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针对大坝电厂汽轮机顶盖主汽门大型耐热铸钢件出现的裂纹,传统焊接方法会造成焊缝金属稀释母材合金元素,导致焊缝及热影响区抗高温氧化性差,难以得到预期目的。经过多次试验,总结出采用镍基焊条焊接隔离层、用奥氏体焊条填充和盖面的冷焊方法,有效的避免了母材金属铬钼元素的稀释,保证了焊缝金属的抗高温氧化性,保障机组快速恢复运行。
In view of the cracks in the large heat-resistant cast steel of the main steam valve roof of the dam in the Dapar power plant, the conventional welding method will cause the weld metal to dilute the base metal alloying elements, resulting in poor high temperature oxidation resistance of the weld and the heat affected zone and failing to achieve the expected purpose . After several tests, it is concluded that the nickel-based electrode welding insulation layer, filled with austenitic electrode and cover the cold welding method, effectively avoiding the base metal chromium and molybdenum dilution, to ensure that the weld metal high temperature Oxidation, to ensure rapid recovery unit operation.