Barrel is made from alloy steel and nitride hardened, and precisely honed to fine inner surface. Water circulation jacket is provided with hopper in feeding zone. Barrel is divided in to (equal) zones for heating. Nitrided Nitro Alloy SteelScrew is made from alloy steel and to be hardened and chrome plated. It is fitted on a heavy thrust gear box to withstand the pressure during extruding the TUBE. Screw is driven by induction motor AC motor Ac variable speed drive through a suitable gear box of standard make.