回火温度对20Cr13不锈钢液固两相流冲刷腐蚀性能的影响

Effect of Tempering Temperature on Erosion-Corrosion Performance of 20Cr13 Stainless Steels in LiquidSolid Two Phase Flow

对20Cr13不锈钢经过1 030℃淬火后在不同温度下进行回火处理,分析了回火温度对20Cr13不锈钢组织硬度的影响,采用自制的旋转冲刷腐蚀试验机研究了在0.5M H2SO4液固两相流条件下,回火温度对20Cr13不锈钢冲刷腐蚀性能的影响,利用扫描电镜观察了试样冲刷腐蚀表面的微观形貌,探讨了其冲刷腐蚀机理.结果表明:20Cr13不锈钢经淬火后250℃左右回火时硬度最高;经回火处理后20Cr13不锈钢冲刷腐蚀特征表现为腐蚀作用强于冲刷作用,而冲刷强烈促进腐蚀,冲刷与腐蚀的交互作用占冲刷腐蚀总失重率的80%左右.随着回火温度的升高,20Cr13不锈钢组织由马氏体转变为屈氏体、索氏体,碳化物颗粒逐渐长大,腐蚀量增大,冲刷腐蚀总量也增大,250℃左右回火时,20Cr13不锈钢抗冲刷腐蚀性能最佳.

20Cr13 stainless steel was quenched at 1 030 ℃ and then tempered at different temperatures. Effect of tempering temperature on the microstructure and hardness was analyzed. Erosion-corrosion(E-C) performance of 20Cr13 stainless steel in 0.5M H2SO4 slurry containing silica particles was studied by using a home-made rotary erosion wear tester. The morphologies of the worn surfaces of the samples after E-C test were observed using scanning electron microscope(SEM), and E-C mechanisms were discussed. The results showed that the hardness of 20Cr13 stainless steel had the maximum value at tempering temperature of near 250 ℃.The characteristics of E-C for 20Cr13 stainless steel at different tempering temperatures were as follows: pure corrosion action was larger than pure erosion(wear),and at the same time erosion strongly promoted corrosion. The synergistic rate between erosion and corrosion accounted for about 80% of the total E-C rate. With the increase of tempering temperature, the microstructure of 20Cr13 stainless steel changed from martensite to troostite and sorbite, the carbides gradually grew, the corrosion rate increased, and the total E-C rate also increased. It was found that 20Cr13 stainless steel displayed the most excellent E-C resistance near 250 ℃ tempering.