HR3C耐热钢650℃持久性能与断裂行为  

Creep rupture property and fracture behavior of HR3C heat-resistant steel at 650 ℃

作　　者：黄竹平[1] 胡正飞[1] 王起江[2] 刘偲展[1] 

机构地区：[1]同济大学材料科学与工程学院,上海200092 [2]宝钢研究院,上海201900

出　　处：《材料热处理学报》2013年第11期61-66,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然基金项目资助项目(50871076)

摘　　要：在650℃下对国产HR3C耐热钢进行了标准拉伸持久试验,采用外推法计算出该钢105h的持久强度极限达到104.98MPa。不同持久时间的样品硬度测试表明,随着持久时间增加,硬度上升,且晶界硬度高于晶内硬度。在持久时间2000 h左右达到峰值后开始缓慢下降,晶界和晶内硬度发生反转。断口观察显示,持久断裂的形态主要是沿晶断裂形态。利用SEM和EDS等对不同应力状态下的蠕变断裂试样微观组织进行了分析比较,随着持久时间的增加,耐热钢中析出相不断析出和长大,晶内析出细小弥散分布的NiCrN,起到显著的沉淀强化作用;晶界随持久时间延长明显宽化,准连续分布于晶界的主要碳化物M23C6长大速度快,明显降低晶界强度而弱化晶界表现出晶界脆化倾向,成为蠕变空洞形核地点。For exploring stress rupture properties and fracture behavior of HR3C heat-resistant steel （HRS）, standard creep-rupture tests for the HR3C steel were conducted at 650 ℃ The creep rupture strength at 650 ℃ was determined by extrapolation method to be 650 - O＇105 104.98 MPa. Microhardness of the steel increases with lasting time and comes to the peak around 2000 h, and the value at grain boundary is higher than that in the matrix. With prolonging time, hardnesses at grain boundary and in the matrix decrease slowly and their values reverse. SEM observation shows that the fractographs exhibit mainly intergranular fracture. Meanwhile microstructure investigations reveal that with prolonging the lasting time, the second phases are precipitated and grown continuously. The fine NbCrN particles are precipitated dispersively in the matrix with distinctly strengthening effect~ However, M23 C6 carbides precipitated along grain boundaries guasi- continuously grow much fast and widen the grain boundaries, which obviously weaken the grain boundaries strength and show an obvious effect of embrittlement tendency with the increase of lasting time. Plenty of coarsening carbides residing at the grain boundary tend to be the nucleation sites for creep voids.

关 键 词：HR3C耐热钢 持久性能 析出相 

分 类 号：TG142.73[一般工业技术—材料科学与工程]