The effects of chemical composition and cooling rate after solidication on the grain coarsening temperature,T_(GC),of the V-Ti-N microalloyed steels have been investigated.It is shown that the T_(GC) may be obviously ...The effects of chemical composition and cooling rate after solidication on the grain coarsening temperature,T_(GC),of the V-Ti-N microalloyed steels have been investigated.It is shown that the T_(GC) may be obviously raised by adding even a little Ti to the base steel so as to pre- cipitate a great deal of fine Ti-bearing particles of about 10 nm.The T_(GC) does not increase with the cooling rate,as it is over a certain critical value.The T_(GC) is insensitive to any varia- tion of N content at simulated cooling condition of 150 mm continuous cast slab.The T_(GC) may be dropped down about 100℃ by adding 0.33 wt-%Mo to the steels.The sensitivi- ty of T_(GC) to cooling condition relates to the Ti and V contents.展开更多
The characteristics and the formation of the miscible particles in V-Ti-N microalloyed steels were studied.It was found that the vanadium to form V-Ti miscible particles starts to precipi- tate after pouring and cooli...The characteristics and the formation of the miscible particles in V-Ti-N microalloyed steels were studied.It was found that the vanadium to form V-Ti miscible particles starts to precipi- tate after pouring and cooling to temperature below 11 50℃ by means of the epitaxial precipi- tation on the pre-existing titanium nitrides.The vanadium content in the particles is markedly influenced by the cooling rate after solidification.展开更多
The strain hardening behaviors of 32Mn-TCr-1Mo-0.3N austenitic steel were characterized by a simple and effective method. The results show that Hollomon relationship is not applicable during total uniform deformation ...The strain hardening behaviors of 32Mn-TCr-1Mo-0.3N austenitic steel were characterized by a simple and effective method. The results show that Hollomon relationship is not applicable during total uniform deformation stage. The flow equation was proposed, Inσ=αexp（lnε/b）＋c. The variation rates of strain hardening exponents with true strain at 77 K are obviously higher than that at other temperatures and the value of d^2σ/dε^2 becomes positive during high strain stage. The characters of this variation are principal reasons for increasing elongation at 77 K. The forming of mechanical twin as well as ε-martensite leads to a high elongation at 77 K.展开更多
The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3Si13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3Si13.5B9 alloy annealed at 460℃ for 1 h consists of th...The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3Si13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3Si13.5B9 alloy annealed at 460℃ for 1 h consists of the DO3-type ordered region with spherical shape and disordered region. The size of DO3 ordered region increases with the annealing temperature. When the annealing temperature is 560℃, the size of the ordered region in the α-Fe(Si) grain is 14.0nm,which is nearly as large as that of the α-Fe(Si) grain (14.2 nm) and the degree of order of the α-Fe(Si) phase is about 0.78. When Fe73.5Cu1 Mo3Si13.5B9 amorphous alloy is annealed at 520℃， with the increment of the annealing time, the shape of the DO3 ordered region in the α-Fe(Si) phase is spheroidal at the beginning of the annealing and becomes spherical and has asize of 12.8 nm when the annealing time is 60 min. In addition, the DO3 superlattice lines of the α-Fe(Si) phase will vanish if Fe73.5Cu1Mo3Si13.5 B9 amorphous alloy is annealed for 1 h at 750℃.展开更多
An investigation was carried out of the morphology and microstructure of V-Ti complex carbonitride in steel 09MnVTiN during reheating under analytical electron microscope.The prior V-rich ellipsoid V-Ti complex carbon...An investigation was carried out of the morphology and microstructure of V-Ti complex carbonitride in steel 09MnVTiN during reheating under analytical electron microscope.The prior V-rich ellipsoid V-Ti complex carbonitride particles are replaced progressively by Ti-rich cubic ones as the reheating temperature elevated from 1050 to 1400℃.The Ti con- tents in the core and border of particles increase from 15 and 6% in hot-rolled specimens into 84 and94% at 1400℃ respectively.展开更多
Determination of soil Se by anodic stripping voltammetry (ASV) with aurum thin-film electrode (ATFE) over-comes the interference of gold peak with selenium peak, and thus has a higher sensitivity with the mininiumdete...Determination of soil Se by anodic stripping voltammetry (ASV) with aurum thin-film electrode (ATFE) over-comes the interference of gold peak with selenium peak, and thus has a higher sensitivity with the mininiumdetectable concentration being 0.017 μg/mL, the standard deviation of the measured results less than 0.012 μg/g,the coefficient of variation lower than 10%, and the recovery rate between 86% to 103%. Besides the measurementconditions, the digestion of soil sample was also studied in detail.展开更多
The heterogeneous distribution of C and metallic alloying elements as well as the phase com- position changes before and after cold deformation of an Fe-Mn-Cr-C alloy have been stu- died by the use of Mssbauer spectro...The heterogeneous distribution of C and metallic alloying elements as well as the phase com- position changes before and after cold deformation of an Fe-Mn-Cr-C alloy have been stu- died by the use of Mssbauer spectroscopy.The austenites without and with C and metallic alloying elements are found in the alloy in as-solid solution state.While the martensites with- out and with C and alloying elements may be induced by cold deformation.The transforma- tion from austenite to martensite in the alloy is confirmed via theoretical computation and ex- periments to be controlled by the number of covalent electron pairs forming covalent bond in austenitic crystal cell of the alloy.The formation of strong covalent bond between C and me- tallic elements can vigorously retard the γ/α' transformation.展开更多
文摘The effects of chemical composition and cooling rate after solidication on the grain coarsening temperature,T_(GC),of the V-Ti-N microalloyed steels have been investigated.It is shown that the T_(GC) may be obviously raised by adding even a little Ti to the base steel so as to pre- cipitate a great deal of fine Ti-bearing particles of about 10 nm.The T_(GC) does not increase with the cooling rate,as it is over a certain critical value.The T_(GC) is insensitive to any varia- tion of N content at simulated cooling condition of 150 mm continuous cast slab.The T_(GC) may be dropped down about 100℃ by adding 0.33 wt-%Mo to the steels.The sensitivi- ty of T_(GC) to cooling condition relates to the Ti and V contents.
文摘The characteristics and the formation of the miscible particles in V-Ti-N microalloyed steels were studied.It was found that the vanadium to form V-Ti miscible particles starts to precipi- tate after pouring and cooling to temperature below 11 50℃ by means of the epitaxial precipi- tation on the pre-existing titanium nitrides.The vanadium content in the particles is markedly influenced by the cooling rate after solidification.
基金This work was supported by the National Natural Science Foundation of China No. 59771001Natural Science Foundation of Hebei Province under grant No. E200400197.
文摘The strain hardening behaviors of 32Mn-TCr-1Mo-0.3N austenitic steel were characterized by a simple and effective method. The results show that Hollomon relationship is not applicable during total uniform deformation stage. The flow equation was proposed, Inσ=αexp（lnε/b）＋c. The variation rates of strain hardening exponents with true strain at 77 K are obviously higher than that at other temperatures and the value of d^2σ/dε^2 becomes positive during high strain stage. The characters of this variation are principal reasons for increasing elongation at 77 K. The forming of mechanical twin as well as ε-martensite leads to a high elongation at 77 K.
文摘The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3Si13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3Si13.5B9 alloy annealed at 460℃ for 1 h consists of the DO3-type ordered region with spherical shape and disordered region. The size of DO3 ordered region increases with the annealing temperature. When the annealing temperature is 560℃, the size of the ordered region in the α-Fe(Si) grain is 14.0nm,which is nearly as large as that of the α-Fe(Si) grain (14.2 nm) and the degree of order of the α-Fe(Si) phase is about 0.78. When Fe73.5Cu1 Mo3Si13.5B9 amorphous alloy is annealed at 520℃， with the increment of the annealing time, the shape of the DO3 ordered region in the α-Fe(Si) phase is spheroidal at the beginning of the annealing and becomes spherical and has asize of 12.8 nm when the annealing time is 60 min. In addition, the DO3 superlattice lines of the α-Fe(Si) phase will vanish if Fe73.5Cu1Mo3Si13.5 B9 amorphous alloy is annealed for 1 h at 750℃.
文摘An investigation was carried out of the morphology and microstructure of V-Ti complex carbonitride in steel 09MnVTiN during reheating under analytical electron microscope.The prior V-rich ellipsoid V-Ti complex carbonitride particles are replaced progressively by Ti-rich cubic ones as the reheating temperature elevated from 1050 to 1400℃.The Ti con- tents in the core and border of particles increase from 15 and 6% in hot-rolled specimens into 84 and94% at 1400℃ respectively.
文摘Determination of soil Se by anodic stripping voltammetry (ASV) with aurum thin-film electrode (ATFE) over-comes the interference of gold peak with selenium peak, and thus has a higher sensitivity with the mininiumdetectable concentration being 0.017 μg/mL, the standard deviation of the measured results less than 0.012 μg/g,the coefficient of variation lower than 10%, and the recovery rate between 86% to 103%. Besides the measurementconditions, the digestion of soil sample was also studied in detail.
文摘The heterogeneous distribution of C and metallic alloying elements as well as the phase com- position changes before and after cold deformation of an Fe-Mn-Cr-C alloy have been stu- died by the use of Mssbauer spectroscopy.The austenites without and with C and metallic alloying elements are found in the alloy in as-solid solution state.While the martensites with- out and with C and alloying elements may be induced by cold deformation.The transforma- tion from austenite to martensite in the alloy is confirmed via theoretical computation and ex- periments to be controlled by the number of covalent electron pairs forming covalent bond in austenitic crystal cell of the alloy.The formation of strong covalent bond between C and me- tallic elements can vigorously retard the γ/α' transformation.
