Mechanism and Control of Stress Concentration Induced Bending and Cracking of Low Alloy Steel Strip
ZHANG Ruiqi
SUN Qian
TIAN Qi
LIU Zongshun
Abstract：To address the cracking issue during the bending process of 355 MPa grade steel strip,multiple technical methods including metallographic structure observation,scanning electron microscopy characterization,and mechanical property testing were employed to systematically investigate the core causes of the cracking failure.The test results indicated that the main structure of the steel strip was pearlite and ferrite,with a small amount of bainite,and the grain size was approximately grade 10 with uniform distribution.The mechanical property indicators met the standards but were on the high side.After the steel strip was slit,burrs were found on the edges.If the bending radius was too small during bending,it would cause significant stress concentration on the edges,and the outer layer metal deformation would exceed the plastic limit,which was the main cause of cracking.In addition,the steel strip surface was covered with iron oxide scale,and there was slight pearlite segregation in the core,further increasing the cracking sensitivity.In response to the causes,it is recommended to strictly control the segregation of the cast billet,optimize the surface cleaning process,and improve the edge cutting accuracy.
Keywords：355 MPa grade steel stripbendingbainitestress concentrationcracking sensitivity
Publication Date：2025-08-20
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：4( 9-12 )