回火温度对2Cr13钢在H2S-CO2环境中腐蚀的影响

为了研究回火温度对2Cr13钢在H2S-CO2环境中腐蚀的影响,首先分析了3种热处理状态下2Cr13钢的显微组织,再利用失重法测试了2Cr13钢在不同回火温度下的腐蚀速率,利用表面形貌法观测了2Cr13钢的腐蚀产物形貌及产物组成,最后利用电化学方法分别测试了3种热处理后2Cr13裸钢和在H2S-CO2环境中腐蚀72 h后试样的动电位极化曲线。结果表明:在正火状态下2Cr13钢的显微组织为富Cr铁素体加粒状未溶碳化物,600,700℃回火处理的显微组织为板条马氏体加碳化物;3种热处理状态下,正火处理的2Cr13钢的耐H2S-CO2腐蚀性能显著;正火处理的2Cr13钢中的游离Cr质量分数高,在H2S-CO2环境中将生成完整、致密的腐蚀产物膜,而回火处理的2Cr13钢中的游离Cr质量分数降低,生成疏松的腐蚀产物膜。

Effect of tempering temperature on corrosion resistance of 2Cr13 steel under H2S-CO2 coexistence environment

In order to study the effect of tempering temperature on the corrosion resistance of 2Cr13 steel under H2S-CO2 coexistence environment,firstly,the microstructure of 2Cr13 after three heat treatment states was studied,and the corrosion rates at different tempering temperature of 2Cr13 steel were obtained by weight loss method.The morphology and product composition of the corrosion products of 2Cr13 steel were observed by surface morphology method.Finally,the polarization curves of bare steels and the samples corroded under H2S-CO2 environment for 72 h were tested with electrochemical method.The results show that the microstructure of 2Cr13 steel in normalized state is chrome-rich ferrite and granular undissolved carbide.The microstructure after tempering at 600°C and 700°C is lath martensite structure and carbide.Among the three tempering treatment states,the 2Cr13 steel treated in the normalized state has remarkable corrosion resistance to H2S-CO2.In the H2S-CO2 environment,the free Cr stored in the 2Cr13 steel after normalizing will form a complete and dense corrosion product film,while the Cr content in the 2Cr13 steel after tempering is reduced to form a loose corrosion product film.