Experimental Study on Thermokinetics of Hydrogen Enrichment and Release In X17CrNi16-2 Stainless Steel Melts
摘要
This study conducted hydrogen enriching and releasing experiments on stainless steel X17CrNi16-2 in a vacuum tube furnace. The results showed that at 1823 K and hydrogen pressures of 0.06, 0.08, and 0.10 MPa, hydrogen mass fraction in the steel reached 18.5 × 10−6, 20.1 × 10−6, and 22.5 × 10−6, respectively. During vacuum treatment at pressures of 0.02, 0.03, and 0.04 MPa, hydrogen release lasted 5 minutes, with hydrogen mass fraction reaching 11.1 × 10−6, 13.4 × 10−6, and 15.5 × 10−6. Both the hydrogen enriching and releasing processes approached equilibrium approximately and conformed to Sievert's law. In the initial 80 pct stage of hydrogen enriching, the rate was controlled by hydrogen mass transfer within the steel, with a mass transfer coefficient of 0.144 cm/s. In the final 20 pct stage, a combination of the interfacial chemical reaction and hydrogen mass transfer controlled the rate, with the interfacial reaction playing a larger role, was addressed. During the hydrogen releasing experiments, the appearance of bubbles in the first minute made the kinetic integral equations inappropriate for data fitting, and hydrogen mass transfer within the steel was the rate-limiting step. After the first minute, the hydrogen release rate significantly decreased, controlled by a combination of hydrogen mass transfer and the interfacial chemical reaction, with hydrogen mass transfer being dominant. The equilibrium constant KH for the reaction