METHOD FOR REDUCING SURFACE FLAW IN THE STAGE OF RAPIDLY SOLIDIFYING HIGH NI-FE ALLOY

摘要

PURPOSE:To effectively reduce the generation of surface flaws in the stage of rapidly solidifying the high Ni-Fe alloy, in an alloy having high Ni content and contg. Mo and/or Cu, by retaining the wt. ratio of Ca to S as inevitable impurities into a suitable range and furthermore adding suitable amounts of B thereto. CONSTITUTION:At the time of casting a high Ni-Fe alloy contg., by weight, 76 to 82% Ni and 2 to 6% Mo into =10mm plate thickness by a rapid solidifying process, in addition to the above alloy components, the following components are furthermore added thereto and the content of inevitable impurities is regulated in the following manner: Namely, 0.001 to 0.005% B and suitable amounts of Ca are added to the above high Ni-Fe alloy. In this case, as for the inevitable impurities, =0.001% S, =0.006% P, =0.003% C, =0.003% O and =0.0015% N are regulated. In this way, the generation of surface flaws in the stage of rapidly solidifying the above high Ni-Fe alloy is effectively reduced and a flaw removing stage is drastically cut down, by which the improvement of the yield and the reduction of the manufacturing cost can be attained.