Trials to develop a C-Mn-Mo-Nb type fire-resistant steel have been carried out by adopting recrystallization rolling (RCR) + air cooling (AC),two-stage rolling (TSR) + AC and RCR + water cooling (WC).Both RCR and TSR ...Trials to develop a C-Mn-Mo-Nb type fire-resistant steel have been carried out by adopting recrystallization rolling (RCR) + air cooling (AC),two-stage rolling (TSR) + AC and RCR + water cooling (WC).Both RCR and TSR followed by AC resulted in polygonal ferrite (F) + pearlite (P) microstructure,while F + bainite (B) microstructure was formed by RCR + WC.The plates with F+P microstructure show tensile strengths ≥490MPa,while those with F+B exhibit tensile strengths ≥590MPa.All the plates show favorable low yield ratios ≤ 0.75,good charpy v-notch impact property 】101J at 0℃ and satisfactory high temperature strength (≥2/3 of room temperature yield strength retained at 600℃).展开更多
In order to ensure fire-resistant property of the steel under the condition of the least molybdenum content,effects of molybdenum on microstructure and properties of the fire-resistant construction steel,specially on ...In order to ensure fire-resistant property of the steel under the condition of the least molybdenum content,effects of molybdenum on microstructure and properties of the fire-resistant construction steel,specially on high temperature strength were investigated.The results show that the room temperature and high temperature strength of the steel is enhanced due to increased Mo content but the impact toughness deteriorates at the same time.The fraction of bainite in the microstructure increases with increasing Mo content while the fractions of polygonal ferrite and pearlite decrease.Comparing with the steel of adding Nb alone,it was obvious that combined addition of Mo and Nb could provide better effect in high temperature strengthening.Addition of 0.25mass% Mo in the steel containing Nb could meet fire-resistant requirements of the construction steel and provide better economical effectiveness.展开更多
文摘Trials to develop a C-Mn-Mo-Nb type fire-resistant steel have been carried out by adopting recrystallization rolling (RCR) + air cooling (AC),two-stage rolling (TSR) + AC and RCR + water cooling (WC).Both RCR and TSR followed by AC resulted in polygonal ferrite (F) + pearlite (P) microstructure,while F + bainite (B) microstructure was formed by RCR + WC.The plates with F+P microstructure show tensile strengths ≥490MPa,while those with F+B exhibit tensile strengths ≥590MPa.All the plates show favorable low yield ratios ≤ 0.75,good charpy v-notch impact property 】101J at 0℃ and satisfactory high temperature strength (≥2/3 of room temperature yield strength retained at 600℃).
文摘In order to ensure fire-resistant property of the steel under the condition of the least molybdenum content,effects of molybdenum on microstructure and properties of the fire-resistant construction steel,specially on high temperature strength were investigated.The results show that the room temperature and high temperature strength of the steel is enhanced due to increased Mo content but the impact toughness deteriorates at the same time.The fraction of bainite in the microstructure increases with increasing Mo content while the fractions of polygonal ferrite and pearlite decrease.Comparing with the steel of adding Nb alone,it was obvious that combined addition of Mo and Nb could provide better effect in high temperature strengthening.Addition of 0.25mass% Mo in the steel containing Nb could meet fire-resistant requirements of the construction steel and provide better economical effectiveness.
