alloy round bar standard:Chinese GB,ASTM, DIN Material:a42CrMo,42CrMo4,4040 ... 4040diameter:12-400mm length:6m or morefor industry,etc application:gear,backshaft,drill pipe,mouldand etc chemical composition:C: 0. ... for making important machinery parts, such as bearing, gear, connecting rod, transmission gear, supercharger gear, engine cylinder, spring, 1200mm~2000mm rotary shouldered connections ...