Quenching steel and carburising steel

Quenching and carburising are generally considered to be effective methods of hardening steel. However, there are significant differences between the two processes in terms of chemical composition, properties, processing and application scenarios. This article will analyse the characteristics and differences between Quenching and carburising steel.

What is quenching steel?

Quenching steel is a steel material that has been quenched to obtain high hardness, high strength, and wear resistance. Quenching is to heat the steel to above the critical temperature, keep it at this temperature for a certain period of time, and then cool it at a cooling rate greater than the critical cooling rate, so as to obtain an unbalanced structure dominated by martensite (it may also obtain bainite or maintain single-phase austenite). The hardness of quenching steel is usually greater than HRC50, and it is often used to manufacture parts that require high durability and fatigue resistance, such as tools, molds, bearings, springs, etc.

Chemical composition

The composition of quenching steel varies depending on its use, but in general, quenching steel has a low carbon content, usually below 0.3%, and also contains elements such as chromium, nickel, molybdenum, and vanadium to improve its heat treatment properties and corrosion resistance.

Properties

The material exhibits elevated levels of hardness, with a hardness after quenching greater than HRC50. This property is accompanied by excellent wear resistance.

Additionally, the strength of steel is significantly enhanced following quenching treatment.

It is also notable for its minimal plasticity, which significantly reduces the tendency for chip accumulation during the cutting process. This, in turn, results in a machined surface that exhibits reduced surface roughness.

It should be noted that a high cutting force is required during the cutting process, and the cutting temperature is also high.

However, the material exhibits a high degree of brittleness, which can lead to breakage and wear of the cutting edge during the cutting process.

Additionally, the low thermal conductivity of the material hinders effective heat dissipation during the cutting process, thereby increasing the difficulty of the cutting operation.

Application

Quenching steels are extensively utilized in the fabrication of critical components for a range of high-performance industrial equipment and tools, including:
Tool steels, for instance, are utilized in the fabrication of cutting tools, molds, and measuring tools, exhibiting elevated levels of hardness and wear resistance.
Additionally, in the field of moulding, the material finds application. These are utilized in the fabrication of blanking, cold punching, and drawing dies, among other applications, exhibiting exceptional wear resistance and dimensional stability.
Additionally, quenching steels find application in bearings and springs. These components are engineered to withstand high levels of durability and fatigue resistance.

The difference between two steel

The treatment process for quenched steel involves the application of heat and rapid cooling, thereby altering the steel’s properties. In contrast, carburised steel undergoes a carburisation treatment, which modifies the chemical composition of the steel surface with the objective of achieving property alterations.

Performance characteristics: quenching steel undergoes a substantial increase in hardness after treatment, primarily to meet the requirements for high hardness and strength; carburising steel maintains internal toughness based on the surface hardening treatment, ensuring the surface retains high hardness.

Application areas: quenching steel finds extensive use in a variety of engineering structures and the manufacture of mechanical parts; and carburising steel is more commonly used in the manufacture of those parts that require surface hardness and internal toughness, such as gears, bearings and so on.

Conclusion

Quenching and carlmrzing steels differ in terms of the process treatments they undergo, their performance characteristics, and the areas of application in which they are used. The process of quenching is employed in the manufacture of quenching steels, with the objective of enhancing both the overall hardness and strength of the resultant material. In contrast, the focus of carlmrzing steels is on surface hardening while ensuring the retention of toughness at the internal level. The purpose of these treatments is to enhance the properties of the steel in order to satisfy the diverse engineering requirements.