Damage prediction of HP40Nb steel with coupled creep and carburization based on the continuum damage mechanics  

作　　者：Limin SHEN Jianming GONG Yong JIANG Luyang GENG 

机构地区：[1]College of Mechanical and Power Engineering,Nanjing University of Technology,Nanjing 210009,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2012年第4期279-286,共8页金属学报（英文版）

基　　金：the support of National Natural Science Foundation of China (No. 50775107);National High Technical Research and Development Programme of China (No. 2007AA04Z407);Innovation Program for Graduate Students in Nanjing University of Technology (No. BSCX200816)

摘　　要：HP40Nb steel, used as a candidate material for ethylene cracking furnace tube, suffers creep and carburization damage from the complex environment of high temperature, high carbon potential and low oxygen partial pressure, and they lead to failure of the furnace tubes ahead of designed life. In order to investigate damage evolution under the complex condition, coupled creep damage and carburization damage constitutive equations were developed according to continuum damage mechanics theory. Based on the finite element ABAQUS code, user subroutines were developed for analyz- ing damage evolution of ethylene furnace tube under the action of coupled creep- carburization. The results show that carburization accelerates the damage process dramatically, damage value reaches the critical value along the inner surface after serving for 75,000 h under the action of creep-carburization, meanwhile the damage value is only 0.53 along the outer surface after operating the same time under the action of creep alone, which means that microcracks are generated along the inner surface under the action of coupled creep-carburization, fracture begins along the outer surface of tube under the action of creep alone.HP40Nb steel, used as a candidate material for ethylene cracking furnace tube, suffers creep and carburization damage from the complex environment of high temperature, high carbon potential and low oxygen partial pressure, and they lead to failure of the furnace tubes ahead of designed life. In order to investigate damage evolution under the complex condition, coupled creep damage and carburization damage constitutive equations were developed according to continuum damage mechanics theory. Based on the finite element ABAQUS code, user subroutines were developed for analyz- ing damage evolution of ethylene furnace tube under the action of coupled creep- carburization. The results show that carburization accelerates the damage process dramatically, damage value reaches the critical value along the inner surface after serving for 75,000 h under the action of creep-carburization, meanwhile the damage value is only 0.53 along the outer surface after operating the same time under the action of creep alone, which means that microcracks are generated along the inner surface under the action of coupled creep-carburization, fracture begins along the outer surface of tube under the action of creep alone.

关 键 词：Damage prediction HP40Nb Coupled creep-carburizationEthylene furnace tube 

分 类 号：O346.5[理学—固体力学] TG161[理学—力学]