... iron, ductile iron rings;keystone ring, taper ring, drum ring;Chroming ring, spray molybdenum ring.Capacity:40 Millions Pcs/year.2 ... ket equipments for producing piston rings and inspections instruments from Germany,Japan,USA,France etc.According to ... the barrel surface ring,keystone surface ring,cone surface ring,twist side ring,chromium plating ring,spray molybdenum ring,nitride ring,steel disc rng ...