An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to impr...An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to improve productivity and energy saving without hampering the surface and mechanical property aspects of the material. Hot rolled coils annealed by slow cooling under insulated cover exhibit better ridging resistance than bell annealing treatment with a minor decrease in ductility. Soaking temperature prior to hot rolling has a significant effect on ridging resistance.展开更多
Refining process of 430 stainless steel in AOD （argon oxygen decarburization） was simulated under the experimental condition. Al was chosen as deoxidizer, Mg-Al alloy was added in process of refining, and slag used ...Refining process of 430 stainless steel in AOD （argon oxygen decarburization） was simulated under the experimental condition. Al was chosen as deoxidizer, Mg-Al alloy was added in process of refining, and slag used in oxidation period of AOD was chosen in the experiments. The variation of total oxygen content, the size, morphology and composition of inclusions in refining process and the mechanical properties, pitting corrosion resistance of final samples were studied. The results show that no obvious differences in total oxygen content were observed among all the experiments. Neither chain nor cluster Al_2O_3 inclusions were found in refining process of experiments treated by Mg-Al alloys, the average size of inclusions in the steel treated by Mg-Al alloys was less than that of inclusions in steel not treated by Mg-Al alloy. 430 stainless steel treated by Mg-Al alloy shows better tensile strength, yield strength, and pitting resistance than that in the contrast experiment.展开更多
A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-S...A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-Si-O system of 430 stainless steel melts at 1873 K. Further, the thermodynamic formation and transformation conditions of MgO · Al2O3 inclusion were discussed. The following results are obtained when ws, =0.26% and wo = 1.0 × 10^-5 in molten steel. The uniphase cordierite inclusion is difficult to exist stably; MgO· At203 inclusion cannot he formed in case of wAl being less than 1× 10^- 6 ; 3Al2O3 · 2SiO2 would change to MgO· Al2O3 and 2MgO · SiO2 in turn with increasing the Mg content when wAl is above 1.7× 10^- 6 ; with the formation of MgO · Al2O3 inclusion, A1 content increases with increasing Mg content when wMg is over 1. 7 × 10^- 9. For equilibrium condition and calculated steel composition, 2MgO·SiO2 inclusion would be formed ultimately and MgO · Al2O3 is almost inexistent.展开更多
The self-assembled monolayers （SAMs） of 1 tetradecylphosphonic acid （TDPA） formed on the 430 stain-less steel （SS430）were studied. Surface and morphological characterizations were studied by Fourier transformed ...The self-assembled monolayers （SAMs） of 1 tetradecylphosphonic acid （TDPA） formed on the 430 stain-less steel （SS430）were studied. Surface and morphological characterizations were studied by Fourier transformed in-frared spectroscopy （FTIR）, water contact angle measurement and atomic force microscopy （AFM）. And the elec-trochemical study on the corrosion inhihition of the SAMs was performed by polarization curve and electrochemical impedance spectroscopy （E1S） for evaluating the corrosion protection of the SAMs. The results show that TDPA was able to form a film spontaneously on the SS430 surface and the hydrophobic SAMs could protect SS430 from corrosion effectively. In addition, the oxide surface formed by the heat pretreatment could accelerate the rate of ad-sorption, but had little effect on improving the inhibition efficiency.展开更多
The self-assembly monolayers （SAMs） of n-dodecyltriethoxysilane （DTES） and 1 H, 1 H, 2H, 2H-perflu- orodecyltriethoxysilane （PFDS） on the surface of the 430 stainless steel （430SS） were prepared and their corr...The self-assembly monolayers （SAMs） of n-dodecyltriethoxysilane （DTES） and 1 H, 1 H, 2H, 2H-perflu- orodecyltriethoxysilane （PFDS） on the surface of the 430 stainless steel （430SS） were prepared and their corrosion protection performance was investigated by potentiodynamic polarization, Fourier transform infrared spectroscopy （FTIR） -attenuated total reflection （ATR）, static contact angle and atomic force microscopy （AFM）. The results showed that the alkali pretreatment and the water added into the self-assembly solution could generate more hydrox- yls on the 430SS surface, and then enhanced the adsorption of the SAMs. A suitable temperature of the self-assem- bly solution is important for the formation of the SAMs. The silane SAMs were chemically adsorbed on the 430SS substrates by Fe-O-Si bonds. In all cases tested, PFDS has a better inhibition effect compared with DTES, and the difference in inhibition effect is most marked at the lowest concentration of 1 mmol/L.展开更多
With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as...With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as well. This is attributed to the increasing role of the inhomogeneous nucleation by TiN particles during solidification. In addition, more fine precipitations of （Ti ,Nb）N are found in steel with increased carbon and nitrogen content.展开更多
文摘An approach to optimize the processing parameters to get superior ridging resistance and mechanical properties in commercial production of 430 ferritic stainless steel has been studied. Attention was also paid to improve productivity and energy saving without hampering the surface and mechanical property aspects of the material. Hot rolled coils annealed by slow cooling under insulated cover exhibit better ridging resistance than bell annealing treatment with a minor decrease in ductility. Soaking temperature prior to hot rolling has a significant effect on ridging resistance.
基金Sponsored by National Natural Science Foundation of China(50704010)Fundamental Research Funds for Central Universities of China(090402019)
文摘Refining process of 430 stainless steel in AOD （argon oxygen decarburization） was simulated under the experimental condition. Al was chosen as deoxidizer, Mg-Al alloy was added in process of refining, and slag used in oxidation period of AOD was chosen in the experiments. The variation of total oxygen content, the size, morphology and composition of inclusions in refining process and the mechanical properties, pitting corrosion resistance of final samples were studied. The results show that no obvious differences in total oxygen content were observed among all the experiments. Neither chain nor cluster Al_2O_3 inclusions were found in refining process of experiments treated by Mg-Al alloys, the average size of inclusions in the steel treated by Mg-Al alloys was less than that of inclusions in steel not treated by Mg-Al alloy. 430 stainless steel treated by Mg-Al alloy shows better tensile strength, yield strength, and pitting resistance than that in the contrast experiment.
基金Item Sponsored by National Natural Science Foundation of China (50704010)
文摘A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-Si-O system of 430 stainless steel melts at 1873 K. Further, the thermodynamic formation and transformation conditions of MgO · Al2O3 inclusion were discussed. The following results are obtained when ws, =0.26% and wo = 1.0 × 10^-5 in molten steel. The uniphase cordierite inclusion is difficult to exist stably; MgO· At203 inclusion cannot he formed in case of wAl being less than 1× 10^- 6 ; 3Al2O3 · 2SiO2 would change to MgO· Al2O3 and 2MgO · SiO2 in turn with increasing the Mg content when wAl is above 1.7× 10^- 6 ; with the formation of MgO · Al2O3 inclusion, A1 content increases with increasing Mg content when wMg is over 1. 7 × 10^- 9. For equilibrium condition and calculated steel composition, 2MgO·SiO2 inclusion would be formed ultimately and MgO · Al2O3 is almost inexistent.
文摘The self-assembled monolayers （SAMs） of 1 tetradecylphosphonic acid （TDPA） formed on the 430 stain-less steel （SS430）were studied. Surface and morphological characterizations were studied by Fourier transformed in-frared spectroscopy （FTIR）, water contact angle measurement and atomic force microscopy （AFM）. And the elec-trochemical study on the corrosion inhihition of the SAMs was performed by polarization curve and electrochemical impedance spectroscopy （E1S） for evaluating the corrosion protection of the SAMs. The results show that TDPA was able to form a film spontaneously on the SS430 surface and the hydrophobic SAMs could protect SS430 from corrosion effectively. In addition, the oxide surface formed by the heat pretreatment could accelerate the rate of ad-sorption, but had little effect on improving the inhibition efficiency.
文摘The self-assembly monolayers （SAMs） of n-dodecyltriethoxysilane （DTES） and 1 H, 1 H, 2H, 2H-perflu- orodecyltriethoxysilane （PFDS） on the surface of the 430 stainless steel （430SS） were prepared and their corrosion protection performance was investigated by potentiodynamic polarization, Fourier transform infrared spectroscopy （FTIR） -attenuated total reflection （ATR）, static contact angle and atomic force microscopy （AFM）. The results showed that the alkali pretreatment and the water added into the self-assembly solution could generate more hydrox- yls on the 430SS surface, and then enhanced the adsorption of the SAMs. A suitable temperature of the self-assem- bly solution is important for the formation of the SAMs. The silane SAMs were chemically adsorbed on the 430SS substrates by Fe-O-Si bonds. In all cases tested, PFDS has a better inhibition effect compared with DTES, and the difference in inhibition effect is most marked at the lowest concentration of 1 mmol/L.
基金this project by both the National Natural Science Foundation of China(NSF 50734002)and Baosteel is fully acknowledged.
文摘With the increase in the content of carbon, nitrogen and titanium in 430 ferritic stainless steel, the refinement of the solidification structure is obvious and the proportion of equiaxed grain increases remarkably as well. This is attributed to the increasing role of the inhomogeneous nucleation by TiN particles during solidification. In addition, more fine precipitations of （Ti ,Nb）N are found in steel with increased carbon and nitrogen content.
