graphite rebar with good machinability and good kaltverformungseigenschaften and its manufacture method

摘要

Graphite steel for a machine structural use exhibiting excellent cutting characteristic, cold forging characteristic and fatigue resistance, the graphite steel for a machine structural use containing: C: 0.1 wt% to 1.5 wt%; Si: 0.5 wt% to 2.0 wt%; Mn: 0.1 wt% to 2.0 wt%; B: 0.0003 wt% to 0.0150 wt%; Al: 0.005 wt% to 0.1 wt%; O /= 0.0030 wt%; P /= 0.020 wt%; S /= 0.035 wt%; N: 0.0015 wt% to 0.0150 wt%; and a balance consisting of Fe and unavoidable impurities, wherein substantially overall quantity of C is precipitated as graphite and size of graphite is 20 mu m or less.