Inconel 625合金在富氧高温熔渣中的腐蚀行为

Corrosion behavior of inconel 625 alloy in the oxygen-rich and high-temperature slag

针对镍顶吹熔炼喷枪使用寿命低的问题,以Inconel 625合金为替代材料,采用挂片试验,研究了该合金在氧气流量为15000~42000 Nm^(3)/h,熔渣温度1400℃下的腐蚀行为及机理.采用金相显微镜、扫描电镜、能谱仪、电子探针及显微硬度计等分析了试样的组织形貌、元素分布及硬度.结果表明:15~20 h时Cr_(2)O_(3)等氧化膜的形成阻碍了氧化腐蚀的进行;合金的严重腐蚀区域发生在表面0~250μm,250~1650μm为热影响区;富Nb贫Cr区优先被腐蚀,随着由Cr_(2)O_(3)、Fe_(2)O_(3)、Cr_(2)S_(3)、Nb_(0.1)Ni_(0.9)、[Mg、Fe]_(2)SiO_(4)等构成的复杂氧化膜体系的不断形成与分解,合金中各主要元素不断腐蚀脱落,且氧化膜中的Mg、S元素来源于熔渣;腐蚀后的合金表面硬度明显降低.

In order to solve the problem of low service life of spray gun for nickel top-blown smelting,Inconel 625 alloy was used as a substitute material,corrosion behavior and mechanism of Inconel 625 alloy were studied under actual working conditions:oxygen flow rate 15000~42000 Nm^(3)/h and slag temperature 1400℃.The microstructure,element distribution and hardness of the samples were analyzed by OM,SEM,EDS,EMPA and micro-hardness tester.The results showed that the formation of oxide film such as Cr_(2)O_(3)oxide hindered the corrosion process during 15~20 h.The severe corrosion zone of the alloy occur in 0μm to 250μm on the surface,and the heat-affected zone is in 250~1650μm.Nb-rich and Cr-poor areas are corroded first.With the continuous formation and decomposition of the complex oxide film system composed of Cr_(2)O_(3),Fe_(2)O_(3),Cr_(2)S_(3),Nb_(0.1)Ni_(0.9),[Mg,Fe]_(2)SiO_(4),the main elements in the alloy are corroded off,and Mg and S elements in the oxide film are derived from slag.The hardness of the corroded alloy surface decrease obviously.