Abstract
Stellite alloys have excellent erosion resistance and are used for valves as weld overlays. It is important to fabricate the weld overlays in our laboratory for better understanding. Stellite has a problem that radiation quantity increases in the plant, when the stellite is exposed to radiation. Therefore, Co-free alloy is desired as an alternative erosion resistant material. In our laboratory, we found that Ti-Ni shape memory alloys (Ti-Ni SMAs) have an excellent erosion resistance. We examined the Ti-Ni alloys as a surface coating. In this study, cavitation erosion tests were carried out by using weld overlays of stellite alloys and Ti-Ni alloys which were made with our weld overlay apparatus. The results showed that the erosion resistances of weld overlays of ST6 and ST21 are about 12-15 times higher than that of SUS304, thus weld overlays of stellite alloys show excellent erosion resistances. Moreover, we found that the erosion resistances of weld overlays of Ti-Ni alloys are about 2-14 times higher than that of SUS304, thus the erosion resistances of weld overlays of Ti-Ni alloys are the same or higher than that of stellite alloys. By using arc melting furnace, the erosion resistance of the arc melting alloys were compared with that of weld overlay.
