13%Cr鋼の機械的強度に及げす非金属介在物およびMoの影響

Abstract

The experiments herein introduced were made to clarify the tensile, impact, fatigue and creep strength of 13% Cr steel at high temperatures, and the effect of non-metallic inclusions and the Mo on the mechanical strength of the alloy.In the experiments on the effect of non-metallic inclusions, four types of specimens were used, which contained 0•13 to 0•20% C, 12•69 to 13•13% Cr and various quantities of nonmetallic inclusions. For testing the effect of Mo, five types of specimens containing 0•09 to 0•17% and trace to 1•06% Mo were employed.The results are summarised as follows.(1) Tensile strength is not affected by the non-metalljc inclusions.(2) With the increase of temperature, the tensile strength and the fatigue strength decrease, but endurance ratio, (i. e. fatigue strength divided by tensile strength, ) increases.(3) The impact value is lowered by inclusions only slightly at room temperature but considerably at high temperatures.(4) Rotating -bending fatigue strength decreases with the increase of inclusions on the stressed surface.(5) Addition of Mo increases the tensile strength and particularly creep strength at high temperatures, but affords no change in fatigue strength. 13% Cr steel containing 1.06% Mo has about twice the creep strength of that containing no Mo.