The plasticity map of 304HC stainless steel was determined by using tensile and compressive test. The effect of Cu on the hot plasticity of 304HC stainless steel was analyzed. The microstructure, inclusion and fractur...The plasticity map of 304HC stainless steel was determined by using tensile and compressive test. The effect of Cu on the hot plasticity of 304HC stainless steel was analyzed. The microstructure, inclusion and fracture surface were studied by using the method of optical microscopy, SEM, EDS and EPMA. The results showed that Cu has effect on the hot plasticity and the hot plasticity of 304HC stainless steel decrease with the increase of Cu content. The deformation temperature also has much effect on the hot plasticity, the suitable deformation temperature are 1100-1200℃. The reason is that the brittle compounds were precipitated from austenite during cooling. These brittle compounds are Cu2S, Cu2O and PbCI etc.展开更多
Hot plasticity of a nitrogen alloyed 25Cr 7Ni-4Mo duplex stainless steel was investigated. The results indicate that the main factors affecting the hot plasticity of duplex stainless steel are listed as follows： coal...Hot plasticity of a nitrogen alloyed 25Cr 7Ni-4Mo duplex stainless steel was investigated. The results indicate that the main factors affecting the hot plasticity of duplex stainless steel are listed as follows： coalescent force of phase interface, microstructure, and the phase ratio and difference between the mechanical properties of ferrite and austenite. The heat treatment and sulphur contents have a notable effect on the hot plasticity. The reasonable heat treatments and the increased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.展开更多
The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERM...The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTOR-Z simulator,at temperature between 1030 and 1300 ℃,with strain rate from 1 to 50 s-1 and strain ε=0.8.The variations of flow stress with deformation temperature and strain rate were presented.Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM,SEM and TEM.Moreover,hot plasticity characteristics of alloy were analyzed by temperature-reduction of area curves.The results showed that available hot working temperature for G3,G3-Z and 825 was 1100 to 1240 ℃,1130 to 1220 ℃ and 1050 to 1240 ℃,respectively.The reliable information on hot working in the alloy pilot production in steelwork is given.展开更多
Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its...Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its applications on the prediction of sheet forming process. Then, a new macroscopic constitutive model is introduced, which possesses an enhanced description capacity of tension/compression anisotropy and anisotropic hardening. In order to take into account the twinning process of hexagonal close-packed material, a modified hierarchical multi-scale model is also established with adequate accuracy in a shorter computational time. The advanced forming limit of sheet metal, mainly about aluminum alloy, is also investigated. Besides the above theory developments, some new sheet metal forming technologies are reviewed simultaneously. The warm forming technology of Mg alloy is discussed. New processes to form sheet parts and to bend tubes are proposed by using hard granules. On the other hand, a new kind of ultra-high-strength steel based on typical22 Mn B5 by introducing more residual austenite and Cu-rich phase to increase the elongation and strength and its novel forming method that integrates hot stamping and quenching participation are proposed. Progresses in sheet hydroforming,press forging and electromagnetic forming of sheet metal parts are also summarized.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.59995440)Liaoning Provincial Natural Science Foundation of China(No.2001101021).
文摘The plasticity map of 304HC stainless steel was determined by using tensile and compressive test. The effect of Cu on the hot plasticity of 304HC stainless steel was analyzed. The microstructure, inclusion and fracture surface were studied by using the method of optical microscopy, SEM, EDS and EPMA. The results showed that Cu has effect on the hot plasticity and the hot plasticity of 304HC stainless steel decrease with the increase of Cu content. The deformation temperature also has much effect on the hot plasticity, the suitable deformation temperature are 1100-1200℃. The reason is that the brittle compounds were precipitated from austenite during cooling. These brittle compounds are Cu2S, Cu2O and PbCI etc.
文摘Hot plasticity of a nitrogen alloyed 25Cr 7Ni-4Mo duplex stainless steel was investigated. The results indicate that the main factors affecting the hot plasticity of duplex stainless steel are listed as follows： coalescent force of phase interface, microstructure, and the phase ratio and difference between the mechanical properties of ferrite and austenite. The heat treatment and sulphur contents have a notable effect on the hot plasticity. The reasonable heat treatments and the increased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.
文摘The G3 and 825 alloys,with excellent combination of mechanical properties and corrosion resistance,can be used in hot,and acid environments.Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTOR-Z simulator,at temperature between 1030 and 1300 ℃,with strain rate from 1 to 50 s-1 and strain ε=0.8.The variations of flow stress with deformation temperature and strain rate were presented.Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM,SEM and TEM.Moreover,hot plasticity characteristics of alloy were analyzed by temperature-reduction of area curves.The results showed that available hot working temperature for G3,G3-Z and 825 was 1100 to 1240 ℃,1130 to 1220 ℃ and 1050 to 1240 ℃,respectively.The reliable information on hot working in the alloy pilot production in steelwork is given.
文摘Developments of new sheet metal forming technology and theory in China are reviewed in detail in this paper.Advances of crystal plasticity on the deformation mechanism of Mg alloy are firstly described, especially its applications on the prediction of sheet forming process. Then, a new macroscopic constitutive model is introduced, which possesses an enhanced description capacity of tension/compression anisotropy and anisotropic hardening. In order to take into account the twinning process of hexagonal close-packed material, a modified hierarchical multi-scale model is also established with adequate accuracy in a shorter computational time. The advanced forming limit of sheet metal, mainly about aluminum alloy, is also investigated. Besides the above theory developments, some new sheet metal forming technologies are reviewed simultaneously. The warm forming technology of Mg alloy is discussed. New processes to form sheet parts and to bend tubes are proposed by using hard granules. On the other hand, a new kind of ultra-high-strength steel based on typical22 Mn B5 by introducing more residual austenite and Cu-rich phase to increase the elongation and strength and its novel forming method that integrates hot stamping and quenching participation are proposed. Progresses in sheet hydroforming,press forging and electromagnetic forming of sheet metal parts are also summarized.
