高周波焼入れの疲れ強さに関する影響についての一実験 : その6,中空にした影響

抄録

The authors have conducted fatigue tests on the V-notched and plain specimens (d=15 mm, C=0.37% steel). Two types of heat-treatment have been chosen : induction-hardening method and quenching-tempering. Some of these specimens were made hollow and were drilled following heat-treatment. The experimental results may be summarized as follows : 1) There is small difference in σ_w1, but a considerable difference in σ_w2, between the solid and hollow specimens which are induction-hardened, V-notched. For example, in solid specimens, σ_w1 is 18kg/mm² and σ_w2 in 56kg/mm², while in hollow ones (d_i=10 mm) σ_w1 is 17kg/ mm² and σ_w2 is 18 kg/mm². 2) There is no great difference between fatigue limit of induction-hardened solid plain specimens and that of induction-hardened hollow plain ones. 3) When the induction-hardened depth becomes larger, the fatigue strength of V-notched solid specimens becomes smaller, especially the value of σ_w2. But, the fatigue strength of plain specimens becomes slightly larger. 4) For quenched and tempered V-notched specimens σ_w1 is nearly equal to (σ_w0/α). 5) The effects of residual stress on the fatigue strength are different depending on shapes, size of sqecimens, stress-conditions, etc., and are very much complicated.