Nickel is an alloying element that stabilizes austenite in steel. Nickel's main role in high manganese steel as follows:
1) Nickel can inhibit the desolubilization of carbon from austenite, reduce the precipitation tendency of grain boundary carbides, and significantly reduce the number of intergranular carbides. Nickel-containing high manganese steel uses normalizing instead of water quenching to obtain a single austenite structure, which will greatly reduce the occurrence of casting deformation and cracks caused by water quenching and simplify production equipment.
2) Nickel can significantly improve the low temperature mechanical properties of high manganese steel. The impact toughness of 1%C-12%Mn high manganese steel at -40°C is only 57% of the room temperature value. After adding 3% nickel by mass, this ratio increases to 75%. The zero plastic transition temperature (NDTT) of conventional high manganese steel is -93℃, which can be reduced to below -100℃ after adding nickel, and when the mass fraction of nickel is below 5%, the low temperature impact toughness of high manganese steel increases with the increasing content nickel content .
3) Nickel can increase the use temperature of high manganese steel and expand the application range. The heat-treated ordinary high-manganese steel starts to precipitate needle-like carbides in the austenite when heated to 260°C, resulting in a corresponding increase in the brittleness of the material. The addition of 3% nickel in high manganese steel can increase the precipitation temperature of carbides to 380°C.
4) Nickel can improve the oxidation resistance of high manganese steel. The carbides in the as-cast structure of nickel-containing high-manganese steel are small in size and quantity, the austenitizing temperature can be reduced to about 950℃, and the holding time can be shortened accordingly. Furthermore, the nickel-containing castings themselves have better oxidation resistance. As a result, the amount of decarburization and oxide scale formation of nickel-containing high manganese steel castings after heat treatment is greatly reduced, and the quality of the castings is significantly improved.
In addition, nickel-containing high-manganese steel also has good crack resistance. Nickel can improve the welding performance of high manganese steel.
the high manganese hammer welded by our PTA powder: with longer service life
