Screw diameter: 35mm-200mm Length: less than 10000mm Barrel diameter: 35mm-200mm Material: 38crmoala; skd61; skd11; 40cr; 42crmo; high quality alloy steel Technology for tin coated screw barrel/: nitriding treatment, alloy coating spraying, heat-treatment, quenching Appliance for tin coated screw barrel/: pa, evoh, eaa, pc etc