitions apply: 5.1.1. Longitudinal Test, unless specifically define
24、d otherwise, signifies that the lengthwise axis of the specimen is parallel to the direction of the greatest extension of the steel during rolling or forging. The stress applied to a longitudinal tension test specimen is in the direction of the greatest extension, and the axis of the fold of a longi
25、tudinal bend test specimen is at right angles to the direction of greatest extension (Figures 1, 2(a), and 2(b). 5.1.2. Transverse Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is at right angles to the direction of the greatest extension of the stee
26、l during rolling or forging. The stress applied to a transverse tension test specimen is at right angles to the greatest extension, and the axis of the fold of a transverse bend test specimen is parallel to the greatest extension (Figure 1). 2014 by the American Association of State Highway and Tran
27、sportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f T 244-4 AASHTO Figure 1The Relation of Test Coupons and Test Specimens to Rolling Direction or Extension (Applicable to General Wrought Products) Figure 2Locations of Longitudinal Tension Test Specimens in R
28、ings Cut from Tubular Products Longitudinal SpecimenLongitudinal Flat Tension TestLongitudinal Round Tension TestLongitudinalBend TestLongitudinalImpact TestIndicates Rolling Directionor ExtensionTransverse SpecimenTransverse FlatTension TestTransverseBend TestTransverseImpact TestProlongationProlon
29、gationProlongationProlongationProlongationProlongationProlongationTangentialTestTangential TestTangential TestTangential TestTangentialTestTangentialTest(d) Ring Forgings(c) Disk Forgings(b) Hollow Forgings(a) Shafts and RotorsRadial TestLongitudinal TestLongitudinal Test 2014 by the American Associ
30、ation of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f T 244-5 AASHTO 5.2. The terms “radial test” and “tangential test” are used in material specifications for some wrought circular products and are not applicable to castings. Whe
31、n such reference is made to a test coupon or test specimen, the following definitions apply: 5.2.1. Radial Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is perpendicular to the axis of the product and coincident with one of the radii of a circle draw
32、n with a point on the axis of the product as a center (Figure 2(a). 5.2.2. Tangential Test, unless specifically defined otherwise, signifies that the lengthwise axis of the specimen is perpendicular to a plane containing the axis of the product and tangent to a circle drawn with a point on the axis
33、of the product as a center (Figures 2(a), 2(b), 2(c), and 2(d). TENSION TEST 6. DESCRIPTION 6.1. The tension test related to the mechanical testing of steel products subjects a machined or full-section specimen of the material under examination to a measured load sufficient to cause rupture. The res
34、ulting properties sought are defined in ASTM E 6. 6.2. In general, the testing equipment and methods are given in ASTM E 8/E 8M. However, there are certain exceptions to ASTM E 8/E 8M practices in the testing of steel, and they are covered in these test methods. 7. TERMINOLOGY 7.1. For definitions o
35、f terms pertaining to tension testing, including tensile strength, yield point, yield strength, elongation, and reduction of area, reference should be made to ASTM E 6. 8. TESTING APPARATUS AND OPERATIONS 8.1. Loading SystemsThere are two general types of loading systems, mechanical (screw power) an
36、d hydraulic. These differ chiefly in the variability of the rate of load application. The older screw power machines are limited to a small number of fixed free-running crosshead speeds. Some modern screw power machines and all hydraulic machines permit stepless variation throughout the range of spe
37、eds. 8.2. The tension testing machine shall be maintained in good operating condition, used only in the proper loading range, and calibrated periodically in accordance with the latest revision to ASTM E 4. Note 1Many machines are equipped with stressstrain recorders for autographic plotting of stres
38、sstrain curves. It should be noted that some recorders have a load measuring component entirely separate from the load indicator of the testing machine. Such recorders are calibrated separately. 8.3. LoadingIt is the function of the gripping or holding device of the testing machine to transmit the l
39、oad from the heads of the machine to the specimen under test. The essential requirement is that the load shall be transmitted axially. This implies that the centers of the action of the grips shall be in alignment, insofar as practicable, with the axis of the specimen at the beginning and during the
40、 test, and that bending or twisting be held to a minimum. For specimens with a reduced section, gripping of the specimen shall be restricted to the grip section. In the case of certain sections tested in full-size, nonaxial loading is unavoidable and in such cases shall be permissible. 2014 by the A
41、merican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4f T 244-6 AASHTO 8.4. Speed of TestingThe speed of testing shall not be greater than that at which load and strain readings can be made accurately. In production te
42、sting, speed of testing is commonly expressed (1) in terms of free-running crosshead speed (rate of movement of the crosshead of the testing machine when not under load), or (2) in terms of rate of separation of the two heads of the testing machine under load, or (3) in terms of rate of stressing th
43、e specimen, or (4) in terms of rate of straining the specimen. The following limitations on the speed of testing are recommended as adequate for most steel products: Note 2Tension tests using closed-loop machines (with feedback control of rate) should not be performed using load control, as this mod
44、e of testing will result in acceleration of the crosshead upon yielding and elevation of the measured yield strength. 8.4.1. Any convenient speed of testing may be used up to one-half the specified yield point or yield strength. When this point is reached, the free-running rate of separation of the
45、crossheads shall be adjusted so as not to exceed 0.063 mm per minute per millimeter (1/16in. per minute per inch) of reduced section, or the distance between the grips for test specimens not having reduced sections. This speed shall be maintained through the yield point or yield strength. In determi
46、ning the tensile strength, the free-running rate of separation of the heads shall not exceed 0.5 mm per minute per millimeter (1/2in. per minute per inch) of reduced section, or the distance between the grips for test specimens not having reduced sections. In any event, the minimum speed of testing
47、shall not be less than 1/10the specified maximum rates for determining yield point or yield strength and tensile strength. 8.4.2. It shall be permissible to set the speed of the testing machine by adjusting the free-running crosshead speed to the above specified values, inasmuch as the rate of separ
48、ation of heads under load at these machine settings is less than the specified values of free-running crosshead speed. 8.4.3. As an alternative, if the machine is equipped with a device to indicate the rate of loading, the speed of the machine from half the specified yield point or yield strength th
49、rough the yield point or yield strength may be adjusted so that the rate of stressing does not exceed 690 MPa (100,000 psi)/min. However, the minimum rate of stressing shall not be less than 70 MPa (10,000 psi)/min. 9. TEST SPECIMEN PARAMETERS 9.1. SelectionTest coupons shall be selected in accordance with the applicable product specifications. 9.1.1. Wrought SteelsWrought steel products are usually tested in the longitudinal direction, but in some cases, where size permits and the service justifies it, testing is in the transverse, radi
