抄録
The effects of surface decarburization on the fatigue properties of 0.6%C carbon steel, whose depth decarburized ranges from 0.17mm to 0.5mm, were obtained by the two types of test specimens, A-type the bar stock piece and B-type the filleted piece; and these specimens consist of two groups of structures, that is, a normalized one and a quenched-tempered one.
As the depth decarburized increases, the tensile strength of normalized steel decreases; the elongation, contraction of area and impact value have the minimum value at the depth decarburized 0.2-0.3mm.
Due to the surface decarburization, the fatigue limit were remarkably reduced, and their decreasing rates get greater up to about the 0.3mm depth decarburized. By a quenching-tempering treatment, the fatigue durability becomes greater than that of normalized steel.
The fatigue limits for A-type specimens are less than those for B-type ones. This reason appars to be the occurence of fretting corrosion on the holder part of specimen. But the detriment of fretting corrosion for fatigue limit appears to be diminished by the skin free ferrite on the surface of specimens obtained br decarburizing.
