Silicon steel sheet is a kind of soft magnetic alloy made of ferrosilicon with very low carbon content and little silicon content. Silicon steel sheet can be divided into two types according to their silicon content, low silicon and high silicon, low silicon chip contains less than 2.8% silicon. It is mainly used for manufacturing motor, commonly known as motor silicon steel sheet; high silicon chip silicon content is 2.8% - 4.8%, which has good magnetic but relatively brittle, mainly used for the manufacture of transformer core, commonly known as transformer silicon steel sheet. There is no strict limit between the two in practical use, and large motors are usually manufactured by high silicon chips. Cold rolling can be divided into two kinds: non orientation and grain orientation. The cold rolled sheet has uniform thickness, good appearance quality and high magnetic properties. According to the production and processing technology, it can be divided into two types: hot rolling and cold rolling. Therefore, with the development of industry, hot rolled sheet has the tendency of being replaced by cold rolled sheet.