The mechanical properties of commercial dual phase （DP）, transformation induced plasticity （TRIP）, and high strength low alloy （HSLA-340） steel sheets are investigated and compared at various strain rates rangin...The mechanical properties of commercial dual phase （DP）, transformation induced plasticity （TRIP）, and high strength low alloy （HSLA-340） steel sheets are investigated and compared at various strain rates ranging from 0.001 7to 0.17 s-1 at ambient temperature.TRIP steel outperforms the other two materials , having comparable ductility and twice as large strength relative to DP steel.TRIP has larger strength and much larger ductility than HSLA-340.The exceuent ductility of TRIP800is due to its high strain hardening capability , which promotes stable plastic deformation.It is observed that the strain hardening rate in TRIP800does not decrease to zero at failure , as common in most materials in which failure is preceded by necking.展开更多
In order to simulate the hot-dipped galvanizing of dual-phase （DP） steel （wt%） 0.15C-0.1Si-1.7Mn, the DP steels were obtained by different annealing schedules. The effects of soaking temperature, time, and cooling...In order to simulate the hot-dipped galvanizing of dual-phase （DP） steel （wt%） 0.15C-0.1Si-1.7Mn, the DP steels were obtained by different annealing schedules. The effects of soaking temperature, time, and cooling rate on ferrite grain, volume fraction of martensite, and the fine structure of martensite were studied. Results showed that the yield strength （YS） of DP steel is sensitive to annealing schedule, while total elongation has no noticeable dependence on annealing schedule. Increasing soaking temperature from 790 to 850 ℃, the YS is the lowest at soaking temperature of 850 ℃. Changing CR1 from 6 to 24 ℃/s, the YS is the highest when CR1 is 12 ℃/s. Increasing soaking time from 30 to 100 s, the YS is the lowest at soaking time of 100 s. Besides, it was found that sufficient movable dislocations within ferrite grains and high martensite volume fraction can eliminate yield point elongation, decrease the YS, and increase ultimate tensile strength. Through TEM observations, it was also found that increasing annealing temperature promotes austenite transformation into twin martensite, and increases volume fraction of martensite at sufficient cooling rate. With increasing the martensite volume fraction, the deformation substructure in the ferrite is well developed.展开更多
文摘The mechanical properties of commercial dual phase （DP）, transformation induced plasticity （TRIP）, and high strength low alloy （HSLA-340） steel sheets are investigated and compared at various strain rates ranging from 0.001 7to 0.17 s-1 at ambient temperature.TRIP steel outperforms the other two materials , having comparable ductility and twice as large strength relative to DP steel.TRIP has larger strength and much larger ductility than HSLA-340.The exceuent ductility of TRIP800is due to its high strain hardening capability , which promotes stable plastic deformation.It is observed that the strain hardening rate in TRIP800does not decrease to zero at failure , as common in most materials in which failure is preceded by necking.
基金supported by the National Basic Research Program of China (No. 2011CB606306-2)Fundamental Research Funds for the Central Universities (No. N110607005)
文摘In order to simulate the hot-dipped galvanizing of dual-phase （DP） steel （wt%） 0.15C-0.1Si-1.7Mn, the DP steels were obtained by different annealing schedules. The effects of soaking temperature, time, and cooling rate on ferrite grain, volume fraction of martensite, and the fine structure of martensite were studied. Results showed that the yield strength （YS） of DP steel is sensitive to annealing schedule, while total elongation has no noticeable dependence on annealing schedule. Increasing soaking temperature from 790 to 850 ℃, the YS is the lowest at soaking temperature of 850 ℃. Changing CR1 from 6 to 24 ℃/s, the YS is the highest when CR1 is 12 ℃/s. Increasing soaking time from 30 to 100 s, the YS is the lowest at soaking time of 100 s. Besides, it was found that sufficient movable dislocations within ferrite grains and high martensite volume fraction can eliminate yield point elongation, decrease the YS, and increase ultimate tensile strength. Through TEM observations, it was also found that increasing annealing temperature promotes austenite transformation into twin martensite, and increases volume fraction of martensite at sufficient cooling rate. With increasing the martensite volume fraction, the deformation substructure in the ferrite is well developed.
