HPT1 Screw
Wearing resistance, apply to 15% glass fiber, PF, Electric Driven Injection Molding Machine...

HPT2 Screw
Corrosion resistance: High speed and temperature resistance, PC with glass fiber, Nylon with glass fiber,

HPT3 Screw
HPT3: Non sticky, corrosion and wearing resistance; Applied to Magnetic powder, porcelain powder, Aluminum-Magnesium Powder, iron powder, bronze powder

HPT5 Screw
Sticky, corrosion and wearing resistance

All the above four are called hard screw, and have been used widely abroad, which have taken the place of bi-metal screw