What do the S7 and D3 Steel refer to? Are they stainless steels, if not what kind of steel types are they?
S7 S7 is the most commonly used standard steel for punches. The “S” in S7 indicates that it is Shock Steel because it is made to withstand high shock forces. The “7” refers to the chemical composition of the steel. There are several grades such as S1 and S5. D3 The “3” in D3 would again refer to the chemical composition. The “D” in D3 indicates that it is die steel. It is the type of steel that metal stamping and forming dies are made from. It is a common misconception that punches and dies are manufactured from stainless steel. Although tooling can be made from 440C Stainless Steel, it is not a true “stainless” due to its carbon content, required for hardening. This steel is classified as corrosion resistant but can still rust or discolor. All of the other steels used are classified as tool steel. To better understand different steel types and their characteristics click to view the charts below: TSM6_PG76.pdf TSM6_PG77.
