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Molybdenum has a very important role in the production of high manganese steel casting, xinyuanzhu through continuous casting experiments.
1. Molybdenum can effectively inhibit carburization aggregation between 450-600 ℃, resulting in the carbide of molybdenum diffusely distributed in austenite with very small size, through the diffusion strengthening effect, strengthening the austenite organization, so that the strength and hardness of high manganese steel increased, deformation hardening properties enhanced, thus improving the anti-wear ability.

2. Molybdenum can effectively inhibit the precipitation of grain boundary carbides in the cooling process of high manganese steel. High manganese steel with chromium makes the grain boundary carbide precipitation tendency greatly improved, high manganese steel in molybdenum, chromium two elements of the compound to join, can make the beneficial effect of two alloying elements at the same time.

3. molybdenum and nickel in the inhibition of austenite precipitation of needle carbide has a similar role, high manganese steel with molybdenum, needle carbide becomes shorter, the number of significantly reduced, the precipitation temperature increases, can make the casting embrittlement temperature to about 350 ℃. Therefore, molybdenum-containing high manganese steel is mainly used for thick-walled castings, but also for working in the higher temperature (<350 ℃) parts.

3.1 molybdenum in austenitic manganese steel condensation, the Department of solid solution in the austenite, partly distributed in the carbide. Molybdenum can improve the tendency of austenite development along the dendrite, and can improve the stability of austenite. Molybdenum can inhibit carbide precipitation and promote the formation of pearlite. Therefore, the addition of molybdenum has a good effect on improving the crack resistance and water quenching quality of large-section castings, as well as on preventing embrittlement when welding, cutting or at temperatures above 275 degrees Celsius. Molybdenum significantly increases the yield strength of the steel without reducing the toughness, and even increases it. The content of molybdenum in steel is generally less than 2%.

3.2 molybdenum on the mechanical properties of high manganese steel in the as-cast state due to the reduction of grain boundary carbides and thus show a reduction in brittleness. After heat treatment, the steel contains less than 2% molybdenum yield strength increase, while the plasticity of the tensile strength is not reduced. High manganese steels can be alloyed with molybdenum by using a water-toughened treatment to solidify the molybdenum in the austenite. Can also use precipitation strengthening treatment, so that the austenite precipitation of diffuse distribution of carbide, so that steel strengthening hair to improve wear resistance.

3.3 In the process of cooling phase transformation of high manganese steel, molybdenum inhibits the decomposition of austenite. Molybdenum can also and iron and carbon to form a complex carburized body. As molybdenum and carbon bonding ability is strong, when the molybdenum content is high can form special carbides such as molybdenum carbide, molybdenum carbide, etc..

3.4 molybdenum in the steel diffusion rate is much smaller than carbon, so that the carbide in the steel dissolution rate slows down, in the molybdenum content of more than 0.5% of this rate is very slow. Therefore, molybdenum-containing high manganese steel in the crystallization of solidification after carbide precipitation is small, has appeared in the carbide in the heat treatment and difficult to dissolve into the austenite matrix. This effect can steel in the needle carbide precipitation time delayed, and make its precipitation temperature to low temperature direction. When the molybdenum content reaches a certain amount, it can basically eliminate the carbide in the as-cast organization. Because chromium can make the cast organization in a large number of carbide precipitation, and the opposite effect of molybdenum, so often in the high manganese steel containing chromium at the same time to add molybdenum, in order to reduce the brittleness of the cast organization. The precipitated carbide is difficult to dissolve during the heating process. This role can be used for precipitation strengthening treatment, so that the steel appears in the diffuse distribution of grain carbide, improve the steel resistance to abrasive wear.

3.5 Molybdenum can also change the morphology of carbides. Molybdenum-bearing steels rarely have germanium carbides but tend to become unmaterialized or granular. As the cast carbide decreases, the distribution of its shape also changes, so increasing the carbon content of the steel does not cause excessive carbide appearance. According to the results of the study , the carbon content can be increased to about 1.7%. The increased carbon content is conducive to improving the wear resistance of the material under non-strength abrasive wear conditions.

3.6 molybdenum can also refine the microstructure of the steel after water toughness treatment, in the same chemical composition, heat treatment methods and processes, high manganese steel containing molybdenum in the heat treatment of the grain is relatively fine.
In short, molybdenum is a useful element for high manganese, practice has proved that the high manganese steel containing molybdenum has good wear resistance in the worse abrasive wear conditions.

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