Effect of annealing temperature on microstructure and properties of warm rolled high manganese steel
The tensile properties and low-temperature toughness at-196 ℃ of medium carbon 25Mn steel after warm rolling and annealing treatment were measured,and the microstructure and impact fracture surface of the steel under different treatment conditions were observed.The recrystallization behavior of the experimental steel during annealing and its influence mechanism on mechanical properties were discussed.The results show that the experimental steel has basically completed recrystallization after annealing at 550 ℃for 1 h.By increasing the annealing temperature,the recrystallization structure gradually coarsens,leading to a decrease in the stability of austenite.Therefore,it is more prone to martensitic transformation during the deformation process,that is,the phase transformation induced plasticity(TRIP)mechanism gradually strengthens.Although this can alleviate the stress concentration generated during crack nucleation and propagation to a certain extent,the generation of martensite can also lead to a deterioration in the toughness and plasticity of the steel.At the same time,the results also indicate that even if the recrystallization is sufficient,there is still a certain amount of high-density dislocation cells and stacking faults in the fine austenite grains,resulting in a higher strength increment than fine grain strengthening.
high Mn steelwarm rollingrecrystallizationdeformation mechanism