Investigation of phase structure of cobalt and its effect in WC–Co cemented carbides before and after deep cryogenic treatment

Author(s):  
M. Padmakumar ◽  
J. Guruprasath ◽  
Prabin Achuthan ◽  
D. Dinakaran
2020 ◽  
Vol 403 ◽  
pp. 75-89
Author(s):  
Vojtěch Průcha ◽  
David Bricín ◽  
Antonín Kříž ◽  
Zdeněk Jansa

The present paper explores the effects of deep cryogenic treatment (DCT) on the properties of WC-Co cemented carbides. The investigation involved four different cemented carbide (CC) grades. Two of them were coarse-grained WC with grain sizes larger than 6 μm and binder fractions of 10 and 15 wt. %. The other two were fine-grained with WC grains of 0.5-0.8 μm and the same binder fractions of 10 and 15 wt. %. Their specimens were ground and polished to prepare them for DCT. In each specimen, one half of this polished surface was used for testing the properties of the CC before cryogenic treatment. The post-DCT properties were then determined on the other half. Properties of the cemented carbides prior to and after DCT were studied using optical and scanning electron microscopy, X-ray diffraction, hardness testing according to Vickers scale followed by calculation of fracture toughness KIC and a ball-on-disk test of the wear resistance of the surface. One of the findings was that cryogenic treatment led to a decrease in residual stresses and to lower fracture toughness KIC in the CC.


2010 ◽  
Vol 139-141 ◽  
pp. 702-705 ◽  
Author(s):  
Hong Juan Yan ◽  
Hong Hai Xu ◽  
Xin Min Li

Deep Cryogenic treatment (DCT) is a one time permanent process, carried out in such a way that the material is slowly cooled down to the cryogenic temperature, after which it is held at that temperature for a specified period of time and is heated back to room temperature at slow rate followed by low temperature tempering. In this study, the orthogonal experiment method was used to study the DCT process of YT30 cemented carbide inserts. The primary relation of the different factors of DCT was analyzed. TH300 sclerometer was used to measure the hardness of inserts. The microscopes were used to observe the wearing profiles of inserts and microstructures before and after DCT. The orthogonal experiment results show that the effect of soaking temperature on the properties of inserts is the first factor, the soaking time is second one, the cooling rate is third one, and the last one is the tempering temperature. DCT improves the multi-type martensite transformation of Co. Therefore DCT increases hardness and enhance wear resistance of the cemented carbide inserts.


2011 ◽  
Vol 314-316 ◽  
pp. 927-931 ◽  
Author(s):  
Shan Gao ◽  
Zhi Sheng Wu ◽  
Peng Fei Jin ◽  
Jun Jie Wang

In this paper, some deep cryogenic treatment experiments are first applied to 5A06 aluminum alloy welded joint at liquid nitrogen temperature (-155°C )for 4h, 8h, 10h respectively. 5A06 alloy welded joints before and after deep cryogenic treatment are observed by X-ray diffraction and scanning electrical microscopy. The experimental results have shown that the deep cryogenic treatment causesβphase of alloy to disperse and makes the grain smaller than that of joint before deep cryogenic treatment. Therefore, the mechanical properties of 5A06 alloy welded joints after deep cryogenic treatment are greatly improved.


2010 ◽  
Vol 97-101 ◽  
pp. 457-460 ◽  
Author(s):  
Hong Juan Yan ◽  
Hong Hai Xu ◽  
Ying Liu

The Deep Cryogenic Treatment(DCT) process of W4Mo3Cr4VSi HSS was studied by orthogonal experiment method. The paper analysed the effect of various DCT process parameters on mechanical properties and observed microstructure before and after DCT treatment by the SEM. The results show that the effect of soaking temperature on the properties of drill is the first factor, the soaking time is second and the cooling rate is third. DCT enhances the transformation of austenite to martensite, and distributable carbide particles are precipitated from martensite. Therefore DCT increase hardness and enhance wear resistance of twist drill.


Author(s):  
M. Franklin ◽  
P. Perumal ◽  
P. Keerthi Vasan

Heat treatment process is a resultant process to improve the mechanical and metallurgical properties of the material. Deep cryogenic treatment is not an alternative process to the heat treatment process it is a complimentary process to the heat treatment and it affects the entire cross section of the material. Deep cryogenic treatment is a heat treatment process where the material is subjected to comparatively extreme low temperature condition in order to enhance the mechanical and metallurgical behaviors of the material. Low alloyed case hardening steels used for manufacturing of parts which required to withstand high operating condition such as axle drives, gears & shafts. In this proposed work 20MnCr5 steel has been subjected to Deep Cryogenic Treatment at different soaking temperature and period. A comparative characterization study has to be conducted, before and after the cryogenic treatment, to investigate the behavior of materials.


2021 ◽  
Vol 548 ◽  
pp. 149257
Author(s):  
Patricia Jovičević-Klug ◽  
Monika Jenko ◽  
Matic Jovičević-Klug ◽  
Barbara Šetina Batič ◽  
Janez Kovač ◽  
...  

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