Study On The Microstructure And Properties Of Cold Rolled Austenitic Steelafter High Pressure Annealing Treatments

In this paper,TWIP steel and 301 austenitic stainless steel are cold rolled,and annealing treated as high-pressure.Optical microscope,X-Ray diffraction,scanning electron microscopy,electron backscatter diffraction analyzer,micro-hardness and universal tensile tester are used to study the changes in the microstructure and properties of the two kind of austenitic steels.The results of the research show that,after high pressure annealing treatment as pressure of 5GPa and time of 1h,the hardness of the cold-rolled TWIP steel is overall a downward trend with the increasing of annealing temperature;When the annealing temperature and time are constant,yield strength,tensile strength and yield ratio of the TWIP steel increases with the pressure increasing,but elongation decreases with the pressure increasing;When the annealing pressure and time are constant,tensile strength of the TWIP steel firstly increases and then decreases with the temperature increasing,yield strength and yield ratio decreases with the temperature increasing,but elongation increases with the temperature increasing.By controlling the parameter of high pressure annealing treatment(0.5 GPa~5 GPa,500 ?~900 ?,30min~120 min),we can obtain from 296 MPa to 1584 MPa of yield strength,from 741 MPa to 1794 MPa of tensile strength,from 0.4% to 48.0% of elongation;The high-pressure leads austenite to martensite,and obtaining the finer grain organization.after high pressure annealing treatment as pressure of 5 GPa and time of 1 h,the hardness of cold-rolled 301 austenitic stainless steel is overall a downward trend with the increasing of annealing temperature;When the annealing temperature and time are constant,yield strength,tensile strength and yield ratio of the TWIP steel increases with the pressure increasing,but elongation decreases with the pressure increasing;When the annealing pressure and time are constant,yield strength,tensile strength and yield ratio of the TWIP steel decreases with the temperature increasing,but elongation increases with the temperature increasing;When the annealing pressure and temperature are constant,with the time increasing,yield strength,tensile strength and yield ratio of the 301 austenitic stainless steel firstly increases and then decreases,but elongation firstly decrease and then increase;By controlling the parameter of high pressure annealing treatment(1 GPa~5 GPa,400 ?~900 ?,3 min~60 min),we can obtain from 354 MPa to 1337 MPa of yield strength,from 713 MPa to 1827 MPa of tensile strength,from 12.3% to 56.0% of elongation;Pressure,as the main high-pressure annealing treatment parameter,can control the microstructure and performances of the two austenitic steels.