GH984G合金管高温持久性能及组织稳定性研究

Creep rupture properties and microstructure stability of GH984G alloy tube

GH984G合金是我国650~700℃超超临界燃煤发电机组的重要候选材料。研究了GH984G合金管700℃高温持久性能及对应温度下的组织稳定性。结果表明,GH984G合金管的700℃持久性能优异,10~5 h的外推持久强度为153.8 MPa,能够很好满足电站用高温材料持久性能的要求。在700℃经历长期时效后,随着时间延长,晶界碳化物逐渐粗化,基体上的γ′相粒径逐渐粗化但保持球状并呈均匀弥散分布,在700℃下时效长达19 144 h仍未发现有害相析出。良好的组织稳定性保障了GH984G合金管的700℃持久性能。

GH984 G alloy is an important candidate material for 650~700 ℃ ultra-supercritical coal-fired generating units.Creep rupture properties and microstructure stability of GH984 G alloy tube are studied.The results show that 700 ℃ creep rupture properties is excellent,and the extrapolated strength of 10~5 h is 153.8 MPa,which can meet the requirements of long-term performance of high temperature materials for power stations.After aging at 700 ℃,which the extension of time,the grain boundary carbides gradually coarsen,the particle size of the γ′ phase on the matrix gradually coarsens but its spherical morphology remains with distributing uniformly.However,no harmful phase precipitates even ageing at 700 ℃ for up to 19 144 h.Excellent microstructure stability guarantees the 700 ℃ creep rupture properties of the GH984 G alloy tube.