Cause Analysis and Improvement of Inclined Crack in Low Alloy Steel Square Pipe after Welding
WANG Zhe
SUN Qian
HOU Guangda
ZHENG Li
LI Cheng
YANG Hui
Abstract：In view of the actual problem of oblique crack of Q355B low alloy hot rolled steel strip after bending square pipe welding,the 7.75 mm problem steel strip was selected as the research object.The chemical composition,mechanical properties,Brinell hardness,metallostructure and other inspection and analysis were carried out.The results show that all indexes of the base metal steel strip meet the standard requirements.The analysis shows that the cutting quality of longitudinal shear is not high,there are small cracks at the edge of shear,and the crack propagation caused by coil stress is the main reason for the crack after welding.In actual production,proper longitudinal scissors are selected and maintained regularly to avoid the influence of stress concentration defects such as tool rust and wear on the shear quality of steel strip edge.At the same time,according to the thickness and mechanical properties of steel strip,reasonable layout of shear plate,adjusting to a reasonable height and optimizing the shear process can effectively avoid the problem of post-welding cracks.
Keywords：Q355Bhot-rolled steel stripweldingcrackshear quality
Publication Date：2023-12-20
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：4( 48-50,53 )