Fatigue Strength of Sprayed Specimen

Study on Flame Spraying (Report 1)

Abstract

Various methods of surface treatment have been performed for improving the properties of metals and alloys. Among these surface treatment, the flame sprayed coating technique is selected, since this technique is expected to be one of the effective methods for the surface treatment.
The flame spraying used for this experiment has low cost equipment and easy maintenance, and can be adopted in various places and forms.
In this paper, the fatigue strength of the high strength steel (HT 60) is examined by the sprayed specimens with four kinds of thermal spray materials (Zn, Al, ceramics and metallizing alloy).
The results are as follows:
1) The surfaces of the turning and blasted specimens have a little higher hardness due to the work hardening effect.
2) The fatigue limit of the rotate-bending fatigue test is the same as that of the blasted specimen, and it has no relation to the blasted specimen and the kinds of spray material except the metallizing alloy material.
3) The microstructure of the base metal near the sprayed coating is the mixture of ferrite and pearlite.
4) The micrography of the fatigue fracture surface shows mainly dimple and quasi-striation pattern.