Steel for a vehicle suspension spring having good sag-resistance

摘要

A steel for use in a vehicle suspension spring having a good sag-resistance comprising by weight 0.50-0.80% carbon, 1.50-2,50% silicon, 0.50-1.50% manganese, a member or members selected from a group consisting of 0.05-0.50% vanadium, 0.05-0.50% niobium and 0.05-0.50% molybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting of 0.0001-0.01% boron and 0.20-1.00% chromium, and not greater than 0.0008% nitrogen.