Through the thermo-mechanical control process （TMCP）, a high Nb low Mo fire resistant steel with the yield strength （YS） of 521 MPa at room temperature （RT） and 360 MPa at elevated temperature （ET） of 600 ℃ w...Through the thermo-mechanical control process （TMCP）, a high Nb low Mo fire resistant steel with the yield strength （YS） of 521 MPa at room temperature （RT） and 360 MPa at elevated temperature （ET） of 600 ℃ was developed based on MX （M=Nb, V, Mo; X=C,N） precipitation strengthening. A series of tensile and con- stant load tests were conducted to study the mechanical properties at ET. The dynamic continuous cooling transfor- mation （CCT） as well as precipitation behavior of microalloy carbonitride was investigated by means of thermal sim- ulator and electron microscopy approaches. Results showed that the failure temperature of tested steel was deter- mined as 653 ℃, and the granular bainite was obtained when the cooling rate was higher than 10 ℃/s. In the rolled state, a certain amount of M/A islands was observed. During heating from RT to ET, M/A islands disappeared, and cementites and high dense compound precipitates （Nb, Mo, V）C with size of less than 10 nm precipitated in ferrite at ET （600 ℃）, which resulted in precipitation strengthening at ET.展开更多
The nano-concentrates and flame retardant nano-coating were prepared in thhis study. The effect of nano-SiO2 on the corrosion resistance and fire resistance of ammonium polyphosphate-pentaerythritol-melamine （APP- PE...The nano-concentrates and flame retardant nano-coating were prepared in thhis study. The effect of nano-SiO2 on the corrosion resistance and fire resistance of ammonium polyphosphate-pentaerythritol-melamine （APP- PER-MEL） coating was investigated by differential thermal analysis （DTA）, scanning electron microscopy （SEM）, effective thermal conductivity （λ/d）, X-ray photoelectron spectroscopy （XPS） and fire protection test. The chemical action and endothermic effect of ammonium polyphosphate, pentaerythritol and melamine in traditional flame retardant coating were damaged by salt spray condition, whereas the flame-retardant additives in the nano-coating demonstrated the good chemical interaction in salt spray condition. The uniformly dispersed nano-SiO2 particles could improve corrosion resistance of the coating, and hence nano-coating could remain the good fire-resistant properties even after 500 h salt spray test.展开更多
基金Item Sponsored by National Basic Research Program of China(2010CB630805)
文摘Through the thermo-mechanical control process （TMCP）, a high Nb low Mo fire resistant steel with the yield strength （YS） of 521 MPa at room temperature （RT） and 360 MPa at elevated temperature （ET） of 600 ℃ was developed based on MX （M=Nb, V, Mo; X=C,N） precipitation strengthening. A series of tensile and con- stant load tests were conducted to study the mechanical properties at ET. The dynamic continuous cooling transfor- mation （CCT） as well as precipitation behavior of microalloy carbonitride was investigated by means of thermal sim- ulator and electron microscopy approaches. Results showed that the failure temperature of tested steel was deter- mined as 653 ℃, and the granular bainite was obtained when the cooling rate was higher than 10 ℃/s. In the rolled state, a certain amount of M/A islands was observed. During heating from RT to ET, M/A islands disappeared, and cementites and high dense compound precipitates （Nb, Mo, V）C with size of less than 10 nm precipitated in ferrite at ET （600 ℃）, which resulted in precipitation strengthening at ET.
文摘The nano-concentrates and flame retardant nano-coating were prepared in thhis study. The effect of nano-SiO2 on the corrosion resistance and fire resistance of ammonium polyphosphate-pentaerythritol-melamine （APP- PER-MEL） coating was investigated by differential thermal analysis （DTA）, scanning electron microscopy （SEM）, effective thermal conductivity （λ/d）, X-ray photoelectron spectroscopy （XPS） and fire protection test. The chemical action and endothermic effect of ammonium polyphosphate, pentaerythritol and melamine in traditional flame retardant coating were damaged by salt spray condition, whereas the flame-retardant additives in the nano-coating demonstrated the good chemical interaction in salt spray condition. The uniformly dispersed nano-SiO2 particles could improve corrosion resistance of the coating, and hence nano-coating could remain the good fire-resistant properties even after 500 h salt spray test.
