【摘要】 石油管常用材质J55和N80钢的腐蚀穿孔严重影响了油田的正常生产,而采取热浸镀铝可以有效地提高其耐热性和耐蚀性。研究了热浸镀铝的工艺条件,确定了石油管热浸镀铝的最佳工艺为熔融熔剂法中的二浴法。在此工艺基础上,采用金相显微镜对J55和N80钢的镀层厚度及显微结构进行了分析,同时采用全浸法研究了J55和N80钢热浸镀铝前后在3%NaCl水溶液中的耐蚀性,并利用CMP系列拉力强度试验机比较了镀铝前后J55和N80钢力学性能的变化。结果表明:J55和N80钢热浸镀铝后的镀层组织均可分为纯铝层和铁铝金属间化合物层两层;经热浸镀铝的J55和N80钢耐3%NaCl盐水腐蚀性能显著提高,而力学性能却有所下降,其抗拉强度由于高温回火、碳化物长大等原因分别降低了10.5%和8.2%。更多还原

【Abstract】 The oil pipes made of J55 and N80 steels are liable to corrosion-induced perforation, which leads to serious obstacle and damage to the safe production in oil fields. Fortunately, it is feasible to greatly increase the heat-and corrosion-resistance of the steels making use of hot-dip aluminizing. Thus a study was made with respect to the optimization of hot-dip aluminizing technology for the oil pipe steels, and the two-bath flux method was established as the optimal aluminizing technology for the oil pipe steels, based on comparison with various other methods for aluminizing. The thickness and microstructure of the resulting hot-dip aluminizing coatings on J55 and N80 steels were analyzed by means of optical microscopy. The corrosion resistance of the J55 and N80 steels, with and without the hot-dip aluminizing coatings, immersed in aqueous solution of 3% NaCl was comparatively evaluated, while the fracture strength of the J55 and N80 steels with and without the hot-dip aluminizing coatings was determined using a pull-force machine for strength measurement. The results showed that the hot-dip aluminizing coatings on both the J55 and N80 steels were composed of aluminum layer and Fe-Al intermetallic compound layer. The J55 and N80 steels coated with the hot-dip aluminizing coatings showed better corrosion resistance than those without the aluminizing coatings, but the mechanical strength of the aluminized steels was decreased to some extent. Namely, owing to the tempering at high temperature and growing up of carbides during the aluminizing process, the fracture strength of the aluminized J55 and N80 steels dropped by 10.5% and 8.2%, respectively, as compared to those without aluminizing.更多还原