粉末材料 焼結ステンレス鋼の耐酸化性

Abstract

The high temperature oxidation resistance of the sintered stainless steels was fundamentally investigated. Type 410L, 434L and 444L ferritic stainless steel powders, and type 310L and 316L austenitic stainless steel powders, moreover the pre-alloyed powders with addition of Si and Nb in type 310L and 410L stainless steels, were used. And these powders were compacted to the same sintered density by controlling the compacting pressure, then vacuum-sintered at 1473K for 3.6ks. The oxidation tests at 1123K in air and the cyclic oxidation tests at room temperature-1123K in the exhaust gas were performed. The results obtained are as follows: (1) As for the high temperature oxidation tests in air, Si and Nb addition little affected oxidation resistance in both of the sintered 310L austenitic and sintered 410L ferritic stainless steels. (2)And it is obviously shown that the oxidation behaviors were influenced by sintered densities, especially by the open porosities. The oxidation resistance depended on the sintered density and more strongly on the open porosity than on the chemical compositions of sintered materials. (3) On the same manufacturing condition, the oxidation resistance of sintered ferritic stainless steels was better than that of sintered austenitic stainless steels, because their powders densified easier than austenitic stainless steel powders. (4) As for the cyclic oxidation test in exhaust gas, the spalling of the oxide scale occurred to the sintered 410L . But the sintered 410L-2Si was