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Gears and Transmission Elements
Many of the regular applications of cryogenic treatments lie in the field of machining tools. Those used for the manufacture of gears (hobs, shaping cutters, broaches, shavers, etc.) are particularly complex and expensive as they are often designed and manufactured for a specific reference. On the other hand, gear cutting is delicate but hard work for the tools, which means they need to be sharpened continuously.
Although cemented carbide is used in some cases, most of these tools are manufactured with high speed steel due to their lower cost and, above all, their greater toughness. Nowadays the search for better performance has led to powder metallurgy steel being the most commonly-used option. Likewise, the use of PVD coatings is very common for any tool of this type used for manufacturing large series.
The CRYOBEST® multi-stage cryogenic process is particularly effective on this kind of tools as both conventional and powder metallurgy high speed steel usually respond very well to the process. We must not lose sight of the fact that the treatment is applied just once and it permanently affects the entire volume of the tool. The more times the tools need to be sharpened (and recoated), the greater the benefits.
At Cryobest we commonly treat tools such as hobs, shaping cutters, broaches, inserts, etc. used in the manufacturing of transmission elements with very good results. As can be seen in the examples of application, multi-stage cryogenic treatment is an easy but effective way of achieving significant cost reductions and increases in productivity in this sector.
Apart from what we have mentioned for tools, this technology also has great potential to improve the performance of materials used in the manufacturing of transmission elements such as case carburized steel. We must not forget that these components are designed to withstand great efforts and the properties of the material used to manufacture them are a decisive factor in order to achieve the desired performance and reliability. The resistance to wear and fatigue are two characteristics that can improve significantly with the CRYOBEST® process, but positive effects can also be achieved in the resistance to pitting, heat dissipation, dimensional stability, resistance to corrosion, etc.
As with other technologies, cryogenic treatments are reaching this type of applications through motor racing. This type of process is becoming popular, mainly in the US, because it notably improves the performance and reliability of clutches, brake rotors, springs, engine blocks, cylinder heads, pistons, bearings, crankshafts, rods, etc. and, of course, transmission elements (gearboxes, differentials, axles, pinions, etc.)
Apart from the empirical evidence, over the last few years various different studies have been carried out on the effects of cryogenic treatments on case carburized steel which confirm the beneficial effect of this type of processes on the hardness, wear resistance, bending strength, rolling contact fatigue and the fatigue limit of the material. On the other hand, thanks to the reduction of remaining austenite, the dimensional stability is higher, which is very important in order to prevent noise problems in precision gears.
The CRYOBEST® process is a cost-effective and environmentally friendly way to increase the performance and reliability of the transmission elements. If it is taken into account from the design phases, it can also be a valuable tool to achieve significant size and weight reductions in this type of component.
> Examples of Applications
