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利用多种分析手段深入分析了Inconel 690TT和Incoloy 800MA合金蒸汽发生器管材及其在高温高压水环境中的腐蚀行为.结果表明,沿管材厚度方向从内壁至外壁,Inconel 690TT合金管材S3晶界偏离理想晶界的程度逐渐增大,Kernel平均取向差(KAM)也逐渐增大,管材外壁为最薄弱区;Incoloy 800MA合金管材S3晶界偏离理想晶界的程度均匀,且主要集中于0~1°的小偏差范围内,KAM应变的变化也趋于平缓.溶氧的高温纯H2O中,Inconel 690TT合金表面腐蚀产物为双层膜结构,外层为富Fe尖晶石与Ni O小颗粒,内层膜为Ni O相且疏松多孔,不能对基体起到良好的保护作用,局部区域腐蚀深度可达716 nm;Incoloy 800MA合金表面腐蚀产物为双层膜结构,外层为大颗粒状尖晶石相,内层膜为小颗粒尖晶石相,Cr在内层膜与基体的界面富集,平均腐蚀深度仅约为150 nm.相同条件下,溶氧的高温纯H2O中Incoloy 800MA合金的内层膜厚度显著小于Inconel 690TT合金.因此,在溶氧高温高压纯H2O环境中,Cr发生溶解,Incoloy 800MA合金比Inconel 690TT合金耐蚀性更优.
The corrosion behaviors of Inconel 690TT and Incoloy 800MA alloy steam generator tubes and their corrosion behavior in high temperature and high pressure water environment were analyzed in detail by various means of analysis.The results show that the deviation of the grain boundaries of Inconel 690TT alloy pipe S3 from the inner wall to the outer wall along the pipe thickness The degree of ideal grain boundary gradually increases, Kernel average orientation difference (KAM) also increases gradually, and the outer wall of pipe is the weakest area. Incoloy 800MA alloy pipe has a uniform grain boundary deviating from the ideal grain boundary and mainly concentrates in 0-1 °, the KAM strain changes also tend to be gentle.In the high temperature pure H2O, the corrosion products of Inconel 690TT alloy are bilayer membrane structure, the outer layer is Fe-rich spinel and NiO small particles, The inner film is Ni O phase and loose porous, can not play a good protective effect on the substrate, the corrosion depth of the local region up to 716 nm; Incoloy 800MA alloy surface corrosion product is a bilayer membrane structure, the outer layer of large granular spinel And the inner film is small spinel phase. Cr is enriched at the interface of the inner film and the matrix, and the average depth of corrosion is only about 150 nm. Under the same conditions, high temperature pure H2O in dissolved oxygen, Incoloy 800MA alloy Thickness of the inner membrane was significant Less than Inconel 690TT alloy. Thus, the high temperature high pressure pure oxygen environment H2O, Cr dissolves, Incoloy 800MA alloy better in corrosion resistance than the alloy Inconel 690TT.