RELATION BETWEEN MICROSTRUCTURE AND CHIPP ING RESISTANCE OF FE-SI-AL ALLOYS

Cast Fe-Si-Ai alloys containing 0.5%Ti, 0 similar to 0.06%C, 0.2% rare earth metal, were prepared using a 10-kg vaccum induction furnace. Fe -Si-Al alloy cores for magnetic recording head were produced by grindi ng from those alloys which were hot-rolled and annealed at 900 similar to 1100 degrees C. In this paper, the effect of grain size on chippin g resistance in rough cutting, groove grinding and fine cutting of hea d-cores process is studied. The results obtained are as follows. 1 The methods to obtain a fine grain size of Fe-Si-Al alloy are ''hot-rolli ng'' and ''adding the minimum quantity of inhibiting grain-growth elem ents C, Ti, M. M. to alloy''. The former is the best method to obtain alloys with fine grains. 2 The larger the grain size in Fe-Si-Al alloy s, the more the number of chips increases. 3 Both the depth and the nu mber of chips are larger in cast alloys than hot-rolled and annealed a lloys. 4 Alloys with fine grains are obtained by the adding two elemen ts (Ti and C) to alloys rather than adding one element (Ti or C).