The phenomenon of welding cracks

Phenomenon of welding cracks

In the weld or near-weld area, due to the influence of welding, the atomic bonding of the material is destroyed, and the gap formed by the new interface is called welding crack, which has the characteristics of sharp notch and large aspect ratio.

According to the temperature and time when it is generated, cracks can be divided into: hot cracks, cold cracks, stress corrosion cracks and layered tearing. In welding production, there are many places where cracks are generated. Some cracks appear on the surface of the weld and can be observed with the naked eye; some are hidden inside the weld and can only be found through inspection; some are generated on the weld; some are generated in the heat-affected zone. It is worth noting that cracks are sometimes generated during the welding process, and sometimes appear after the weldment is placed or operated for a period of time after welding. The latter is called delayed cracks, which are more harmful. The occurrence location and morphology of common cracks are shown in the figure below.