Manganese Steel (high manganese steel)
The commonly used high manganese steel in China brand and its scope of application are: ZGMn13-1 (C 1.10%~1.50%) for low impact parts, ZGMn13-2 (C1.00%~1.40%) for ordinary parts, ZGMn13-3 (C0.90%~1.30%) for complex parts, ZGMn13-4 (C0.90%~1.20%) for high impact parts. The manganese content of the above four kinds of grade steels is 11.0%~14.0%.
During the cold deformation of impact load, the steel is strengthened by the large increase of dislocation density, dislocation delivery, dislocation plug deposition, and the interaction of dislocation and solute atoms. This is an important reason for processing hardening. Another important reason is that the layer error energy of high manganese autenite is low, and it is prone to stacking layer error during deformation, thus creating conditions for the formation of ε martensite and the production of deformation twin. High density dislocation, dislocation deposition and entanglement can often be seen in the deformation hardening layer of conventional high manganese steel.ε The appearance of martensite and deformed twin makes the steel difficult to deform, especially because the latter is more important. The above factors make the hardening layer of high manganese steel strengthened to a high degree, and the hardness is greatly improved.
High manganese steel is easy to harden, so it is difficult to process, the vast majority of castings, a very small amount of forging method processing. The casting performance of high-manganese steel is better. The melting point of steel is low (about 14 ()()℃), the temperature interval of liquid and solid line of steel is small (about 50℃), the thermal conductivity of steel is low, so the molten liquidity is good, easy to pour molding. The wire expansion coefficient of high manganese steel is 1.5 times that of pure iron and 2 times that of carbon steel. Therefore, the volume shrinkage and wire shrinkage are large during casting, which is prone to stress and crack.
In order to improve the performance of high manganese steel, many studies have been made on alloying, microalloying, carbon and manganese content adjustment and precipitation reinforcement treatment, and they are applied in the production practice. The appearance of mesostatic austenitic manganese steel can greatly reduce the carbon and manganese content of the steel and improve the deformation and reinforcement speed of the steel, which can be applied to the working condition of high and low impact load, which is the new development of high manganese steel.
(2) No magnetic steel. This kind of steel contains more than 17% manganese, and the carbon content is generally less than 1.0%, and it is often used in the motor industry to make protective rings. The density of this type of steel is about 7.87~7.98g/cm3. Due to the high content of carbon and manganese, the thermal conductivity of steel is poor. The thermal conductivity is 12.979W/ (m ℃), about 1 / 3 of the carbon steel. Because the steel is austenitic tissue and has no magnetic properties, its magnetic conductivity μ is 1.003 to 1.03 (H/m).
