2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS w...2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS was first aged at different temperatures and periods of time for drawing the time-temperature-transformation profiles. The results identified the main precipitates as σ phase, with nose temperature of about 950℃. Also, 2707 specimen was aged at 950℃ for a short time, and the morphology, distribution and amount of σ phase were examined through the scanning electron microscope and X-ray diffraction,σ phase was initially formed at the boundaries of ferrite and austenite and then transformed through the eutectoid reaction (α→σ+γ2). Finally, the precipitation and growth of σ phase in 2707 steels aged at nose temperature for a short period reduced the corrosion resistance and deteriorated the mechanical properties, and the corresponding reason was further analyzed.展开更多
Effects of compression deformation on the sigma-phase precipitation behavior of B-containing S31254 stainless steel after solution treatment were studied using the Gleeble compression test. The cold and hot processing...Effects of compression deformation on the sigma-phase precipitation behavior of B-containing S31254 stainless steel after solution treatment were studied using the Gleeble compression test. The cold and hot processing characteristics of B-containing S31254 stainless steel were evaluated, and the results show that the speed of compression deformation increased the precipitation rate of the sigma phase, and the location of precipitation extended from the austenite grain boundary to the original hot rolling deformation area. During cold deformation at room temperature, the precipitation rate increased when the deformation reached at 40%. Deformation at 950℃ affected precipitation more obviously. At 1074 ℃, when the deformation reached 20%, the precipitated phases started increasing, and above this deformation range, precipitation began decreasing. Also, at 1074℃ the deformation accelerated the precipitation of sigma phase;but with deformation, there was a change in critical temperature for the sigma-phase excursion. The precipitation position of the sigma phase is strongly related to the area of the original hot rolling deformation. With an increase in the deformation amount, precipitates in this region appeared as coarse-grained, skeletal, and network-like features.展开更多
基金National Natural Science Foundation of China (Grant No. 51371123)Shanxi Province Science Foundation for Youths (201601D202033).
文摘2707 hyper-duplex stainless steels (HDSSs) contain high contents of alloying elements (Cr, Ni, Mo and N), which may shorten the incubation period and promote both nucleation and growth of sigma (σ) phase. 2707 HDSS was first aged at different temperatures and periods of time for drawing the time-temperature-transformation profiles. The results identified the main precipitates as σ phase, with nose temperature of about 950℃. Also, 2707 specimen was aged at 950℃ for a short time, and the morphology, distribution and amount of σ phase were examined through the scanning electron microscope and X-ray diffraction,σ phase was initially formed at the boundaries of ferrite and austenite and then transformed through the eutectoid reaction (α→σ+γ2). Finally, the precipitation and growth of σ phase in 2707 steels aged at nose temperature for a short period reduced the corrosion resistance and deteriorated the mechanical properties, and the corresponding reason was further analyzed.
基金The present work was financially supported by National Natural Science Foundation of China (Grant No. 51371123)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 2013140211003)+1 种基金Shanxi Natural Science Foundation Project (Grant Nos. 2014011002-1, 201601D202033, 201601D202034)Innovation Project for Graduate Education of Shanxi province (Grant No. 2016JD20).
文摘Effects of compression deformation on the sigma-phase precipitation behavior of B-containing S31254 stainless steel after solution treatment were studied using the Gleeble compression test. The cold and hot processing characteristics of B-containing S31254 stainless steel were evaluated, and the results show that the speed of compression deformation increased the precipitation rate of the sigma phase, and the location of precipitation extended from the austenite grain boundary to the original hot rolling deformation area. During cold deformation at room temperature, the precipitation rate increased when the deformation reached at 40%. Deformation at 950℃ affected precipitation more obviously. At 1074 ℃, when the deformation reached 20%, the precipitated phases started increasing, and above this deformation range, precipitation began decreasing. Also, at 1074℃ the deformation accelerated the precipitation of sigma phase;but with deformation, there was a change in critical temperature for the sigma-phase excursion. The precipitation position of the sigma phase is strongly related to the area of the original hot rolling deformation. With an increase in the deformation amount, precipitates in this region appeared as coarse-grained, skeletal, and network-like features.
