STEEL COMPOSITION FOR SUSPENSION SPRINGS

摘要

A steel composition is provided having improved sag resistance and fatigue behaviour properties adapting it to be suitable for coil and torsion bar suspension springs for passenger vehicles and light trucks of lesser weight. Critical to the composition is the use of vanadium in an amount of from about 0.05 to about 0.50 wt% or niobium in an amount of about 0.05 to about 0.20 wt%, sufficient nitrogen to ensure that the vanadium or niobium is in the form of vanadium nitride or niobium nitride respectively and the substantial absence of aluminum. The vanadium nitride or niobium nitride ensures fine grain formation and the improved properties. Other components may be present including carbon, silicon and chromium.