Reasons for bending and cracking of cold-rolled galvanized strip steel

After the bending test of galvanized strip steel in a certain cold rolling plant, the samples often cracked. The causes of cracking in bent specimens of different steel grades were analyzed using methods such as chemical composition analysis, mechanical property testing, and metallographic examination. The results show that the cracking reason of Q195C steel bending specimen was due to the high grade of A-series free cementite, Q355B steel bending specimen was due to severe banded structure, and Q420XG steel bending specimen was due to incomplete annealing of the structure. methods such as component optimization, controlled cooling after hot rolling, and cold rolling annealing process adjustment could improve the bending performance of materials.