亚硫酸盐对热镀锌钢材在海洋大气环境中氢吸收行为的影响

Effect of Sulphite Deposits on Hydrogen Embrittlement Susceptivity of Hot-dip Galvanized Steel in Marine Atmospheric Environment

采用改进的Devanathan双面电解池检测了热镀锌钢材的氢渗透电流,结合慢应变速率拉伸试验和断口形貌分析,研究了受工业海洋大气污染有亚硫酸盐沉积的热镀锌钢材氢吸收行为及其在此环境中的氢脆敏感性。结果表明:随着试样表面亚硫酸盐的增加,其氢渗透电流显著增大;镀层缺陷使试样的氢渗透电流增大,且亚硫酸盐与镀层表面的缺陷协同效应进一步促进热浸镀钢材的氢吸收行为;氢吸收降低了热镀锌钢材的断后延伸率,表明海洋大气中的亚硫酸盐污染物会降低热镀锌钢材的韧性,导致氢损伤。

Hydrogen permeation and embitterment behavior of hot-dip galvanized steel with different amount of sulphite deposits on surface exposed to stimulant marine atmospheric environment was investigated. The hydrogen embrittlement susceptivity of the steel in this environment was assessed through measuring the hydrogen permeation current by an improved Devanathan-Stachurski cell and the elongation of the galvanized steel at break, while observing the morphology of the fractured surface. Results indicated that the hydrogen permeation current gradually increased with the increasing amount of deposits.On the other hand, it was found that hydrogen absorption was accelerated by the synergistic effect of cathodic protection and the existed damage of zinc coating induced by scratching. The adsorbed hydrogen can reduce the elongation of the steel at break. This means that sulphite can reduce the toughness of hotdip galvanized steel, resulting in hydrogen damage.