For wear-resistant plates, temperature changes during production and processing will directly affect the performance of the entire plate. Therefore, the effect of isothermal treatment of wear-resistant steel plates has been studied for a long time. It was found that the continuous cooling transition curve of wear-resistant plates at different heating temperatures The microstructure, phases and similar structural phases have also changed accordingly.
The research methods of isothermal treatment of wear-resistant plates include many excellent technologies, such as optical microscope, transmission electron microscope, X-ray diffractometer and electron backscatter diffraction technology. As the annealing temperature increases, the proportion of ferrite in the wear-resistant plate will gradually decrease, and the increase is bainite, and the residual austenite will be distributed in the ferrite crystal in elliptical and thin strips. Boundary and intragranular.
When the heating temperature is reduced from the complete austenitization temperature to a higher temperature in the two-phase region, the ferrite transformation zone in the continuous cooling transformation curve of the wear plate shifts to the left. At this time, as long as heating and holding at 790°C, a multi-phase structure containing ferrite, bainite and retained austenite can be obtained.
When the holding temperature is further increased, the process time will directly affect the ferrite grain size, the amount of ferrite, and the dislocation density and precipitation amount on the ferrite matrix in the wear plate; with the holding time of the bainite zone With the extension of, the volume fraction of retained austenite in the wear-resistant steel plate first increases and then decreases, and the carbon content in the retained austenite increases.
When the heating temperature is within the two-phase range, as the heating temperature decreases, the ferrite transformation is delayed, and the carbon content of austenite is also different. In the same tensile deformation stage, the increasing rate of the austenite conversion rate is different, which makes the continuous cooling transformation curve of the wear-resistant plate shift to the right.
In addition, if the isothermal time is the same, the higher the isothermal temperature, the greater the carbon content in the retained austenite, and the ferrite, bainite grain boundary or phase interface in the wear-resistant steel plate will generate phases of large-grain austenite above 1μm. Change, corresponding to its performance will also change.
