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

2010 ◽  
Vol 210 (14) ◽  
pp. 1949-1955 ◽  
Author(s):  
A. Oppenkowski ◽  
S. Weber ◽  
W. Theisen
2020 ◽  
Vol 1012 ◽  
pp. 331-336
Author(s):  
Marcelo Nava ◽  
Pedro Cunha de Lima ◽  
Emmanuel Pacheco Rocha Lima

Deep cryogenic treatment (DCT) is industrially applied to improve the wear resistance characteristics of tool steels. However, on non-ferrous metals, the knowledge about the obtained characteristics after DCT is limited. The purpose of this work was to investigate how DCT affects the properties and the behavior of the Cu-14Al-4Ni alloy treated at different times and after thermomechanical cycling was performed. In the present investigation, there was performed a comparative experimental analysis of the transformation temperatures, microhardness and shape recovery capacity of the alloy obtained by smelting, treated by DCT and thermomechanically cycled. The DCT provided the stabilization of the martensitic phase β'1 and, consequently, the stabilization of the phase transformation temperatures and the shape recovery capacity of the shape memory effect of the alloy, increasing the alloy life.


Author(s):  
Debdulal Das ◽  
Kalyan K. Ray ◽  
Apurba K. Dutta

This study examines the influence of different sub-zero processing routes on microstructure and mechanical properties of a cold work tool steel. Incorporation of controlled sub-zero processing cycle in between hardening and tempering treatment of tool steels increases the amount of ultrafine carbide particles with improved homogeneous distribution in addition to reduction in retained austenite content; these modifications are found to be enhanced with decreasing lowest temperature of the sub-zero processing cycle. It has been demonstrated that with reference to conventional heat treatment, sub-zero processing moderately improves hardness and marginally reduces fracture toughness but substantially enhances wear resistance of the selected steel; the extent of variations, in general, increase in the order of cold treatment, shallow cryogenic treatment and deep cryogenic treatment. The relationships of microstructural modifications with the variations of mechanical properties of tool steels due to different sub-zero processing have been established.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1038 ◽  
Author(s):  
Pello Jimbert ◽  
Maider Iturrondobeitia ◽  
Julen Ibarretxe ◽  
Roberto Fernandez-Martinez

The effects of deep cryogenic treatment (DCT) on the wear behavior of different tool steels have been widely reported in the scientific literature with uneven results. Some tool steels show a significant improvement in their wear resistance when they have been cryogenically treated while others exhibit no relevant amelioration or even a reduction in their wear resistance. In this study, the influence of DCT was investigated for a grade that has been barely studied in the scientific literature, the AISI A8 air-hardening medium-alloy cold work tool steel. Several aspects were analyzed in the present work: the wear resistance of the alloy, the internal residual stress, and finally the secondary carbide precipitation in terms of lengths and occupied area and its distribution into the microstructure. The results revealed a reduction in the wear rate of about 14% when the AISI A8 was cryogenically treated before tempering. The number of carbides that precipitated into the microstructure was 6% higher for the cryogenically treated samples, increasing from 0.68% to 0.73% of the total area they covered. Furthermore, the distribution of the carbides into the microstructure was more homogenous for the cryogenically treated samples.


Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 564 ◽  
Author(s):  
Maider Muro ◽  
Garikoitz Artola ◽  
Josu Leunda ◽  
Carlos Soriano ◽  
Carlos Angulo

Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in the die, but exhibit poor wear performance owing to the lack of carbides in their structure. This drawback can be overcome by combining laser cladding technology, austenite retention, and cryogenic treatments. Hence, an alternative die manufacturing route based on laser cladding was explored. The forming surface of a modified chemistry tool steel die was subjected to cladding. The martensite finish (Mf) temperature of the steel was tuned to enhance austenite retention at room temperature. The cladded surface was then machined in a reduced-hardness condition resulting from retained austenite formation. Subsequent deep cryogenic treatment of the die favoured the retained-austenite-to-martensite transformation, thereby increasing the die hardness without major distortion or oxidation. This process combined the advantages of high-carbide-bearing tool steels and PH steels, allowing for a die with hardness exceeding 58 HRC to be finish machined at <52 HRC. Controlling the occurrence of retained austenite represents an effective strategy for achieving new manufacturing scenarios.


2001 ◽  
Vol 118 (1-3) ◽  
pp. 350-355 ◽  
Author(s):  
A. Molinari ◽  
M. Pellizzari ◽  
S. Gialanella ◽  
G. Straffelini ◽  
K.H. Stiasny

2010 ◽  
Vol 117 ◽  
pp. 49-54 ◽  
Author(s):  
Debdulal Das ◽  
Apurba Kishore Dutta ◽  
Kalyan Kumar Ray

This study aims to reveal the underlying mechanism associated with the enhancement of wear resistance of tool steels by deep cryogenic treatment and to resolve the issue of reported varied degree of improvement in wear resistance through structure-property correlation of cryotreated vis-à-vis conventionally treated AISI D2 steel. Microstructures of heat treated specimens have been characterized employing various techniques with specific emphasis on quantitative estimation of the characteristics of secondary carbides. Evaluations of properties include measurements of bulk hardness, apparent strength of the matrix, fracture toughness and dry sliding wear resistance under wide rage of normal loads supplemented by in-depth characterizations of worn surfaces, wear debris and subsurfaces of worn specimens in order to identify the operative mode and mechanism of wear. It has been demonstrated that the favorable modifications of the precipitation behavior of secondary carbides in addition to removal of retained austenite are the governing mechanisms for the enhancement of wear resistance of tool steels by deep cryogenic treatment. The cause of the reported varied degree of improvement in wear resistance by deep cryogenic treatment has been explained by disparity of the operative modes and mechanisms of wear.


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