Metallographic diagram of Cr12 (rubbing plate) quenched at 980°C

Introduction

Mobile phones and televisions are widely used in our daily life, but few people have actually stopped to think about the production process of these products and the materials that are used. Cr12 steel ( also known as cold work die steel or roller steel) is an important material used in the production of mobile phones, televisions and other electronic products due to its excellent wear and corrosion resistance properties. In order to improve the performance and quality of product, it is necessary to carry out the heat treatment on the Cr12 steel. This paper describes the heat treatment process of Cr12 steel and its microstructure after heat treatment at 980 ° C.

Cr12 Steel Heat Treatment Process

The heat treatment process of Cr12 steel consists of three main steps, preheating, quenching and tempering. Preheating is the process of gradually heating the steel to a certain temperature (the preheating temperature for Cr12 steel is 800-1000°C). During preheating, the structure of the steel such as crystal boundaries and grain boundaries, strengthen and the steel properties such as hardness and strength improve. The next step is quenching, which involves quickly cooling the steel in a liquid, usually water or oil. This process transforms the steels structure into an austenite phase and increases the hardness of the steel. The final step is tempering, which is the process of reheating the steel to a lower temperature in order to further reduce the hardness of the steel and improve its ductility and toughness.

Microstructure of 980°C Heat-treated Cr12 Steel

The microstructure of 980°C heat-treated Cr12 steel is composed of a large number of lath shape martensite and some retained austenite. Through optical microscope observation can find that their small grains are uniform and dense, and the grain boundaries are distributed clearly, the martensite and retained austenite are in a reasonable distribution. The martensite lath crystals are densely arranged, arranged in blocks and intertwined, with the grain size of about 5-6μm. Retained austenite is distributed in the form of nets, and the composition and arrangement of retained austenite are reasonable.

Conclusion

Heat treatment is a very important process in the production of electronic products in order to improve their internal structure and ensure good performance. This paper analyzed and discussed the 980 °C heat treatment of Cr12 steel, which is an important material used in the production of mobile phones, televisions and other electronic products. The results show that the microstructure of the Cr12 steel after heat treatment is composed of a large number of lath shape martensite and some retained austenite, and the grain size of martensite is about 5-6μm. In addition, the retained austenite is distributed in the form of nets, and the composition and arrangement of retained austenite are reasonable. The information provided in this paper can be used as a reference for the further study of heat treatment of Cr12 steel.

High-chromium cold work tool steel is one of the important conventional cold work tool steels, which is widely used in all walks of life.The most common grade is Cr12.Cr12 cold work tool steel contains high carbon, chromium and a certain amount of molybdenum and vanadium elements, which have high strength and good hardenability.Under quenching and tempering treatment, the hardness can be high to HRC60-64, and the dimensional stability is excellent.

Cr12 cold work tool steel usually needs to be quenched by oil or air, and then tempered at a temperature of 980 °C in order to ensure that its hardness and wear resistance reach the best state.The microstructure at this temperature is composed of martensite, retained austenite and a small amount of carbides.In addition, the fully martensite microstructure of Cr12 after quenching and tempering at 980 °C has a relatively uniform carbide distribution, so that its cutting performance and wear resistance can be improved.

Therefore, in the actual tool manufacturing industry, the steel of Cr12 is often used.In order to get better quality, the quenching and tempering at 980 °C is required.At this temperature, the microstructure contains martensite and a certain amount of retained austenite, as well as a small amount of carbide distributed evenly, which can improve its cutting performance.