... kinds of gears (spur gear, bevel gear, sprial gear, ring gear, internal gear, sprocket, chain wheel) transmission, gear ... TreatmentCarburizing, hardening and tempering, Nitriding, high frequency treatment, black of oxidation, zincing.FinishingSand blasting , polishing , plating , acid ... your need for high precision on teeth of gear.CertificateISO9001:2000Minimum quantityAccept trial orderTrade term: ...