... ,4040 diameter:12-400mm length:6m or more for industry alloy steel round barstandard:Chinese GB,ASTM, DINMaterial:42CrMo ... ,42CrMo4,4040diameter:12-400mm length:6m or morefor industry,etcapplication:gear,backshaft,drill pipe,mouldand etcchemical composition: ... cylinder, spring, 1200mm~2000mm rotary shouldered connections for petroleum industry, jar knocker, substitute of hardened and tempered steel ...