Determination of mechanical properties of metal of welded joints by strength parameters in the stress concentration zones detected by the metal magnetic memory method

摘要

The magnetic memory of metal (MMM) is an aftereffect, which occurs in the form of metal residual magnetization in components and welded joints formed in the course of their fabrication and cooling in the weak magnetic field of the earth and in the form of irreversible change of components' magnetization in zones of stress concentration and damage under working loads (ISO 24497-1:2007(E)). Experience with carrying out comprehensive testing of welding specimens by the MMM method with subsequent stress concentration zones (SCZs) detection and determination of the mechanical properties by hardness characteristics is described. It is shown that the microhardness and consequent mechanical properties in the SCZs considerably exceed the average level of above characteristics.