Fatigue Crack Propagation Behavior of Two-layered Low Carbon Steel-stainless Steel Composite Plates

Abstract

Fatigue crack propagation tests were conducted on butt-bonded two layered composite plates consisting of a low carbon steel and a ferritic or austenitic stainless steel under pulsating tension varying from zero to maximum, to study the effects of residual thermal stress and the difference in mechanical properties on the crack propagation and crack opening behaviors. It was observed that the propagation behavior of fatigue crack in the composite plate was rather complicated when the crack growth rate was plotted against K_max. And it was found that ΔK_eff was a much better parameter for controlling the crack propagation in the composite plates, though not completely sufficient. In discussions it was shown that the crack opening behavior in the composite plate was well estimated by considering an initial distribution of the residual stresses and the crack opening behavior of the monolithic plate, when the crack propagated in the field of compressive residual stress. But this was not the case, when the crack was in the field of tensile residual stress.