Research On Non-magnet Magnetic Liner Strengthen And Its Mechanism

For the hardness of the magnetic liner protective layer material is low, and due to thelife of the magnetic liner is short. The subject is committed to improving the hardness ofhigh-manganese austenitic steel. This issue adjust the content of elements C, Cr, Ti, V traceelements while adding on the basis of the high manganese steel, solution heat treatment,diffusion aging treatment process parameters groping trial out of high strength and hardnessof the non-magnetic steel, as well as to study the mechanism and strengthening mechanismof trace elements. The results showed that:1) The equilibrium phases of the high manganese austenitic steel from200K~1600Kware calculated by using thermo-calc software, and using the result to draw up the progressof heat treatment. And test results show that the results are consistent with the experimentalresults, the Thermo-Calc software is a powerful tool for research on the high manganesesteel.2) The titanium element can refine the organization of high-manganese austenitic steel,thereby increasing the hardness of the material; The phases of super high manganesenon-magnetic steel after solution treatment are austenitic and TiC phase; after ageing at625℃~700℃, the M23C6phase precipitate from austenite, and the phase content increaseswith the temperature increasing until reach saturation at675℃, and the size of the phasehas been grown up at700℃. The titanium content varies between0to0.5%, the hardness ofhigh manganese austenitic steel after solution treatment and aging increase about15%. Thisshows that the role of titanium element in the aging process is not the main factor inincreasing the hardness, the aging treatment is mainly enhanced by precipitation of M23C6phase.3) Within the range of vanadium content from0.25%to0.97%, The phases of superhigh manganese non-magnetic steel after solution treatment are austenitic, and the phasesaging treatment are austenitic, M23C6phase and VC phase. With increasing vanadiumcontent, the inceasement of the high manganese austenitic steel’s hardness after solutiontreatment and aging is greater. V addition substantially enhance the high manganeseaustenitic steel’s hardness after ageing heat treatment, and the maximum hardness reach300HBW when the vanadium content is at0.97%. sizes of100nm~200nm M23C6particlesand sizes of10nm~70nm dispersed precipitated VC particles have been observed in austenitic steel. But the enhancement of hardness mainly depended on dispersed precipitatedVC particles. Finely dispersed precipitated VC particles have coherent orientationrelationship with austenitic. However, with growing up of the VC particles, the orientationrelationship don’t exit when the particles reach a certain degree size. And the content ofdislocation and stacking fault in high manganese austenitic steel increase with the vanadiumcontent increasing.