钢淬透性的测定方法

[中文适用范围]： 本 SAE 标准规定了对浅层和中层硬化钢进行淬透性测试并记录结果的程序，但不适用于通常空气硬化的深度硬化钢。其中包括对中度和浅层硬化钢使用 25 毫米（1 英寸）标准淬透性端部淬火样品的程序，以及对直径小于 32 毫米（1-1/4 英寸）的棒材使用小尺寸方法的程序。 SAE J1975 中给出了测定渗碳钢表面淬透性的方法。在本文件中给出的条件之外的其他条件下进行的任何淬透性测试将不被视为标准，并将受到供应商和用户之间的协议的约束。每当进行检查测试时，所有相关实验室必须安排使用相同的替代程序，参考测试样品和硬度测试的研磨方法。 [外文原描述]： This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden. Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels and subsize method for bars less than 32 mm (1-1/4 in) in diameter. Methods for determining case hardenability of carburized steels are given in SAE J1975. Any hardenability test made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing. For routine testing of the hardenability of successive heats of steel required to have hardenability within certain limits, it is sufficient to designate hardenability simply in terms of distance from the quenched end to the point at which a certain hardness is obtained. This designation may also be adequate for comparing steels of different compositions to see whether they have similar hardenability. Hardenability limits for specifying steel in this manner are obtained by measuring the hardenability of a steel which has proved satisfactory for the use intended. The hardenability test may be used in this way as an empirical test. For new components where manufacturing experience is lacking, hardenability data may be effectively used to estimate the hardness profile provided by any given steel. Attendantly, the ability to predict hardenability from chemical composition has become increasingly important when comparing various steel grades or developing new steels for specific applications. One such procedure is described in Appendix A. Other hardenability prediction methods are available from the selected references in Section 2 . However, it should be emphasized that the use of any hardenability prediction procedure does not preclude the importance of conducting Jominy end-quench tests to determine the actual hardenability of any specific grade of steel. Hardenability data may be used to estimate hardnesses obtainable with any steel in new machine parts not yet in production and not similar to any parts on which production experience is available. Various hardenability application methods are described in the selected references, Section 2.1 , 23 to 25. It appears none of these methods are precise, but these are often useful for estimation purposes. Final correlation on actual parts is necessary.