STEEL AND METHOD FOR PRODUCING COMPONENTS WITH HIGH ABRASION RESISTANCE

摘要

An abrasion-resistant steel contains (by wt.%) 0.24-0.3 (pref. 0.24-0.27) C, 0-2 (pref. 0-1 Si) 0-2 (pref. 0-1) Al, 0-2 (pref. 0.3-1.6) Mn, 0-4 (pref. 0-2) Ni, 0-3 (pref. 0.5-1.8) Cr, 0-0.6 Mo and 0-1.2 W. The steel may also contain 0.005-0.005% B, at least one of Nb, V, Zr and Ti in amt. less than 0.3% and at least one of Se, Te, Ca, Bi and Pb in amt. below 0.1%, the rest being Fe. The following relationships also apply, 4.6C + 1.05Mn + 0.54Ni + 0.66(Mo + W/2) + 0.5Cr + k 1.6, where k = 0 if the steel contains less than 0.0005% B and k = 0.5 if the steel contains more than 0.005% B and 0.6% (Al+Si) 2%. To improve their abrasion resistance sheets of the steel are heated to above austenisation temp. (e.g. 900 degrees C) then cooled to 450 degrees C at more than 1 degrees C/s, further cooled to 200 degrees C over 50 s to 60 minutes (pref. 100 s to 30 minutes) and finally returned to ambient (below 250 degrees C) in less than 3 h. This gives the steel a martensitic or martensitic-bainitic structure contg. 5-15% austenite and a hardness of 400-500 HB.