Synopsis: The authors have made a study of some effects of rare earths adlition to steel for these several years. In this report, the influences of addition of the RE (rare earth)-Ca-Si complex alloys (of domestic commercial product) to stainless steels (AISI type 201, 202, 304 and 430), stainless alloy (20 series, equivalent to Carpenter 20) and heat resistant alloys (Iron-base Ni-Cr-Mo, equivalent to Timken 16-25-6; Ni-base, to Nimonic 90; and Fe-Cr-Al alloys) are summarized. The ingot

more »

... of type 304 and 20-series alloy were 30---50 kg, and those of other laboratory-made ones were about 4kg, and 0 ' l5'--06 wt% of RE-alloys were added in the furnace just before casting. Besides, to check up the influence of calcium and silicon contained in RE alloy, comparative specimens (added 02-05 wt% of Ca-Si alloy) of type 201, 202 and 430 steels were melted, respectively. The authors investigated mainly the effects of RE-alloys upon microstructure, mechanical properties, ductility at high temperature, anticorrosion and oxidation properties: particularly, on the subject of ductility at high temperature, sub-size impact, impact-bending, torsion, bending and tensile tests were carried out elaborately. Main results of experiments obtained are as follows: (1)Treatment with RE-Ca-Si decreased the non-metallic inclusions in alloys, especially A-series(ductile sulphides and silicates)and B-series(alumina),and it appears better to use RE-Ca-Si than to use RE metals or Ca-Si alloy alone.