鋼の引張り延性の異方性に及ぼす非金属介在物の影響

抄録

The effect of non-metallic inclusions on the anisotropy of tensile ductility of low-alloy steels having the tensile strengths lower than 100 kg/mm² was studied. The test results were as follows: (1) Beyond the tensile yielding stress many micro-cracks were formed at the extremities of the inclusions and the size and the distribution of these micro-cracks were responsible to the anisotropy of the ductility. (2) when the specimen was taken from the heavily segregated region, many inclusions were contained and even the tensile strength was lowered by these inclusions. (3) the anisotropy of the reduction of area of twelve 3%Ni-Mo-V steels, having four different sulfur contents and subjected to forging of three different rates, was increased proportionally to the sulfur content and the forging rate, but the anisotropy of the segregated region may be influenced by the segregation of not only sulfur but also the other alloying elements.