SUH 31 合金の諸性質におよぼす添加元素の影響について(性質関係)

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For valve alloys are required higher tensile strength, creep-ruptuer and fatigue strength at elevated temperatuers and high resistance to accelerated corrosion, by sodium, sulfur and vanadium in fuel. SUH 31 alloy has been developed as the most suitable alloy for exhaust valve. We have tested the effects of alloying elements of Cr, Mn, Si, Nb and B of SUH 31 alloy. The rusults obtained are as follows : 1. Short time tensile strength increased by 2.0∿7.0 kg/mm^2 higher than SUH 31 alloy by adding a small amount of N and 6.0∿8.0% Mn instead of Ni. There was no change in the tensile properties by increasing Cr to about 19% and by varyng Si between 1.0% and 3.0%. 2. Creep-rupture strength increased remarkably by adding both B and N, but reduced by adding Cr, Mn and C respectively. 3. Cr was an effective element for the hot corrosion resistance. The optimium Cr content was about 19.0%. Si did not show a good effect on hot corrosion resistance by any immersion crucible tests at 800℃, but at 900℃. Replacement of Ni by Mn gave a good effect for the test in synthetic ash containing 20 wt% of Na_2SO_4.
社団法人日本鉄鋼協会の論文
1970-02-01