ISO 8642:2008规定了在最大工作温度大于425°C的情况下用于航空航天结构的MJ螺纹公制自锁螺母的试验方法。它描述了每次试验的试验装置和方法。 ISO 8642:2008适用于上述自锁螺母，前提是相关文件（尺寸标准、图纸、采购规范等）参考本国际标准。 可使用ISO 8642:2008规定以外的其他试验装置或试验方法，但如有争议，应以本国际标准规定的要求为准。 ISO 8642:2008应与ISO 8641一起使用。

ISO 8642:2008 specifies test methods for metric self-locking nuts with MJ threads intended for use in aerospace construction at maximum operating temperature greater than 425 °C. It describes the test device and the method for each test. ISO 8642:2008 applies to self-locking nuts as defined above, provided that the relevant documents (dimensional standard, drawing, procurement specification, etc.) refer to this International Standard. Other test devices or test methods than those specified in ISO 8642:2008 may be used, but, in the event of a dispute, the requirements laid down in this International Standard shall take precedence. ISO 8642:2008 shall be used in conjunction with ISO 8641.