... (wear-proof, corrosion-proof, heatproof, high-pressure proof and high-speed proof):HPT1 HPT2 HPT37)depth of the double alloys : ... single screw extruders, 30-130mm tapered and parallel double screw extruders, rubber machinery, and petroleum machinery. Technical index: 1)Depth ... wear-proof, corrosion-proof, heatproof, high-pressure proof and high-speed proof):HPT1 HPT2 HPT3 7)depth of the double alloys ...