对高温运行78 000 h后的T91/G102异种钢焊接接头向火侧进行了常温拉伸、冲击、硬度和高温持久试验, 并对其进行了寿命估算。结果表明: 长时运行后, 接头两侧母材常温抗拉强度仍满足要求, 但焊接接头的常温抗拉强度已低于标准值; 两侧母材的冲击韧性仍较高, 但G102钢侧及T91钢侧熔合线处的冲击功最低; T91钢母材的显微硬度同运行前的基本相当, 而T91钢侧热影响区、焊缝、G102钢侧热影响区以及G102钢侧母材的显微硬度均明显降低; G102钢热影响区的高温蠕变性能最差; 焊接接头向火侧的剩余寿命为27 601 h, 但焊缝、热影响区性能的劣化将大大降低其安全运行可靠性; G102钢侧热影响区析出的碳化物与两侧母材析出的明显不同。

The mechanical properties of T91/G102 dissimilar steel welded joint on firey side after running for 78 000 h were investigated by room-temperature tensile test, impact test, micro-hardness test and high temperature stress rupture test, and lifespan estimate. The results show that the tensile strengths of the T91 and G102 steel base metals met the requirements, while the tensile strength of welded joint was below the standard value; The impact toughnesses of two base metals were high, but the lowest values were given by the fusion lines in both G102 and T91 steel side ; The micro-hardness of the T91 steel base metal was basically the same as that of a new one, but that of the heat affected zone, weld and G102 steel base metal decreased significantly after running for long times; The lowest value of high temperature stress rupture property was displayed in the heat affected zone on the G102 steel side. Life prediction indicated that the remaining life of the welded joint on firey side could last 27 601 hours. But due to the worse properties of the heat affected zone and the weld seam, the reliability of safe running would be greatly reduced; The type of carbide precipitated in the heat affected zone of the G102 steel side was different from that of the T91 and G102 steel base metals.