大型的铸、锻、焊件,在制造和热处理过程中,往往产生很大的残余应力,它会降低构件的强度。同时它会缓慢地自然释放,对精加工后的零件产生变形,失去尺寸精度。由于产生残余应力的原因极为复杂,分布极不均匀,用计算方法求解目前还是很困难的,往往需要适合现场实测的测试方法来解决。测试方法可归纳为二类:物理的和机械的。常见的物理方法如x线衍射法、超声法、磁性法,是属无损的;常见的机械方法如盲孔法、逐次去层法、切割法,都用电阻应变计作敏感元件,是属有损的。其中以小直径盲孔法对零部件损伤较小,不影响继续使用,设备简单,测量较可靠, Large cast, forged, welded parts, in the manufacturing and heat treatment process, often have a lot of residual stress, it will reduce the strength of components. At the same time it will be slow and natural release, deformation of the finished parts, loss of dimensional accuracy. As the causes of residual stress are extremely complicated and the distribution is very uneven, it is still very difficult to solve by calculation method, and often it is necessary to solve the test method which is suitable for field measurement. Test methods can be grouped into two categories: physical and mechanical. Common physical methods such as x-ray diffraction, ultrasonic method, magnetic method, is a non-destructive; common mechanical methods such as blind hole method, successive delamination method, cutting method, are used as a sensitive element resistance strain gauge, Damaged. One of the small diameter blind hole method of damage to small parts, does not affect the continued use of equipment is simple, reliable measurement,