High-temperature short-time tensile stress ruture strength prediction of C-HRA-5 steel welded joint

C-HRA-5钢焊接接头高温短时拉伸及持久强度预测 High-temperature short-time tensile stress ruture strength prediction of C-HRA-5 steel welded joint 张肖龙 ZHANG Xiaolong 1 first-author 杜华云 DU Huayun 1 corresp duhuayun@tyut.edu.cn 卫英慧 WEI Yinghui 1 侯利锋 HOU Lifeng 1 太原理工大学材料科学与工程学院 太原理工大学材料科学与工程学院 College of Materials Science and Engineering, Taiyuan University of Technology College of Materials Science and Engineering, Taiyuan University of Technology 持久强度对于评价C-HRA-5钢焊接接头在复杂工况条件下的使用寿命具有极其重要的意义。通过不同温度下的高温短时拉伸试验,基于Larson-Miller参数,利用状态函数和全微分的特征,建立了C-HRA-5钢焊接接头持久强度预测的数学模型,外推10万小时的持久强度。结果表明:C-HRA-5钢焊接接头在650℃时强度和塑性最好,在700℃时呈现典型的微孔聚集性断裂,随着温度的升高,第二相颗粒和夹杂物增多,位错的塞积群增多,焊接接头的力学性能降低。700℃时外推拟合公式为lgσ=2.760 18-0.131 51 lgτ,外推10万小时的持久强度为σ 10 5 973 =116.020 3 MPa,高于ASME SA-213标准的要求。 The stress rupture strength is of great significance to evaluate the service life of the C-HRA-5 welded joint under complex working conditions. A mathematical model was established to predict the stress rupture strength based on the LarsonMiller（L-M） parameter formula through the high-temperature short-time tensile test at different temperatures, and the stress rupture strength of 100 000 hours was extrapolated. The results show that the welded joint of C-HRA-5 steel represents the best strength and plasticity at 650 ℃ at all service temperatures, and presents typical micropore aggregation fracture at 700 ℃. With the increase of temperature, the second phase precipitates in-crease, the dislocation pile-up increases, and the mechanical properties of the welded joint decrease. Based on L-M parameters and the characteristics of state function and total differential, a mathematical model is established to predict the stress rupture strength of C-HRA-5 steel welded joints. The extrapolated fitting formula is lgσ =2.760 18-0.131 51 lgτ at 700 ℃ and the lasting strength of 100 000 hours is σ 10 5 973 =116.020 3 MPa, higher than ASME SA-213 standard. C-HRA-5钢 持久强度 Larson-Miller 位错塞积 C-HRA-5 steel stress rupture strength Larson-Miller dislocation pile-up TG407 山西省自然科学基金资助项目（201801D121090） 2022-03-08 9 51