Cryogenic treatment of metallic materials

When we talk about heat treatments, the first thing that comes to mind is ovens and high temperatures. However, it must be taken into account that the ambient temperature is about 300 K, still quite far from absolute zero. Despite what it may seem at first glance, if the temperature of a material is reduced there is still a wide margin in which microstructural changes could be triggered.

This possibility has not been explored until relatively recently because truly low temperatures do not exist in nature and could only be achieved when, at the end of the 19th century, the liquefaction of air and its main constituents (nitrogen -196 ºC) was achieved. ; oxygen -183 ºC). Although there have been experiences related to the effect of cryogenic temperatures on materials since the beginning of the 20th century, we cannot speak of a cryogenic treatment industry itself until just a couple of decades ago. Still little known in Europe, its development and implementation are rapid throughout the world.

There are many materials whose characteristics can be altered by low temperatures: metals (steel, hard metal, cast iron, copper, aluminum, magnesium alloys, etc.), ceramic materials and even some polymers. Obviously the effects depend on the material considered, with the most common being related to wear resistance and fatigue life, but also to conductivity, toughness, residual stresses… However, the mechanisms behind them are still not well known. the changes that cryogenic temperatures cause in materials. This is because it is a relatively recent technology and many of the applications have been developed primarily empirically.

Among the common application examples of this technology are all types of tools or consumables that must be replaced as a result of wear or fatigue, such as, for example, machining tools (drills, milling cutters, inserts, reamers, broaches…), blades, punches, dies, molds, rollers, etc. However, it is possible to find examples in practically any sector: metalworking, automotive, aeronautics, forestry, mining, electronics… Where there is a problem with the durability of the material, there may be an opportunity for this type of process.

One of the characteristics of cryogenic treatments is that, like other thermal treatments, they are processes that permanently affect the entire volume of the piece, that is, they are not superficial. This means that, for example, a blade that has been cryogenically treated can be sharpened as many times as desired without losing its performance.

On the other hand, cryogenic treatments are also compatible with surface treatments and anti-wear coatings common in the industry.

It is also worth noting that it is a completely environmentally friendly technology since, during its process, cryogenic treatments do not produce absolutely any type of discharge or waste.

It is, therefore, a technology with enormous development potential. Azterlan has opted for it and has created a new department equipped with the necessary human and technical resources to be able to conduct in-depth research into the response of various materials to cryogenic treatments as well as their industrial applications. Not only that, since it also has two industrial cryogenic processors capable of treating, each, more than 600 kg per load. With them, Azterlan is providing cryogenic treatment services to numerous companies. Some of them are foreign and, in all cases, they are benefiting from the reduction in their manufacturing costs or from the improvement in the performance of their products.

There is no doubt that this technology has a great future but, fortunately, it is not necessary to wait, since cryogenic treatments are available to companies that want it. They are a simple, ecological and efficient way to improve the performance of materials.