Free cutting low alloy steel resistant to dynamic stresses - comprising manganese, silicon, lead, calcium, niobium or vanadium, zirconium or cerium and molybdenum or nickel (PT 7.2.80)

摘要

High strength, free-cutting steel capable of supporting dynamic stresses, even without tempering, comprises (by wt.) 0.20-0.70% C; 1.20-3.00% Mn; up to 1.00% Si; at most 0.04% P; 0.05-0.11% S; at least 0.10% Pb; 0.001-0.03% Ca, 0.001-0.005% B; 0.007-0.035% N; 0.03-0.20% Nb and/or V; at most 0.25% Zr and/or Ce; at most 0.2% Be and/or Bi and at most 1.00% Mo and/or Ni; balance Fe.. The steel is used for fabrication of machine parts which are submitted to high stresses. The steel is readily machinable using automatic machining techniques, so that the turnings are readily removable automatically by the coolant liquid, without external intervention. The resistance to dynamic stresses is superior to those of prior free cutting steels.