... gears (spur gear, bevel gear, sprial gear, ring gear, internal gear, sprocket, chain wheel) transmission, gear box, reducer ,shaft and ... tempering.StandardISO, GB, JIS, DIN, AGMA and non-standardSurface TreatmentCarburizing, hardening and tempering, Nitriding, high frequency treatment, black ... by our well-trained and proffesional engineer and staffs.4. Special discount and protection of sales area ...