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    国产690TT合金U形管弯管区性能测定

    Determination of properties of domestic 690TT alloy U-shaped pipe in elbow area

    • 摘要: 对国产蒸汽发生器690TT合金U形管弯管区进行壁厚测量、金相检验、晶间腐蚀、应力腐蚀、残余应力测试等试验,并与直管区的性能进行对比。结果表明:国产蒸汽发生器690TT合金U形管弯管区外侧壁厚减薄最大为7.8%,弯管区的显微组织、晶粒大小及晶间腐蚀速率均与直管区相当。弯管后弯管区内侧表面残余应力为拉应力,外侧表面残余应力为压应力,消应力热处理后弯管区残余应力绝对值减小,不易发生应力腐蚀。采用弯管及消应力热处理可以使国产690TT合金U形管弯管区的各项性能满足使用要求。

       

      Abstract: Wall thickness measurement, metallographic examination, intergranular corrosion, stress corrosion and residual stress test were carried out on the elbow area of 690TT alloy U-shaped pipe of domestic steam generator, and the performance was compared with that of straight pipe section. The results show that the outer wall thickness of elbow area of 690TT alloy U-shaped pipe of domestic steam generator was thinned by 7.8%, the microstructure, grain size and intergranular corrosion rate of the elbow area were equivalent to those of the straight pipe area. After bending, the surface residual stress of the inner side of the elbow area was tensile stress and the surface residual stress of the outer side was compressive stress, after stress relieving heat treatment, the absolute value of residual stress in the elbow area decreased and the stress corrosion was not easy to occur. The properties of the elbow area of domestic 690TT alloy U-shaped pipe could meet the application requirements by using bend and stress relief heat treatment.

       

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