Fatigue properties improvement of stainless steel 1Cr18Ni9Ti welded joints by plasma spray process

Plasma sprayed coatings on the weld toe can modify the sectional dimensions of welded joints.It can also reduce the stress concentration of the toe.So the fatigue properties of the joints can be improved.The plasma spray process was used to improve fatigue properties of welded joints.The fatigue tests of the cruciform joints welded by TIG welding of stainless steel 1Cr18Ni9Ti under tensile load(R=0) were carried out on the as welded,flame sprayed and plasma sprayed specimens.Fatigue tests results showed that plasma spray process was effective to improve fatigue life of cruciform joints.The fatigue strength of the as welded specimens was 169.8 MPa,and that of the flame sprayed and plasma sprayed specimens were 186.2 MPa and 213.8 MPa respectively.The fatigue strength of the plasma sprayed specimens had been increased by 25.9%,and that of the flame sprayed had been increased by 9.7%.The fatigue life of the plasma sprayed specimens was 1.58~9.62 times longer than that of the as welded ones,and that of the flame sprayed specimens was 1.55~1.97 times longer.