Analysis and Control of Brittle Fracture of Fine Carbon Steel Strip
In the process of making high hardness saw blades with 65Mn hot-rolled steel strip as the base material,the sudden brittle fracture occurred during the shearing and rewinding of the steel strip.After reasonable sampling,spectral composition analysis,microstructure observation and Brinell hardness detection were used to analyze the failure causes.The results show that the composition,grain size and tensile properties of the failed steel strip meet the standard requirements.The grain size is coarse,the grain size is about grade 6,and the pearlite structure is the main microstructure but the pearlite is surrounded by mesh ferrite,the grain boundary is weakened,and the local mechanical properties are deteriorated.This kind of phenomenon can be significantly improved by taking hot rolled steel strip which is not out of storage or reproduced,and then delivering it after sufficient cooling.For the steel strip that has not been completely slow cooled out of the warehouse,the annealing can be used to improve the microstructure and avoid the broken strip.Hot-rolled steel strip is pre-annealed before cold rolling to reduce the hardness of the base material,and then cold rolling is carried out to reduce the deformation resistance of the steel strip,effectively improve the rolling speed,and significantly improve the production efficiency and performance stability.
万方数据
维普
