In recent years, in terms of hot work mold materials, austenitic stainless steel has been introduced and applied more and more widely because of the requirements of high temperature resistance, corrosion resistance and oxidation resistance. Because austenitic stainless steel usually contains austenite-forming elements such as nickel and manganese, and some also add a certain amount of carbon, chromium and other elements, these will make the austenite structure more stable, which is beneficial to heating and cooling. There will be no phase change during the process, that is, the high temperature strength and heat resistance are very high.

However, austenitic stainless steel has the disadvantages of large linear expansion coefficient and weak thermal conductivity, which weakens the thermal fatigue performance of the material, so it is not suitable for mold selection that will undergo strong water cooling.

4Cr14Ni14W2Mo austenitic stainless steel has excellent mechanical properties below 650℃; at 600-800℃, it is easy to be strengthened due to strong aging; below 800℃, it will be heat-resistant and does not peel; below 900℃ The gas corrosion resistance is better at ℃. The heat treatment process of austenitic stainless steel is water cooling at a solid solution temperature of 1000-1100°C, and the metallographic structure is austenite; the aging treatment temperature is 750°C, air cooling, and the structure is austenite.

In addition, this steel type also has relatively good oxidation resistance and can be used to form hot work molds such as creep forming molds, highly corrosive glass forming molds, and die-casting cores.

Austenitic stainless steel can also be used in non-magnetic molds. In order to adapt to the production of magnetic products, non-magnetic mold steel is usually used to manufacture non-magnetic cold work molds and plastic molds. This kind of mold will not be magnetized in a strong magnetic field, which can ensure that even if the magnetic products are magnetized during the production process, they will still remain intact. It will be easy to demould, which can effectively ensure the normal production.

Non-magnetic mold steel materials mainly include austenitic stainless steel and high manganese steel. Among them, 1Cr18Ni9Ti steel is an austenitic stainless steel, which has good resistance to intergranular corrosion, can maintain a stable austenite structure under various conditions, and will not generate magnetic induction in a strong magnetic field.

The annealing temperature of the cold drawn billet of this austenitic stainless steel is 970℃, water cooling; the solution treatment temperature is 1030-1160℃ water cooling, the structure is austenitic; the aging temperature is 800℃ holding for 10h or the aging temperature is 700℃ holding for 20h, the structure It is austenite and magnetized. After aging, the strength and other mechanical properties are improved, but the hardness is still relatively low. In order to ensure the wear resistance of the material, corresponding nitriding treatment is usually required.

Since 1Cr18Ni9Ti austenitic stainless steel has a single-phase austenite structure after solid solution, it will not form induction in strong magnetism, and is suitable for the production of non-magnetic molds and plastic molds requiring corrosion resistance.