超超临界机组转子COST-FB2钢630℃长期时效稳定性研究  

Investigation on 630°C Long-Term Aging Stability for COST-FB2 Rotor Steel Used in Ultra-Supercritical Units

作　　者：姚汉新 江河[1] 姚志浩[1] 董建新[1] Yao Hanxin;Jiang He;Yao Zhihao;Dong Jianxin(University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学,北京100083

出　　处：《稀有金属材料与工程》2023年第4期1536-1542,共7页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51771016)。

摘　　要：以COST-FB2转子钢为研究对象,利用冲击试验、高温拉伸试验、硬度测试、扫描电镜、透射电镜及X射线衍射仪等测试方法研究了630℃长期时效中COST-FB2转子钢组织和性能的变化。结果表明:随着时效时间延长,冲击功、硬度和高温强度都呈下降趋势,冲击韧性在2000h后下降较为明显,后逐渐趋于稳定。硬度(HBW)总体处在较高水平(2479.4MPa),高温塑性未见明显变化。M_(23)C_(6)碳化物尺寸及含量有所增长,但未见明显粗化;Laves相尺寸增长更明显并在晶界处聚集,但未形成链状。Laves相的析出长大与聚集是导致冲击韧性下降的主要原因。研究结果认为630℃时效至5000 h COST-FB2钢能够保持较高的高温稳定性。In present work,the 630°C long-term aging stability(microstructure and properties)of COST-FB2 rotor steel were investigated by impact test,high temperature tensile test,hardness test in combine with SEM,TEM and XRD analysis.The investigation shows that impact energy,hardness and high temperature strength decrease with prolonging aging time.The impact toughness decreases apparently after aging for 2000 h and then keeps stable.The hardness(HBW)stays in a high level(2479.4 MPa),and the high temperature plasticity has no obvious change.The size and amount of M_(23)C_(6)carbide increases slightly during aging without apparent coarsen.The size of Laves phase increases more obvious and Laves phase tends to gather at grain boundary.While no chain of Laves phase is observed.The coarsen and gathering of Laves phase at grain boundary is the major reason for impact toughness degeneration.Bases on the research,it can be concluded that COST-FB2 rotor steel keeps stable at 630°C for up to 5000 h.

关 键 词：超超临界机组 转子钢COST-FB2 长期时效 M_(23)C_(6)碳化物 

分 类 号：TG142.24[一般工业技术—材料科学与工程] TG156.92[金属学及工艺—金属材料]