低ΔK領域における単一引張過大荷重による疲労き裂伝播の遅延現象に及ぼす溶接引張残留応力の影響

抄録

Effect of welding tensile residual stresses on fatigue crack growth retardation following single tensile overload in low ΔK region was studied experimentally. Material used was steel of 800 MPa in tensile strength. Specimens were center-cracked-plates and consisted of two kinds; specimens without weld, specimens with longitudinal weld. Major results obtained are summarized as follows:
(1) Tensile residual stresses decreased the level of crack growth retardation.
(2) Compressive overload succeeded to tensile overload decreased the level of crack growth retardation. Especially the effect was more remarkable in specimens with longitudinal weld.
(3) The retardation couldn't be explained from crack closure behavior.