Low carbon steel-high silicon electrical steel-low carbon steel three layers composite plate prepared by cladding cast has been deformed by process of hot rolling and warm rolling. The formation and evolution of cracks during the plastic process are investigated

and the effect of diffusion annealing on variation of cracks in deforming process is studied. Results show that ingot of composite could be thinned by hot rolling and warm rolling from 60 mm to 0.5 mm. The deep cracks in high silicon electrical steel generated during plastic deformation process are not affected by the processing technique essentially and their own existence attribute will always be retained in inner layer of the composite. The ordinary cracks produced in the deformation process are greatly affected by the deformed process

and the size decreases obviously. The microcracks generated in the alloy matrix around the deep crack and ordinary crack during the plastic process can be eliminated in the diffusion annealing process.