What is the situation when cracks are found on the edge of the weld after stainless steel welding?

1. Hot cracks
Hot cracks are cracks generated in the high temperature stage of the welding cooling process, mainly in the weld metal. It also exists in small amounts near the seam, and is divided into crystallization (solidification) cracks, liquefaction cracks and polygonization cracks. Among them, crystal cracks are common cracks, mainly occurring in carbon steel welding with many impurity elements.
2. Reheating cracks
During the stress relief treatment of thick plate welding structures, when there are different degrees of stress concentration in the coarse grain area of ​​the heat affected zone, the additional deformation caused by stress relaxation is greater than the creep plasticity of this part, and reheating cracks are generated; the generation temperature is usually 550℃～650℃;
The location of cracks in 316l stainless steel water pipes is usually located in the coarse grain area of ​​the heat affected zone; the crack morphology is cracking along the grain boundary.
3. Cold cracks
The cracks generated when the welded joint is cooled to a lower temperature (below M. temperature for steel) are called cold cracks. Cold cracks may appear immediately after welding, or they may appear after a period of time (several hours, days or even longer). This type of crack is also called delayed crack. It is a common form of cold cracks and is more dangerous.
4. Stress corrosion cracks
Some welded structures (such as containers and pipelines) produce delayed cracking under the combined action of corrosive media and stress; it can occur at any temperature; the location of the crack is usually located in the weld and heat-affected zone; the crack morphology is intergranular or transgranular.