A study of fatigue behavior has been carried out using a set of commercial surfacing chromium steels in the state of deposits postheated at 350°C. The set consisted of various filler metals with different contents of chromium, nickel, carbon, and carbide-forming elements. It has been found that all the deposits examined are characterized by very close values of their fatigue crack growth threshold, ΔKth. In each material, as the stress intensity factor range is varied, three different propagation kinetics are observed, probably triggered by the presence of trapped hydrogen. Fracture toughness and, even though less strictly, subcritical growth by fatigue depended on the vanadium or columbium contents of each material, rather than on the other alloying elements. By adding vanadium or columbium and increasing the columbium content, one obtains a sharp decrease in plane-strain fracture toughness. No interdependence has been found between the values of the fracture toughness and the impact toughness of each material. This apparent discrepancy between the two kinds of toughness can be explained by using a distance criterion for failure at the tips of sharp cracks.

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