Effect Of Heat Treatment On Mechanical And Magnetic Properties Of Magnetic Stainless Stee

The effect of heat treatment process on mechanical properties and microstructure and magnetic properties of the new magnetic stainless steel had been studied in this paper.The Thermo-Calc software had been used to calculate the steel equilibrium phase diagram.Using the optical microscopy,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)to observe the microstructure of steel,meanwhile testing the magnetic in different heat treatment of the steel,analyzes of the relevance of mechanical properties、microstructure and magnetic properties.Optimize the best heat treatment,and provides the test data and technical for the engineering research.The results showed that as the rise of solution temperature,the strength of the steel increasing,the strength and the toughness by water quench is better than air quench.The original microstructure of steel is ferritic、M23C6,and the number of the M23C6 decreases as the solution temperature increases.When the solution temperature is higher than 1000℃,the carbide quantity significantly reduced in the microstructure at room temperature and high-carbon martensite volume increased significantly,which is the main reason that with the rise of solution temperature,the strength increased.After 1070℃×1hWC treatment,the matrix structure is ferrite and martensite,the strength and toughness belong the best match.With the increase of tempering temperature,the strength of the steel is falling,and the impact energy value is rising,peaked at 700℃,and then with the temperature rise has a tendency to decline.In the same tempering temperature,the solution temperature is higher the strength is higher.After tempering,the microstructure is ferrite+martensite+M23C6 carbides,In the process of tempering,the high carbon martensite decomposition,it’s the main reason that as the tempering temperature rise,the strength decline and the impact increases,when the tempering temperature higher than 700℃,the carbide with mesh structure distribution on the original martensite and ferrite grain boundaries,thus the impact has a tendency to decline.Under the same magnetic field intensity,the solution temperature is higher,the lower the permeability,That is due to the quantity of high carbon martensite increases,the lattice structure aberrance rise,and produces a large number of defects such as dislocations lead to magnetic decline;And under the same magnetic field intensity,with tempering temperature rise,the permeability increase at first and then descend,the permeability best performance during 600℃～650℃,at this temperature,the high carbon martensite decompose fully,the lattice distortion smaller,and with temper temperature rise,the large granular carbides in the grain boundary is formed,the magnetic decline.Through this study,reach the best heat treatment process for the new type of magnetic stainless steel:solution temperature at 1070℃,holding 1h,water cooled,temper temperature at 600～650℃,holding 2h,water cooled.