Helical screw for plastic extruder - having special corrosion and wear resistant tips to screw threads

摘要

Helical screw for plastic extruder is made of a steel core (2) with a monolithic support (3) for the threads (4). The support is made by hot isostatic pressing a metal powder which has good corrosion and wear resistant properties. Finally the thread covers (5) are hot isostatically produced using a metal with better wear and corrosion properties than that of the support (3). By hot isostatically forming the three parts together a diffusion layer is built between each part. ADVANTAGE - The screw is economically produced with good mechanical, corrosion and wear properties.