Powder metallurgical cold work steel - useful for processing abrasive and corrosive plastics

摘要

(A) a novel powder metallurgical cold work steel has the compsn. (by wt.) 2.2-2.5% C, 19.5-24.0% Cr, 0.9-3.0% Mo, 3.5-4.5% V, 1.6-3.0% Ta and/or Nb, 0.01-0.1% B, 0.05-0.09% S and balance Fe. (B) prodn. of the cold work steel involves preparing a melt of compsn. as in (A), atomising to powder of less than 1mm. particle size and then sintering or hot isostatically pressing to a body of more than 99.99% density. USE/ADVANTAGE - The cold work steel is useful for processing plastics esp. filled, highly abrasive and corrosive plastics. It has an extremely good combination of wear and corrosion resistance has optimal strength and toughness, is machinable in the soft condition and has a homogeneous, segregation-free, pore-free and very fine grain structure providing quasi-isotropic properties.