With the rapid development of high-strength low-alloy(HSLA)steel,Nb as an important microalloying element has received more and more attention in recent years.The application and behavior of Nb in HSLA steel,including...With the rapid development of high-strength low-alloy(HSLA)steel,Nb as an important microalloying element has received more and more attention in recent years.The application and behavior of Nb in HSLA steel,including microstructures optimization,refining grain size,and precipitation behavior of Nb-containing phases,were reviewed.Nb could play an important role in following manners:(1)Nb-containing phases promote ferrite formation,and Nb solute promotes bainite formation.(2)Nb solute atoms and Nb-containing phases can inhibit the growth of austenite grains and austenite recrystallization.(3)Nb(C,N)that precipitates in ferrite/bainite can provide more significant strengthening contribution(more than 300 MPa)than that in austenite(about 100 MPa).Some reasonable suggestions for the production of Nb-bearing HSLA steel with excellent mechanical properties were put forward.展开更多
In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and al...In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and aluminum deoxidization sequences. Thermodynamic calculations demonstrated that the complex inclusions with low melting point （harmless inclusions） are more favorable to be formed in condition that the melt was deoxidized using ferrosilicon first and then pure aluminum （Si/A1 deoxidization） than that deoxidized using pure aluminum first and then ferrosilicon （AI/Si deoxidization）. Al-rich inclusion decreases 83% from A1/Si deoxidization to Si/A1 deoxidization. The experimental results showed that the total quantity of inclusions decreases by 24% and the proportion of harmless inclusions is doubled when comparing Si/Al deoxidization with Al/Si deoxidization. The morphology of complex inclusion tends to be spherical, and the mean size is less than 5μm in condition of Si/Al deoxidization. The formation mechanism of harmless inclusions was discussed, and it is believed that the inclusions can be controlled reasonably in high aluminum steel using Si/Al deoxidization.展开更多
文摘With the rapid development of high-strength low-alloy(HSLA)steel,Nb as an important microalloying element has received more and more attention in recent years.The application and behavior of Nb in HSLA steel,including microstructures optimization,refining grain size,and precipitation behavior of Nb-containing phases,were reviewed.Nb could play an important role in following manners:(1)Nb-containing phases promote ferrite formation,and Nb solute promotes bainite formation.(2)Nb solute atoms and Nb-containing phases can inhibit the growth of austenite grains and austenite recrystallization.(3)Nb(C,N)that precipitates in ferrite/bainite can provide more significant strengthening contribution(more than 300 MPa)than that in austenite(about 100 MPa).Some reasonable suggestions for the production of Nb-bearing HSLA steel with excellent mechanical properties were put forward.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （No. U1460103）. Support was also provided by the Instrumental Analysis ＆ Research Center in Shanghai University.
文摘In order to reduce the negative effect of gross Al-rich inclusions on high aluminum steel, both thermodynamic calculations and designed deoxidization experiments were performed in condition of different silicon and aluminum deoxidization sequences. Thermodynamic calculations demonstrated that the complex inclusions with low melting point （harmless inclusions） are more favorable to be formed in condition that the melt was deoxidized using ferrosilicon first and then pure aluminum （Si/A1 deoxidization） than that deoxidized using pure aluminum first and then ferrosilicon （AI/Si deoxidization）. Al-rich inclusion decreases 83% from A1/Si deoxidization to Si/A1 deoxidization. The experimental results showed that the total quantity of inclusions decreases by 24% and the proportion of harmless inclusions is doubled when comparing Si/Al deoxidization with Al/Si deoxidization. The morphology of complex inclusion tends to be spherical, and the mean size is less than 5μm in condition of Si/Al deoxidization. The formation mechanism of harmless inclusions was discussed, and it is believed that the inclusions can be controlled reasonably in high aluminum steel using Si/Al deoxidization.
