Influences of Shot Blasting on Steam Oxidation Resistance of S30432 Boiler Tubes

The 1 000-hour steam oxidation test was carried out on the domestic and imported, with and without shot blasting S30432 steel tube samples at temperatures of 670 ℃, 730 ℃, 760 ℃ and 790 ℃, respectively. The analysis in respect of macroscopical quality, oxidation weigh gain and metallographic performance was also conducted on the samples after the test. The test results show that shot blasting on the tube inner surface can significantly improve the steam oxidation resistance of the S30432 boiler tubes, and the oxidation rate can be decreased by about an order of magnitude. In the test condition of 1 000-hour steam oxidation, the critical temperature of rapid oxide skin growth ranges between 730 ℃ and 760 ℃ for Sample 1 and between 760 ℃ and 790 ℃ for Sample 3. The critical temperature of imported tube samples is 30 ℃ higher than that of the domestic tube samples, which indicates the better steam oxidation resistance.