12%Cr马氏体钢焊缝金属45000h高温服役老化分析  

Microstructural evolution of 12%Cr martensite steel weld joint at high temperature for 45000hours service

作　　者：陈德龙 王弘喆[2] 候淑芳 梁法光[2] 王军刚[2] 

机构地区：[1]国电泰州发电有限公司,江苏泰州225327 [2]西安热工研究院有限公司,陕西西安710032

出　　处：《热力发电》2014年第1期69-73,共5页Thermal Power Generation

摘　　要：通过金相、碳复型萃取、投射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线能谱(EDS)等方法对600℃服役约45 000h的12%Cr马氏体钢焊缝金属的显微组织结构进行了分析,研究影响12%Cr马氏体钢高温服役退化的因素。结果表明,该12%Cr马氏体钢焊缝金属的组织结构较服役前发生很大变化:(1)大量Laves相在晶界和板条界沉淀析出呈链状分布;(2)M23C6型碳化物发生粗化;(3)Z相以消耗MX为代价在晶界和亚晶界沉淀析出。沉淀相粗化导致强化效果下降,阻止亚晶长大的能力下降。Aiming at finding out the relationship between microstruetural evolution and degrada- tion of creep rupture strength,the microstructural evolution of the weld joint metal 12%Cr mar- tensite steel used for superheater header after 45 000 hours service at 600 ℃ has been investiga- ted,by means of carbon replica extraction method, transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS）. The results show that, the microstructure of weld joint metal 12%Cr martensite steel after 45 000 hours service at high temperature changed significant- ly： （1） the Laves phase precipitated along the martensite lath boundaries and the prior austenite grain boundaries;（2） the M2BC6 carbides coarsened; （3） the Z phase formatted around the prior austenite grain boundaries and the packet boundaries by consuming the MX carbonitrides. Coarsen of the precipitated phase resulted in decrease in strengthening effect and inhibiting ability for sub- grain＇s growth. Furthermore,the precipitation of Z phase consumed large amount of MX carboni- trides,causing the tempering martensite recovered and the subgrain structure coarsened,which af- fected the high temperature creep rupture strength of the 12%Cr martensite steel seriously.

关 键 词：12%Cr马氏体钢 焊缝 高温蠕变 服役退化 LAVES相 Z相 

分 类 号：TG142.1[一般工业技术—材料科学与工程]