1.1本规范涵盖多孔金属套筒、法兰、止推轴承和球形铁基轴承，这些轴承由使用粉末冶金（PM）技术的混合金属粉末制成，然后浸渍油以提供运行润滑。 1.2包括专门为制造这些自润滑轴承而开发和标准化的含铁粉末冶金材料的化学、物理和机械要求规范。 1.3本规范随附于规范B 438/B 438M 这涵盖了青铜基粉末冶金（PM）轴承（油浸）的要求。 1.4铁基轴承的典型应用见附录X1。 1.5商用轴承尺寸公差数据见附录X2，而有关PM轴承安装和运行参数的工程信息见附录X3。 有关自润滑轴承的其他有用信息，请参阅MPIF标准35（轴承）和技术文献。 1.6除g/cm 3. 单位是行业标准，以英寸-磅单位表示的数值视为标准。以英寸-磅为单位的数值应视为标准值。本标准不包括其他计量单位。 1.7 以下安全隐患警告仅适用于本规范中描述的测试方法。本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。

1.1 This specification covers porous metallic sleeve, flange, thrust, and spherical iron-base bearings that are produced from mixed metal powder utilizing powder metallurgy (PM) technology and then impregnated with oil to supply operating lubrication. 1.2 Included are the specifications for the chemical, physical, and mechanical requirements of those ferrous PM materials that have been developed and standardized specifically for use in the manufacture of these self-lubricating bearings. 1.3 This specification accompanies Specification B 438/B 438M that covers the requirements for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated). 1.4 Typical applications for iron-base bearings are discussed in Appendix X1. 1.5 Commercial bearing dimensional tolerance data are shown in Appendix X2, while engineering information regarding installation and operating parameters of PM bearings is included in Appendix X3. Additional useful information on self-lubricating bearings can be found in MPIF Standard 35 (Bearings) and the technical literature. 1.6 With the exception of density values for which the g/cm 3 unit is the industry standard, the values stated in inch-pound units are to be regarded as standard. The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 The following safety hazards caveat pertains only to the test methods described in this specification. 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 limitations prior to use.