Except that the symbol “SM” is added at the head, the representation method of plastic mold steel is the same as that of high-quality carbon structural steel and alloy tool steel.
For example, the grade of carbon plastic die steel with an average carbon content of 0.45% is expressed as “sm45”; Alloy plastic die steel with average carbon content of 0.34%, chromium content of 1.70% and molybdenum content of 0.42% is indicated as “sm3cr2mo”.