Preventing the Formation of Copper Alloys of Tin, Antimony, and Arsenic on Steel Surfaces During Reheating to Reduce Hot Shortness.
The Bureau of Mines discovered that silicon and nickel additions can prevent the formation of copper alloys of sn, sb, and as on the surface of steel during reheating to hot-working temperatures. When molten, these copper alloys cause surface hot shortness during hot working. Wrought steels were reheated isothermally and by simulated industrial practice; the resulting surfaces were metallographically evaluated. The steels contained, in weight-percent, 0.20 C, 0.45 Mn, and up to 1.00 Si, 1.00 Cu, and 0.15 Ni, and up to 0.30 Sn, sb, or as. The larger the cu, sn, sb, and as content of the steels, the greater the amount of silicon necessary to prevent copper alloy formation. A content of 0.10 Ni considerably decreased the amount of silicon necessary for copper steels containing tin and antimony but not for those containing arsenic. Theories for the beneficial effect of silicon and nickel additions are presented.