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托克托电厂一期工程 1号机组末级过热器管排 ,采用了SA2 13-T91钢制造。该钢可焊性差 ,空淬倾向大 ,快速冷却容易产生冷裂纹 ,冷却速度过慢会使综合机械性能下降。因此 ,该钢的焊接工艺和过程控制非常重要。其焊接工艺为预热温度小于 4 5 0℃ ,在冬季 ,预热温度 2 0 0～ 2 5 0℃的效果良好 ;层间温度为 2 5 0～ 35 0℃ ;热处理为经 10 5 0℃正火与 74 0～ 76 0℃回火 ,1h的回火恒温时间 ;升、降温速度小于 15 0℃ /h。为保证焊缝的质量 ,施工中进行了严格的过程控制。这包括焊前做准备工作 ;制订可靠的焊接和充氩方案 ;制订并遵守适当的作业程序、方法和内容等。施工中由于焊接工艺得当 ,过程控制严格 ,使T91钢小径管焊缝获得良好的焊接组织及优良的机械性能 ,保证了机组的正常运转 ,提高了机组运行的可靠性和稳定性
Tuoketuo Power Plant No. 1 unit of the first stage superheater tube row, using SA2 13-T91 steel manufacturing. The steel is poor weldability, air quenching tend to be large, rapid cooling prone to cold cracking, slow cooling will make the overall mechanical properties decline. Therefore, the steel welding process and process control is very important. The welding process is preheating temperature is less than 450 ℃, in winter, the preheating temperature of 200 ~ 250 ℃ good effect; interlayer temperature of 250 ~ 35 0 ℃; heat treatment by 105 ℃ Normalizing and tempering 74 0 ~ 76 0 ℃, 1h tempering constant temperature; l, cooling rate is less than 15 0 ℃ / h. In order to ensure the quality of the weld, the construction of a rigorous process control. This includes preparation before welding; development of reliable welding and argon filling programs; development and adherence to appropriate operating procedures, methods and contents. Due to the proper welding process and strict process control during construction, the weld of T91 steel small-diameter pipe has good welding structure and excellent mechanical performance, which ensures the normal operation of the unit and improves the reliability and stability of the unit operation