Why do steel structures have hot cracks?

Hot cracks may occur in steel structures during welding. This is due to the local heating of the weld area during the welding process. When the temperature reaches a certain temperature, the steel will undergo thermal deformation, and the internal stress will be generated during the thermal deformation process, which will lead to the deformation or crack of the structure. In addition, thermal deformation can also cause structural deformation, residual stress after deformation, material defects and quality problems.

Specifically, the main causes of hot cracks in steel structures are as follows:

one

Structural problems: The welded steel may cause thermal stress concentration due to the uneven structure, such as oversized grains, inclusion and other defects, which may lead to the formation of thermal cracks.

two

Temperature problem: too high or too low temperature during welding will affect the structure of steel. Too high temperature will easily produce excessive heat affected zone, leading to hot cracks, and too low temperature will affect the formability of steel.

three

Improper selection of welding method: different welding methods correspond to different welding conditions and requirements. If the selected welding method does not match the composition, thickness and shape of steel, it may lead to thermal cracks in the structure.

four

In order to avoid the occurrence of hot cracks in steel structures, it is necessary to strictly control the temperature, time and method of welding, and at the same time, it is necessary to fully detect and evaluate the structure of materials, and try to avoid the occurrence of overly complex structures in steel during design, so as to reduce the generation of thermal stress. At the same time, in actual production, it is also necessary to take appropriate measures such as preheating, welding parameters and post-heat treatment to minimize the occurrence of hot cracks.