The production flow sheet of tested high grade non-oriented silicon steel (/% : 0.006C

3.28Si

0.22Mn

0.030P

0.007S) is 180t BOF-vacuum refining-230mm x(900~1750)mm slab casing-hot rolled to 2.02mm plate-cold rolled to 1.65mm sheet. The causes and mechanism of edge cracks of cold rolled high grade silicon steel sheet are analyzed by testing edge composition and structure

mechanical properties

micro morphology of cutting side and fracture of hot rolled base plate. Results show that the edge crack of cold rolled sheet of high grade silicon steel is cleavage fracture

the mixed grain structure existing in edge of hot rolled plate led to decreasing plasticity and round saw cutting to cause crack and small pits in cutting band are main reason lo cause edge cracks in cold rolling process； besides the segregation of S and Mn at edge fracture is an important factor for the cracks initiation. With the measures including decreasing the temperature differential between edge and middle during hot rolling process

decreasing the side interval of round cutter to 280 μm from 410 μm after hot rolling

and improving the electromagnetic stirring parameters from 380 A/3 Hz to 350 A/6 Hz

the occurring rate of edge cracks of high grade silicon steel cold sheet decreases from original 14% to 4%.