Through a collection of metal working and industrial procedures, the heat treatment process is used to bring tool steel to a hardened state. The correct hardness depends on the application of the steel being treated. Knives need to be hard enough to hold a sharp edge through continuous mechanical abrasion yet be soft (flexible) enough to stand up to forceful use without breaking.
There are several different heat treatment techniques you can utilise in order to ensure superior quality – namely hardening, quenching and tempering. Through a combination of these techniques the blade is made stronger and more resistant to impact, or alternatively is made more malleable or ductile.
Heating the metal must be done in a uniform way because if the metal blade is unevenly heated then distortion or cracks may occur. Once the material is hardened and strengthened, quenching must take place. This technique refers to aggressively cooling a material by the use of oil, water, and air and returning it to room temperature. Quenching halts low-temperature processes and introduce martensite (a very hard form of steel crystalline structure), which hardens the material. However, this step also makes the blade or knife very hard and produces extremely high internal stresses.
To combat this and relieve internal stresses, the blades undergoes tempering after quenching. This technique involves reheating the metal, maintaining this temperature for a specific period of time and letting it cool once more. This reheating is done at a temperature that is much lower than when hardening. The higher the tempering temperature used, the softer the metal becomes. Some materials need more than one tempering cycle in order to refine the micro-structure, improve wear properties and increase elasticity.
The heat treatment process is a complicated one that is a collection of metal working and industrial processes. Through the use of controlled heating and cooling operations, industrial blades and knives can be honed to perfection by improving the structural and physical properties. At Zanogen, we understand the complexity and importance of the heat treatment process. As such, all stages of the manufacturing process take place within our own factory premises, including heat treatment. Get in touch today to find out how Zanogen can provide you with industrial plastic and recycling blades that are heat treated in-house ensuring superior quality.