Cryogenically assisted manufacturing processes are emerging as environmentally-benign, toxic-free, hazardless operations, producing functionally superior products. This paper presents an overview of major cryogenic manufacturing processes, summarizing the state-of-the-art and significant developments during the last few decades. It begins with a summary of historic perspectives, including definitions, scope, and proceeds to analysis of process mechanics and material performance covering tribological and thermo-mechanical interactions, followed by surface integrity, product quality and performance in cryogenic manufacturing. Process analysis and applications includes machining, forming and grinding. Economic, safety and health issues are then discussed. Finally, progress in developing predictive performance models and future outlook are presented.

Cryogenic manufacturing processes

Cryogenic treatment has been claimed to improve wear resistance of certain steels and has been implemented in cutting tools, autos, barrels etc. Although it has been confirmed that cryogenic treatment can improve the service life of tools, the underling mechanism remains unclear. In this paper, we studied the microstructure changes of M2 tool steel before and after cryogenic treatment. We found that cryogenic treatment can facilitate the formation of carbon clustering and increase the carbide density in the subsequent heat treatment, thus improving the wear resistance of steels.

Microstructure of cryogenic treated M2 tool steel

Application of sustainable techniques in metal cutting for enhanced machinability: a review

Effect of cryogenic treatment on the mechanical properties of 4340 steel

Enhancing the wear resistance of case carburized steel (En 353) by cryogenic treatment

The wear resistance of an Fe-12.2wt%Cr-0.84wt%Mo-0.43wt%V-1.44wt%C alloy tool steel after cold treatment at 223K (subzero treatment) and after cryogenic treatment 93K (ultra-subzero treatment) has been investigated. The wear resistance of steels after cryogenic treatment is superior to that after cold treatment. The effects of cryogenic treatment on the microstructure were also studied by means of X-ray diffraction and transmission electron microscopy methods. Unlike cold treatment, cryogenic treatment improves the preferential precipitation of fine η-carbides instead of e-carbides. These fine carbide particles enhance the strength and thoughness of the martensite matrix and then increase the wear resistance. The formation mechanism of fine η-carbide is discussed.

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Role of Eta-carbide Precipitations in the Wear Resistance Improvements of Fe-12Cr-Mo-V-1.4C Tool Steel by Cryogenic Treatment

Wear processes greatly reduce precision and the service duration of bearings. Subzero treating techniques have been used to improve wear resistance of materials for many years. In the previous paper, the authors definitively divided the subzero treatment into a cold treatment and a cryogenic treatment according to the negative treating temperature. It is widely accepted that cold treating temperature is sufficient to fully transform any retained austenite into martensite which is considered to be a major factor to improve wear resistance. However, more recent evidence has shown that wear resistance is further enhanced by a cryogenic treatment. Despite the numerous practical successes of a subzero treatment and research projects undertaken worldwide, no conclusive metallurgical understanding on this treatment has been established. In this paper, the wear resistance and microstructure of a bearing steel resulting from cold and cryogenic treatments is studied.

Fanju Meng

Papers

Role of Eta-carbide Precipitations in the Wear Resistance Improvements of Fe-12Cr-Mo-V-1.4C Tool Steel by Cryogenic Treatment

Wear resistance and microstructure of cryogenic treated Fe-1.4Cr-1C bearing steel

Bond Behaviors of Bfrp Bars in Concrete Using Carbon Fiber Rib Anchorage