X線フラクトグラフィにおけるK_<max>、ΔK_<eff>の推定曲線に及ぼす焼もどし温度の影響

概要

論文の詳細を見る
Fatigur tests were carried out under various load controlled conditions using a Ni-Cr-Mo steel, JIS SNCM 439 equivalent to AISI4340, tempered at three different temperatures. The residual stress was measured by an X-ray diffraction method on the fatigue fractured surface. The relation between the residual stress and the stress intensity factor was discussed. The main results obtained were as follows: (1) The residual stress on the fatigue fractured surface was separated into the tensile and compressive components and the relations between these components and the stress intensity factor were established quantitatively for the three tepering temperatures. (2) The fatigue crack propagation rate could be estimated by using the results(1). (3) The tensile residual stress component was higher for lower tempering temperature. (4) The maximum value of the tensile residual stress component was nearly equal to the yield stress of the material. (5) The absolute value of the compressive residual stress component was higher for lower tempering temperature. (6) Under the positive load ratio, the residual stress on the fatigue fractured surface was not affected by the contact of the fractured surfaces due to the crack closure. (7) The effect of roughness on the shape of the estimated curve could be intored if the roughness was nearly constant through out the whole range of stress intensity factor.
社団法人日本材料学会の論文
1993-06-15