Cr5Mo钢表面纳米化及退火处理对其流动加速腐蚀性能的影响

Effects of Ultrasonic Shot Peening Surface Nanocrystallization and Annealing on Flow-Accelerated-Corrosion Behavior of Cr5Mo Alloy Steel

为了探讨Cr5Mo钢表面纳米化及纳米化后退火处理对其流动加速腐蚀性能的影响,采用超声喷丸技术对Cr5Mo合金钢进行表面纳米化,采用温度、压力、流速可控密闭流动加速腐蚀试验机,对纳米化及纳米化后退火处理的Cr5Mo钢在含50 mg/L H2S去离子水溶液中的流动加速腐蚀性能进行了研究;采用扫描电镜(SEM)对腐蚀产物膜微观形貌进行了分析。结果表明:Cr5Mo钢表面纳米化后抗流动加速腐蚀性能增强,表面生成的腐蚀产物膜较致密;随着冲击强度的增加,腐蚀产物膜的致密度和完整性变差,耐蚀性能逐渐下降;纳米化后退火处理的试样腐蚀速率呈增大趋势,但随着退火温度的升高而降低,随保温时间的延长先减小后增大,保温时间2 h时腐蚀速率最小。

For investigating the effects of surface nanocrystallization and annealing treatment on the flow-accelerated-corrosion behavior of Cr5Mo alloy steel,ultrasonic shot peening technology was used to conduct surface nanocrystallization of the steel. The flow-accelerated-corrosion behavior of Cr5Mo alloy steel after surface nanocrystallization and of the same steel after surface nanocrystallization plus annealing treatment in deionized water solution containing 50 mg / L H2S was evaluated with an air-tight flow-accelerated-corrosion test apparatus whose temperature,pressure and velocity were controllable. The microstructure of the corrosion product film was analyzed with a scanning electron microscope. It was found that Cr5Mo alloy steel after surface nanocrystallization exhibited improved resistance against flow-accelerated-corrosion,and its corrosion product film was compact. However,the compactness and integrity of the corrosion product film on the steel after surface nanocrystallization decreased with the rise of shot peening impulse intensity,and the corrosion resistance of the nanocrystallized steel surface decreased therewith. Moreover,annealing treatment of the surface nanocrytallized alloy steel led to increase of corrosion rate; the corrosion rate tended to decline with elevating annealing temperature and to decline initially but rise later with extending temperature-holding time,while the nanocrystallized alloy steel exhibited the minimum corrosion rate after 2 h of annealing.