... gear, bevel gear, sprial gear, ring gear, internal gear, sprocket, chain wheel) transmission, gear box, reducer ,shaft and sleeve etc ... treatment to decrease noise and increase load capacity.MaterialCarbon Steel , alloy steel , stainless steel , aluminum alloy , zinc alloy , brass , gray iron , nodular ... teeth of gear.CertificateISO9001:2000Minimum quantityAccept trial order 20CrMnTi steel spur gear