To simulate the DIWA353 steel used in boiler nearby recrystallization temperature accurately by using finite element,the high temperature constitutive model of this material must be researched firstly.Thermal simulati...To simulate the DIWA353 steel used in boiler nearby recrystallization temperature accurately by using finite element,the high temperature constitutive model of this material must be researched firstly.Thermal simulation experimental machine is used to do the high temperature hot compression experiments for the DIWA353 steel used in boiler under different strain rates and temperatures nearby recrystallization temperature.Multi-bank data of true stress-true strain is gotten,and the hot deformation activation energy of DIWA353 is obtained,and the constitutive equation of steady-state flow stress under the circumstance of high temperature is constructed.The results show that DIWA353 steel is positive strain rate sensitized material when it is at temperature of 850-1050 ℃,and the steady-state flow stress decreases with the increase of deformation temperature,but increases with the increase of strain rate.展开更多
The Nb-Ti microalloyed high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical properties and textures.The experimental results show that experimental steel...The Nb-Ti microalloyed high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical properties and textures.The experimental results show that experimental steel is incomplete recrystallization at 750℃ annealing,but complete recrystallization from 780℃ to 870℃ under experimental conditions.When the annealing temperature was increased,the yield strength and tensile strength would gradually reduce,the plastic strain ratio and yield point elongation would gradually increase.The yield strength,tensile strength,elongation,the plastic strain ratio and the strain hardening exponent were approximate 300MPa,410MPa,36.5%,1.7 and 0.22 respectively under annealing temperature 810℃ to 840℃.When the annealing temperature was increased,the α-textures and γ-textures were gradually weakened,and the α-textures have a trend to {111} texture.Therefore,the suggestion of the optimal recrystallization annealing temperature is about 810℃ to 840℃ in industrial production.展开更多
According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing...According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing,in which the thickness of tungsten slice is 0.17 mm.In order to get the best mechanical properties,the brazing temperature is suggested to be controlled under the recrystallization temperature of tungsten,while the recrystallization temperature is affected directly by the thickness of tungsten.Because of little research and application on the brazing of thin tungsten slice of 0.17 mm and copper,tensile tests are done to get the mechanical properties of tungsten slices which experience different brazing temperatures.In keeping the inner relationships between the mechanical properties and temperature,another experiment is done by using SEM to scan the microstructures including the size and distribution of crystals.Finally we determine the recrystallization temperature of tungsten slice of 0.17 mm,and get the best parameters of W/Cu brazing for scrapers of primary collimator in CSNS/RCS.展开更多
基金Sponsored by the Heilongjiang Province Science and Technology Department(Grant No.GC06A515)
文摘To simulate the DIWA353 steel used in boiler nearby recrystallization temperature accurately by using finite element,the high temperature constitutive model of this material must be researched firstly.Thermal simulation experimental machine is used to do the high temperature hot compression experiments for the DIWA353 steel used in boiler under different strain rates and temperatures nearby recrystallization temperature.Multi-bank data of true stress-true strain is gotten,and the hot deformation activation energy of DIWA353 is obtained,and the constitutive equation of steady-state flow stress under the circumstance of high temperature is constructed.The results show that DIWA353 steel is positive strain rate sensitized material when it is at temperature of 850-1050 ℃,and the steady-state flow stress decreases with the increase of deformation temperature,but increases with the increase of strain rate.
文摘The Nb-Ti microalloyed high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical properties and textures.The experimental results show that experimental steel is incomplete recrystallization at 750℃ annealing,but complete recrystallization from 780℃ to 870℃ under experimental conditions.When the annealing temperature was increased,the yield strength and tensile strength would gradually reduce,the plastic strain ratio and yield point elongation would gradually increase.The yield strength,tensile strength,elongation,the plastic strain ratio and the strain hardening exponent were approximate 300MPa,410MPa,36.5%,1.7 and 0.22 respectively under annealing temperature 810℃ to 840℃.When the annealing temperature was increased,the α-textures and γ-textures were gradually weakened,and the α-textures have a trend to {111} texture.Therefore,the suggestion of the optimal recrystallization annealing temperature is about 810℃ to 840℃ in industrial production.
基金supported by China Spallation Neutron Source(CSNS)
文摘According to the requirements for the beam collimation system of the rapid cycling synchrotron(RCS)of China Spallation Neutron Source(CSNS),the main structure of a scraper of primary collimator is made by W/Cu brazing,in which the thickness of tungsten slice is 0.17 mm.In order to get the best mechanical properties,the brazing temperature is suggested to be controlled under the recrystallization temperature of tungsten,while the recrystallization temperature is affected directly by the thickness of tungsten.Because of little research and application on the brazing of thin tungsten slice of 0.17 mm and copper,tensile tests are done to get the mechanical properties of tungsten slices which experience different brazing temperatures.In keeping the inner relationships between the mechanical properties and temperature,another experiment is done by using SEM to scan the microstructures including the size and distribution of crystals.Finally we determine the recrystallization temperature of tungsten slice of 0.17 mm,and get the best parameters of W/Cu brazing for scrapers of primary collimator in CSNS/RCS.
