On the enhancement of wear resistance of tool steels by cryogenic treatment

Abstract

The present article aims to resolve the debate on the degree of benefit of processing tool or die steels by cryogenic treatment. This has been done by measuring transition loads for quenched and tempered die steel with and without cryogenic treatment. The wide range of reported degrees of improvement of wear resistance by cryotreatment is explained by the operative modes and mechanisms of sliding wear considering the wear rate ratio of conventionally treated to cryotreated steels on a two-dimensional map.

Evaluation of factors influencing deep cryogenic treatment that affect the properties of tool steels

“…For instance, in the case of D2 cold-work steel the improvements in wear resistance vary from about 10% (Collins and O'Rourke, 1998) up to 800% (Barron, 1982). Das et al (2008Das et al ( , 2009a explained this spread of data for the dry sliding test with a frequently lacking systematic analysis of the modes and mechanism of wear being determined with differently applied test parameters and especially the normal load. In this context, Das et al (2009a,b,c) found that the improvement in wear resistance due to DCT is much higher when the modes and mechanism of wear between conventionally and cryogenically treated specimens are dissimilar.…”

Effect of Cryogenic Treatment on Tool Steels.

“…Figure 13. TEM micrographs of M-2 steel (a) and (b) Representative regions from the same untreated sample (c) Cryotreated sample 18 In the series of experiment 22,23,24 significant precipitation of secondary carbides was observed. As in most studies of cryogenic treatments on tool steels mechanical properties have improved figure 14 shows the SEM micrographs of various cryotretment, In cryogenic treatment holding time has a significant effect on wear resistance properties.…”

Simultaneous enhancement of strength and ductility in cryogenically treated AISI D2 tool steel

“…However, in most applications of AISI D2, high strength and good ductility are simultaneously required [7][8][9][10]. Although some authors have reported wear resistance enhancement of D2 steels after cryogenic treatment [7][8][9][10], others have reported hardness improvement but toughness reduction after cryogenic treatment [20]. More work is therefore required to better understand the interrelationships between cryogenic process parameters, microstructure evolution, and mechanical properties.…”

“…The process involves cooling the materials down to liquid nitrogen temperature (77K), holding for specific time, and then heating up to room temperature (RT) followed by final tempering [4]. A number of cold work tool steels, high-speed tool steels, carburized steels, and stainless steels have been submitted to cryogenic treatments and the reports show considerable enhancement in wear resistance of these steels [6][7][8][9][10]. Despite the reported results on beneficial effects of cryogenic treatment, investigations about the fundamental mechanism governing cryogenic treatment and their effect on the microstructure of tool steels started only in late 1990's [6,[11][12][13][14][15].…”