MANUFACTURE OF FERROMAGNETIC NI-FE ALLOY AND SLAB OF THE SAME ALLOY HAVING EXCELLENT SURFACE PROPERTIES

摘要

A ferromagnetic Ni-Fe alloy consisting essentially of: -nickel from 75 to 82 wt. %, -molybdenum from 2 to 6 wt. %, -boron from 0.001 to 0.005 wt. %, -calcium within the range satisfying - any one of the following formulae - in a weight ratio to sulfur as an - incidental impurity, depending upon - an oxygen content as an incidental - impurity: - 1.5 /= Ca/S /= 3.5, - or - 1.15 /= Ca/S /= 3.50, - and the balance being iron and incidental impurities. Said alloy may further additionally contain from 1 to 5 wt. % copper and/or from 0.1 to 0.4 wt. % manganese. An alloy article such as a slab or a strip having an excellent surface quality of said alloy is manufactured by heating a material having the above-mentioned chemical composition to a temperature of from 1,100 DEG to 1,250 DEG C., and then hot-working the thus heated material at a finishing temperature of at least 800 DEG C.