A few questions need to be noticed in alloy steel heat treatment

A few questions need to be noticed in alloy steel heat treatment
In recent years the literature has reported on improving austenitic manganese steel high performance aspects of the progress. The alloying of high manganese steel is mainly through the traditional ingredients of high manganese steel with Cr, Mo, V, Ti and rare earth elements such as to improve its performance by, including the use of Cr is particularly widespread. Different tempering temperature to satisfy the organization of high manganese steel and common high manganese steel, the structure, the change of resistance and the wear-resisting performance is studied, the results found that: in high manganese steel under the condition of carbon content is relatively low, the wear-resisting performance is better than that of common high manganese steel. And high manganese steel at different tempering temperature of different organizational structure shows different wear resistance.
In high manganese steel after water toughening treatment, with the tempering temperature increased to 250 ℃, the high manganese steel wear quantity reduced, wear resistance increase, for maximum value at 250 ℃. When temperature rose from 250 ℃ to 250 ℃, its wear is a slight increase in wear resistance decreased, but still better than high manganese steel and the wear resistance of conventional water toughening treatment. When the temperature continued to rise to 500 ℃, the wear volume continue to increase, wear-resisting performance, lower than when the water toughening state of wear resistance, which further proves the existence of high manganese steel orderly micro zone.
For common high manganese steel, as the temperature increases, the austenitic matrix also happened to the carbon atoms in the migration, and the form C - Mn atoms in Mn, but due to the combination between the manganese, carbon atoms are relatively weak, the short range orderly micro area relatively little size, lattice distortion after 250 ℃ tempering a certain degree of recovery, so after 250 ℃ tempering of abrasion resistance than water toughening state almost no improve abrasion resistance. Due to solid solution strengthening effect is abate, the wear-resisting performance has declined slightly. When tempering temperature continue rose from 250 ℃ to 250 ℃, the activity of carbon atoms of high manganese steel and continue to increases with the rise of temperature, this temperature after tempering treatment is still no carbide precipitation, but at the moment, further reduce the austenitic lattice distortion degree, solid solution strengthening effect is abate, but because the carbide precipitation, there are still a lot of micro zone exists, the wear-resisting performance relative to the 250 ℃ tempering have fallen, but still higher than water toughening state of wear resistance. For common high manganese steel, when the temperature to 400 ℃, certain carbon-rich micro zone can be seen from the diffraction spectrum line carbide precipitation, at this point, the new precipitation of carbides have not grown up, dispersion strengthening effect is ideal. Another slightly in front of the area is still in the carbide precipitation structure state, because the state of the structure of micro area for carbon-rich area, so orderly C - Mn atom of relatively rich. These dispersion evenly distributed micro zone and dispersive distribution of carbide para wrong pinning effect to a certain extent, compensate for the effect of solid solution strengthening abate, so the macro mechanical properties of wear-resisting performance is not obvious. When the temperature continued to rise to 500 ℃, the high manganese steel began to precipitation carbides, the basic austenitic lattice constant has tended to be normal, but due to the precipitation of carbide alloy, the matrix carbon content decreases significantly, greatly influenced the formation of ordered micro area, thus the effect of work hardening, so macro wear-resisting performance is on the decline.
From the above analysis, it is not hard to see the C - orderly Mn atom of micro area clusters has an important influence on the wear resistance of high manganese steel. Water toughening treatment of high manganese steel, and again after 250 ℃ tempering treatment, due to the Cr to the C - Mn atom to the "hinge", it shows the common high manganese steel wear resistance is higher than the carbon content is higher. Of high manganese steel after tempering temperature to 500 ℃, due to the influence of carbide precipitation, orderly clusters reinforcement is abate, coupled with solid solution strengthening effect abate, the wear-resisting performance is significantly lower.