... is applied to prevent fatigue crack.Crank shaft (material used: 35CrMo, 4140,1045,QT800)Nitrogen hardening treatment is ... applied to attain strong strength, high hardness, durable and corrosion resistant feature.Plunger (material used: superior ceramic, Colmonoy coated, ... special specification can be provided to the users. high pressure steam boiler feed water pump,high pressure boiler feed water pump