15CrMo (1100℃×20min water quenching) metallographic diagram

15CrMo Alloy Steels

15CrMo alloy steels are a type of low-alloy steel containing chromium and molybdenum, with a relatively high content of carbon. This combination of elements gives the alloy steel its strength and corrosion resistance. 15CrMo alloy steel is typically used in heat-treatment applications such as quenching and tempering, as well as in certain high-temperature environments.

Heat Treatment Process

The heat treatment process of 15CrMo alloy steel typically involves quenching, tempering, and sometimes austenitizing. Quenching is the rapid cooling of the steel to further harden its components. This process can be done by immersing the steel in water or oil to cool it quickly. Tempering follows on from quenching and helps to further strengthen the steel and increase its toughness. Austenitizing is the process of heating the steel to a critical temperature and then allowing it to cool gradually. This process helps to form a stable, homogenous microstructure that provides enhanced strength and ductility.

Metallurgical Properties

15CrMo alloy steel is known for its superior strength and toughness. The alloy achieves its strength primarily through its high carbon content of around 0.70% – 1.15%. This high carbon content gives the alloy its superior strength properties, making it suitable for applications where strength and durability are key. The molybdenum content of the alloy helps to improve its ability to resist corrosion, making it suitable for use in high-temperature environments.

Hardness and Workability

15CrMo alloy steel typically has a hardness of around 39 hrc, which is relatively high compared to other types of steel. This high level of hardness makes it ideal for applications where strength and wear resistance are important. The high level of hardness also makes the steel difficult to machine, but this can be mitigated by using a different heat treatment cycle, such as austenitizing, quenching, and tempering.

Conclusion

15CrMo alloy steel is a low-alloy steel containing chromium, molybdenum, and a high carbon content. This combination of elements gives the alloy steel its superior strength and corrosion resistance. 15CrMo alloy steel is typically used in applications requiring strength and wear resistance, such as heat-treatment applications. The steel can be heat-treated by either quenching and tempering, or austenitizing, to provide a microstructure that enhances the strength and ductility of the alloy. The heat-treated alloy steel typically has a hardness of around 39 hrc, making it suitable for applications where strength and wear resistance are important.

15CrMo is a kind of low-alloy heat-resistant steel that is heated by 1100℃× 20 minutes of water quenching. It has good wear resistance and creep resistance, good process performance and high temperature oxidation resistance. In addition, it has excellent welding performance and can be used in the manufacture of structural parts of boilers and high temperature pressure vessels.

The microstructure of 15CrMo after water quenching is martensitic structure. The martensitic structure of 15CrMo is mainly composed of martensite and small amount of ferrite, with a certain amount of pearlite, which forms a tempered martensite or tempered sorbite structure. Under optical microscope, a few small particles of carbide are distributed in the martensite matrix, which is beneficial to obtain higher strength and toughness. The size of the carbide particles is generally between 0.02-0.1μm.

In metallographic inspection, it is found that the carbide form of 15CrMo is mainly lath carbide.} In scanning electric microscope (SEM), it can be seen that the carbide distributed in the matrix of 15CrMo is mainly lamellar type, and the lamellar carbide mainly contains two categories of mixed crystal lattice type and isomorphy type. In addition, there are other mixed lamellar or fibrous carbides that are less visible. It can be seen that the microstructure of 15CrMo after water quenching is relatively complex, but it also has its advantages.

In conclusion, 15CrMo is a kind of low alloy heat-resistant steel with excellent performance after water quenching. The martensitic microstructure is mainly composed of martensite, ferrite and pearlite, and the distribution of carbide is mainly lamellar type. Therefore, it has good wear resistance and creep resistance, good process performance and high temperature oxidation resistance, and excellent welding performance.