Precipitationstudy on Ti-Nb-Mo contained high strength steels
Steels with the yield strength higher than 700 MPa have been achieved through Ti,Nb and Mo microalloying technique and TMCP process.The high strength is greatly attributable to the nano-sized Ti,Nb and Mo precipitates.In this work,Thermo-calc software was employed to calculate the thermodynamic equilibrium phases.The morphology,distribution,size and component changes of Ti,Nb and Mo precipitates in cast slabs and hot-rolled plates were studied using SEM and TEM,respectively.It was found that after hot-rolling,precipitates with diameter (D) larger than 120 nm grew bigger and those with D between 40 to 120nm dissolved partially and downsized.The number of the precipitate smaller than 10nm increases obviously after hot-rolling.Most of the precipitates are composed with Ti,Nb and Mo carbides.It was observed that the content of Mo became higher in carbides with the size of the precipitates decreasing.In summary,TMCP process has different influences on different sizes of precipitates.Through precise temperature controlling of TMCP process,the size and the distribution of precipitates can be controlled and therefore,different strength level can be achieved.
high strength steels microalloying technique nano-sized precipitates
CAI Ning JU Xin-hua LIU Wei-ping
Shougang technical research institute,Beijing 100043,China
国际会议
Asia Steel International conference 2012(第五届亚洲钢铁大会)
北京
英文
1-4
2012-09-23（万方平台首次上网日期，不代表论文的发表时间）