1.1 本规程涵盖了使用交流电作为电源对钢锻件进行磁粉检测的程序。该程序将产生一致的结果，可作为验收标准的依据。本规程不包含验收极限或建议的质量水平。 1.2 任何磁化方法的电源只能使用50–60周的交流电。 1.3 当在锻件中寻找亚表面迹象时，应按照惯例进行直流磁化 A275/A275M 应使用。 1.4 以英寸为单位的数值- 磅单位或国际单位应单独视为标准。在文本中，国际单位显示在括号中。每个系统中规定的值不一定是精确的等价物；因此，为确保符合本标准，每个系统应独立使用，且两个系统的值不得组合。除非订单规定了适用的“M”规格名称[国际单位制]，否则应使用英寸-磅单位。 1.5 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、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 对于铁磁性材料，磁粉检测广泛用于检测表面和近表面缺陷，如裂纹、搭接、接缝和线性取向的非金属夹杂物。此类检查作为强制性要求包含在一些锻造标准中，如规范 A508/A508M 和 A963/A963M . 5.2 使用交流电作为磁粉检测的电源对检测次表面缺陷施加了很大的限制，因此该程序基本上仅限于发现对表面开放的缺陷。因此，需要注意的是，在进行磁粉检测之前，需要使部件处于精加工状态。 5.3 部件中存在残余磁场可能是不可取的，使用交流电源进行磁粉检测的优点是可以轻松达到可接受的退磁水平。

1.1 This practice covers a procedure for the magnetic particle examination of steel forgings using alternating current as the power source. The procedure will produce consistent results upon which acceptance standards can be based. This practice does not contain acceptance limits or recommended quality levels. 1.2 Only alternating 50–60 cycle current shall be used as the electric power source for any of the magnetizing methods. 1.3 When subsurface indications are sought in forgings, then dc magnetization in accordance with Practice A275/A275M should be used. 1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Unless the order specifies the applicable “M” specification designation [SI units], the inch-pound units shall be used. 1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 For ferromagnetic materials, magnetic particle examination is widely specified for the detection of surface and near-surface flaws such as cracks, laps, seams, and linearly oriented nonmetallic inclusions. Such examinations are included as mandatory requirements in some forging standards such as Specifications A508/A508M and A963/A963M . 5.2 Use of alternating current as the power source for magnetic particle examination imposes a significant restriction on the detection of subsurface indications, so that the procedure is essentially limited to the finding of flaws that are open to the surface. Attention therefore is drawn to the need to have the component in the finish-machined condition before conducting the magnetic particle examination. 5.3 The presence of residual magnetic fields in a component may be undesirable, and an advantage of the use of an ac power source for magnetic particle examination is that an acceptable level of demagnetization can be readily achieved.