
8 fully reserved elements
Ni, Co, W and Mo can improve the hardenability of steel and are beneficial elements; Cu can cause copper embrittlement during high-temperture hot working of steel, but on the other hand, it can improve the ability of steel to resist atmospheric corrosion; Residual elements Sn, As and Sb are harmful elements, which not only strengthen copper brittleness in steel, but also lead to the brittleness of second tempering of alloy steel; Sn is one of the extremely harmful residual elements in steel, and Sn will greatly reduce the high temperature mechanical properties of steel and alloy.
7 partially reserved elements