The accurate prediction of damage behavior of welded components at high temperature is becoming incresasingly important in order to realize an optimised design and maintenance of a plant life.In the present paper,the ...The accurate prediction of damage behavior of welded components at high temperature is becoming incresasingly important in order to realize an optimised design and maintenance of a plant life.In the present paper,the creep properties of the weld of HK40 furnace tube are determined by means of a local deformation measuring technique.A damage mechanics approach is introduced to simulate the damage development and creep rupture of HK-40 furnace tubes due to the presence of a weld.Metallographical research also indicates that the weld has a higher damage rank.It has been illustrated that damage is prone to the weld in the later period of service life.It is thus concluded that the weldments may become the weak link in HK-40 furnace tubes.展开更多
本文在统计分析大量HK40性能数据基础上,提出了基于K-D法的HK40剩余寿命外推公式:t_r=exp(ā-10.36logσ+12000/T),其中的值:ā=(1/n)sum from l=1 to n(lnt_n-(42000/T_l)+10.36logσ_l)。公式物理意义明确,并得到良好验证。
Two types of carbides M23C6 and M7C3 precipitate orderly as carbon concentration in a high Cr-Ni austenitic steel increases during carburization process. The mathematical model that describes diffusion of carbon and t...Two types of carbides M23C6 and M7C3 precipitate orderly as carbon concentration in a high Cr-Ni austenitic steel increases during carburization process. The mathematical model that describes diffusion of carbon and the precipitation of M23C6 and M7C3 has been studied. A criterion to judge when the transformation of M23C6 to M7C3 is over and M7C3 precipitates directly has been given in simulated calculation. By applying the model, the carburization of HK40 steel has been calculated by means of finite difference computation techniques. The pack carburization tests for the HK40 steel have been carried out at 1273 K. The comparison between the experimental and the calculated results show acceptable agreement.展开更多
文摘The accurate prediction of damage behavior of welded components at high temperature is becoming incresasingly important in order to realize an optimised design and maintenance of a plant life.In the present paper,the creep properties of the weld of HK40 furnace tube are determined by means of a local deformation measuring technique.A damage mechanics approach is introduced to simulate the damage development and creep rupture of HK-40 furnace tubes due to the presence of a weld.Metallographical research also indicates that the weld has a higher damage rank.It has been illustrated that damage is prone to the weld in the later period of service life.It is thus concluded that the weldments may become the weak link in HK-40 furnace tubes.
文摘本文在统计分析大量HK40性能数据基础上,提出了基于K-D法的HK40剩余寿命外推公式:t_r=exp(ā-10.36logσ+12000/T),其中的值:ā=(1/n)sum from l=1 to n(lnt_n-(42000/T_l)+10.36logσ_l)。公式物理意义明确,并得到良好验证。
基金This work was supported by the National Natural Science Foundation of China under grant No.50071016.
文摘Two types of carbides M23C6 and M7C3 precipitate orderly as carbon concentration in a high Cr-Ni austenitic steel increases during carburization process. The mathematical model that describes diffusion of carbon and the precipitation of M23C6 and M7C3 has been studied. A criterion to judge when the transformation of M23C6 to M7C3 is over and M7C3 precipitates directly has been given in simulated calculation. By applying the model, the carburization of HK40 steel has been calculated by means of finite difference computation techniques. The pack carburization tests for the HK40 steel have been carried out at 1273 K. The comparison between the experimental and the calculated results show acceptable agreement.
