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用TIG法对K9合金涡轮叶片叶冠作耐磨堆焊时,依靠采用适当予热、小的焊接电流和断续施焊等工艺措施解决了焊接热裂纹。在此基础上,本文试验了焊前、焊后高温热处理对应变—时效裂纹的影响,并对影响的机理作了一定探讨。结果表明,焊后高温热处理应以尽可能快的加热速度越过K9合金的时效温度范围(760～920℃),在该温度区间停留时间越长,则应变一时效裂纹越严重。焊前进行1080℃/4小时、空冷的超时效热处理,可使沉淀强化相γ’长大,改善了合金的室、高温塑性,减少了焊接过程中热影响区γ’的溶解,从而降低了合金应变—时效裂纹敏感性。试验还表明,对K9合金叶片叶冠堆焊,必须同时采用焊前超时效热处理和焊后快速加热的高温热处理,才能避免在热影响区出现应变—时效裂纹,文中给出了避免出现裂纹的热处理制度。
TIG method for K9 alloy turbine blade crown for wear-resistant surfacing, relying on the use of appropriate preheat, a small welding current and intermittent welding process measures to solve the welding hot cracking. On this basis, this paper tests the effect of pre-weld and post-weld high temperature heat treatment on the strain-aging crack, and discusses the influencing mechanism. The results show that the high temperature heat treatment after welding should cross the aging temperature range of K9 alloy (760-920 ℃) with the heating speed as fast as possible. The longer the residence time in this temperature range, the more severe the strain-aging crack. The temperature of 1080 ℃ for 4 hours and the air-cooling time-out heat treatment before welding can increase the γ ’of precipitated strengthening phase, improve the room and high-temperature plasticity of the alloy and reduce the dissolution of γ’ in the heat affected zone during welding, Alloy Strain - Aging Crack Sensitivity. The experiment also shows that for the surfacing of K9 alloy blade crown, it is necessary to use both the high temperature heat treatment before welding and the high temperature heat treatment after welding to avoid the occurrence of strain-aging cracks in the heat-affected zone. In this paper, Heat treatment system.