Study On The Mechanism Of Rolling Edge Crack Of High Grade Silicon Steel

This paper is aiming at researching the edge crack problem of high grade silicon steel of cold rolling mill of a steel plant.Through field sampling analysis,rolling test sampling analysis,finite element simulation analysis and so on,the factors affecting the edge crack materials such as microstructure,rolling technology and shearing process have been determined when the high grade silicon steel is rolled at the cold tandem mill.The main points are as follows:The hardness of high grade silicon steel is analyzed through on-site sampling firstly.It is found that the hardness of the edge part is lower than that of other parts.One of the reasons for the edge crack is poor ability of the edge part to resist the deformation of the external force.Then the mechanical properties of silicon steel are tested.It is also found that the poor ductility of its edge part is one of the reasons of its edge crack.Metallographic analysis of cold rolled sheet is tested.It is also found that the existence of mixed crystal structure at the edge is one of the reasons for the edge crack.Through aging analysis,it is found that the increase of aging will lead to the decrease of ductility and the edge crack of silicon steel.The pickling test showed no hydrogen embrittlement of the silicon steel.It was found that the shear state of disc shear affected the edge crack.Finally,the rolling test of sampling silicon steel in the field was carried out.The fracture surface of silicon steel was analyzed by SEM and EDS.The fracture mechanism of silicon steel is cleavage fracture.This paper is based on the above experimental analysis.Simulation Model of Rolling is based on finite element Software MARC.The appropriate damage model is chosen to simulate the rolling process of silicon steel accurately.The influence of the rolling process parameters on the edge crack is analyzed.The possible fracture situation is predicted by combining the calculated threshold value of the edge crack of the high grade silicon steel.In this paper,the cause of the edge crack has been determined by the field sampling analysis,experimental analysis and finite element simulation analysis and other techniques when cold continuous rolling mill is rolling high grade silicon steel.the relevant technological parameters to solve this problem are put forward,which can effectively reduce the edge crack problem of the cold-rolled high grade silicon steel,and improve the product yield and product quality.