700℃先进超超临界机组末级过热器用新型镍铁基高温合金的组织与性能

Microstructure and Properties of Ni-Fe-base Superalloy for 700℃ Advanced Ultra Supercritical Unit Final Superheater

研究了700℃先进超超临界(A-USC)机组末级过热器用新型镍铁基HT700T高温合金的组织和性能。结果表明:HT700T合金为析出强化型合金,在750℃的组织稳定性较好;合金在750℃时的屈服强度为598 MPa,且热暴露3000 h后其屈服强度仍约为400 MPa;合金在750℃/105h的持久强度为103 MPa;在750℃热暴露104h后,室温冲击功为50 J·cm-2,较热暴露前的略有下降;合金的750℃抗蒸汽氧化性能达到完全抗氧化级,在750℃/2×105h模拟烟灰/烟气条件下的金属腐蚀深度约为0.2 mm;HT700T合金的综合性能基本满足700℃A-USC机组末级过热器的服役性能要求,其工业试制锅炉管已在试验平台上正常运行超过15000 h。

The microstructure and properties of a new Ni-Fe-base HT700 T superalloy for 700℃A-USC unit final superheater were studied.The results show that HT700 T alloy was a precipitation-hardening alloy,and the microstructure stability of HT700 T alloy at 750℃was stable.The yield strength at 750℃was 598 MPa,and remained about 400 MPa after thermal exposure for 3000 h.The creep rupture strength of the alloy at 750℃/105 h was 103 MPa.The impact energy at room temperature of the alloy after thermal exposure at 750℃for 104 h was 50 J·cm-2,which was slightly lower than that before thermal exposure.The resistance to steam oxidation at 750℃reached the complete oxidation resistance level,and the metal corrosion thickness in simulated flue gas and coal ash at 750℃/2×105 h was 0.2 mm.The comprehensive performance of HT700 T alloy could basically meet the service performance requirements of 700℃A-USC unit final superheater;the industrial manufactured alloy boiler tube had been running normally on the test platform for over 15000 h.