Are you familiar with the techniques of quenching and tempering?

The main objective of heat treatment is to modify the structure of steel. With heating and cooling processes, it is possible to achieve, at different times and conditions, all the possibilities of this element. However, to reach its full potential, some steps, such as quenching and tempering, cannot be left out.

Here at Cutelaria Cimo, we are passionate about knives and the sharp world. Just as our fascination transcends the barriers of usability, we also believe in the importance of knowing their manufacturing processes. Understanding how these steps develop and what results they can offer for steel is truly amazing.

To understand how these microstructures behave, and how quenching and tempering and their companions can alter the natural conditions of steel, it is important to understand how their phases work. Check out the practical guide that Cimo has prepared for you and come learn about the curiosities of cutlery with us!

Is there a difference between quenching and tempering?

Before meticulously learning the details of each stage of quenching and tempering in the transformation of steel, it is important to answer one of the main questions about these heat treatments. If you have ever wondered about the difference between these two moments, know that they are not that far apart.

Tempering is responsible for gradually reducing the mechanical resistance and solidity obtained during the quenching process, that is, it is one of the stages of this main procedure. With it, it is possible to make the steel malleable, but with a high level of toughness. Ideal for the production of knives, pocketknives, and other cutlery objects.

Before finishing quenching, tempering comes into play to produce a superior metal for knives and other survival tools or rural life. With processes such as annealing or normalization, it is possible to improve the results guaranteed by quenching and provide higher quality products to consumers.

Even if not all metals are suitable for contact with the tempering process, or with tempering, it is valid to understand that these two stages work together. For a complete heat treatment, it is essential to use both phases.

Quenching and heat treatment procedures

Using quenching as the thermal procedure to treat metals and materials for knives is a very important differential to ensure quality products. With it, more strength is guaranteed through heating and faster and more effective cooling in the transformation of steel.

To begin, the steel part is taken for heating in the induction quenching process. In the furnace, each type of steel will reach a specific temperature, and the final result only appears when the reorganization of the metal crystals is complete. This method is called austenitization.

The second part of the heat treatment by quenching is the cooling of the crystals, which happens abruptly in oils, water, or air. This speed in the cooling process is fundamental so that the steel does not lose the shapes and characteristics acquired during the first heating.

Martensite and tempering

After the stages of partial quenching procedure, the metallic crystals of carbon or iron transform into martensite. The name is associated with the state that the steel is in after heating and cooling at low temperatures. Only this state allows the necessary plasticity for the construction of molds and shapes with more rigidity.

With the martensite already prepared, it's time to start the tempering process, which plays an essential role in ensuring the complete removal of residual stresses that the quenching process may have originated. It is also responsible, as we well know, for giving more firmness and durability to all cutlery materials.

As we have already mentioned here, each type of steel requires a specific heating and cooling temperature in quenching, and tempering is no different. Before starting to reheat the parts, remember to find the most suitable range for your needs.

Small and large transformations of the martensitic structure can happen depending on this chosen interval. From 140°C to 200°C, the changes are less expressive. However, at 210°C and 260°C, the stresses begin to be modified, and tempering begins a significant alteration in the structure.

The higher the temperature, the more structural effects it can cause on your parts, and above 370°C, they can start to show coarse and visible cementites, so all attention is essential. Intervals above 730°C significantly impair the hardness of the parts; if this is not your intention, be careful!

Quenching and tempering are indispensable for shaping the construction of good cutlery pieces. Survival knives, pocketknives, barbecue options, and even household knives need to undergo a process of extreme care and observation before arriving at your home.

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