| 摘要 |
<p>1441032 Heat-treated steel machine elements K HEHL 29 June 1973 [5 June 1972] 30978/73 Heading C7A Plastification feed screws or plastification cylinders for use in plastics processing machines (e.g. injection moulding machines) are made of steel having a carbon content of at least 0À3% and a total content of carbide and super carbide (i.e. Cr, W, Mo and V) forming elements of at least 5%, balance Fe, have a tough resilient core and an abrasive resistant surface at least 2 mm deep formed by multipass induction heating the surface above the A.C. 3 point followed by quenching. Exemplary steels have high carbon (e.g. 1À65-2À2%) or medium carbon (e.g. 0À4-0À6%) contents. The heating may be effected in a series of passes with a pause therebetween, the holding temperature is preferably held for at least 120 secs. and quenching should not be by water. The final product may be annealed at 550‹C.</p> |
