Research On Vanadium Alloying Of Low Density And High Strength Steel

It is necessary to study the effect of vanadium alloying on the microstructure and properties,which provides theoretical basis for the subsequent alloying due to the blank of research on Fe-Mn-Al-C low density steel vanadium alloying in the public report.This paper designs three kinds(0.0%,0.5%,1.0%)steel vanadium content,through the mechanical properties test and microstructure observation.The compression experiments of three kinds of Fe-Mn-Al-C low density steels with content of 0,0.5wt%and lwt%were conducted by Gleeble-3800 hot simulator at different deformation temperatures from 950? to 1150? and different strain rates from 0.01s-1 to 10s-1.The hot deformation behaviors of this low density steels were studied at high temperatures and the microstructures before and after compression were observed.1.Finding that the second phase of Fe-Mn-Al-C carbon steel which represented by Fe-26Mn-9Al-1C is Kappa—carbide.It is difficult to dissolve in low solution temperature,and when a large number of dissolution high temperature,austenite grain coarsening,and austenite grain coarsening,kappa-large size carbide as the main second phase to further improve the performance of low density steel.The large size Kappa-carbide as the main second phase is difficult to further improve the performance of low density steel.2.With the increase of solution temperature,the grain refining effect is obvious.At 1000? solution temperature,the grain size is still above the level of 9.Due to the fine grain strengthening,the strength is increased,and the work hardening rate is larger.The addition of vanadium is 0.5%make the better strength and toughness match because of producing VC phase and the precipitation of the way at the edge to produce precipitation,precipitation strengthening mechanism,nail wall dislocations and grain,the Fe-26Mn-9Al-1C intensity increases,and refine the austenite grain to fine grain strengthening when solution temperature is 880 ?.But adding too much vanadium brings more damage to the plastic toughness.3.Fe-26Mn-9Al-1C low density of vanadium in the steel with vanadium carbide phase,delayed the aging peak,and a substantial increase in peak intensity,compared with adding 1%vanadium,achieve the best strength and toughness,joined in 0.5%,and the optimum heat treatment system:880? × 1h + 590? × 5h.carbon vanadium that consumes a content of carbon atoms,aging,carbide spinodal decomposition driven reduction,precipitation strengthening weakened,resulting in a solid solution after aging at low strength increment.4.The results show that if vanadium content increases,the peak flow stress increases when not fully dynamic recrystallization;if the vanadium content becomes bigger,the austenite recrystallization grain size is smaller when fully recrystallization,which leads to high vanadium steel in work hardening and recrystallization softening in stable stage of smooth curve much higher,which means that the flow stress is larger;three steels' thermal deformation activation energy:Q1#=389.372 KJ/mol,Q2#=439.375 KJ/mol,Q3#=548.002 KJ/mol,which shows that the thermal activation can be greatly increased with the increase of vanadium content.