尿素级316Lmod不锈钢管材的休氏腐蚀性能

Huey Corrosion Resistance for Urea Grade 316Lmod Stainless Steel Tube

采用休氏试验法研究了不同固溶热处理工艺对尿素级316Lmod不锈钢管材休氏腐蚀性能的影响,利用光学显微镜和扫描电镜观察了不同工艺热处理的试样在休氏试验过程中的表面腐蚀形貌,并分析了休氏试验的腐蚀机理。结果表明:在1000~1150℃下固溶热处理试样的平均腐蚀速率随固溶温度的升高而降低,而耐休氏腐蚀性能随固溶温度的升高而升高;随着腐蚀试验周期的增加,试样晶界的腐蚀坑数量增加,腐蚀坑面积增大,腐蚀速率也增大;随着固溶温度升高,相同腐蚀试验周期的试样晶界的腐蚀坑数量减少,腐蚀坑总面积也减少,耐休氏腐蚀性能提高。平均晶粒尺寸与固溶温度成正比,尺寸越大,材料耐非敏化态晶间腐蚀性能越好,耐休氏腐蚀性能也就越好。

The effect of different solution heat treatment processes on Huey corrosion properties of urea grade 316 Lmod stainless steel tube was studied by Huey test.The surface corrosion morphology of the specimens with different heat treatment processes during Huey test was observed by optical microscope and scanning electron microscope,and the corrosion mechanism of Huey test was analyzed.The results show that the average corrosion rates of the specimens solution heat treated at 1000-1150℃decrease with the increase of solution temperature,but the Huey corrosion resistance increases with the increase of solution temperature.With the increase of corrosion test cycle,the number of corrosion pits on grain boundaries of specimens,the area of corrosion pits and the corrosion rate increase.With the increase of solution temperature,the number of corrosion pits and the total area of corrosion pits on the grain boundary of specimens in the same corrosion test cycle decrease,and the Huey corrosion resistance improves.The average grain size is proportional to the solution temperature,the larger the average grain size is,the better the non sensitized intergranular corrosion resistance of the material is,and the better the Huey corrosion resistance is.