Effect Of Deep Cryogenic Treatment Research Articles

Effect of Deep Cryogenic Treatment on the Microstructure and Corrosion Behavior of the Microarc Oxidized Mg-Zn-Ca Alloy

Effect of Deep Cryogenic Treatment on the Microstructure and Corrosion Behavior of the Microarc Oxidized Mg-Zn-Ca Alloy

Effect of deep cryogenic treatment on the mechanical properties of AISI D3 tool steel

Effect of deep cryogenic treatment on the mechanical properties of AISI D3 tool steel

Effect of deep cryogenic treatment on performance measures in wire electrical discharge machining process during taper cutting operation

Effect of deep cryogenic treatment on performance measures in wire electrical discharge machining process during taper cutting operation

Effect of deep cryogenic treatment on microstructure, mechanical properties and machining performances of coated carbide tool

Deep cryogenic treatment (DCT) has been acknowledged as an approach to modify metallic materials properties to enhance their performance. The effects of deep cryogenic treatment parameters (cryogenic temperature, cooling rate, soaking time and tempering temperature) on microstructure, mechanical properties and machining performance of Ti (N, C)–Al2O3-coated cemented carbide insert have been comprehensively investigated in this paper. First, microstructure examination results show that a decarburization phase was detected and the WC particles were refined after deep cryogenic treatment. Secondly, the hardness of the WC–Co substrate and the wear resistance of the coatings after DCT were elevated. In addition, the transformation from α-Co to e-Co was observed, which is highly dependent on cryogenic temperature and soaking time. Finally, dry milling experiments were carried out and the results indicated that the tool wear resistance was improved and the experimentally measured cutting forces had lower values using cryogenically treated insert, which can be attributed to the dissolution of Co into WC yielding microplastic deformation as well as the enhanced wear resistance. This research can provide guidance for optimizing DCT parameters of coated carbide insert to acquire desired mechanical properties and improve cutting performance.

Electrochemical behavior of Ti–6Al–4V alloy in Hank’s solution subjected to deep cryogenic treatment

The effect of deep cryogenic treatment (DCT) on the electrochemical behavior of Ti–6Al–4V alloy in Hank’s solution was experimentally investigated in the present work. Deep cryogenic treatments at − 196 °C soaking for 24 (DCT-24) and 48 (DCT-48) hours were conducted on the commercial annealed Ti–6Al–4V alloy. The methods of polarization and electrochemical impedance spectroscopy (EIS) were employed to evaluate the electrochemical behavior and corrosion mechanism. Furthermore, atomic force microscopy (AFM) was used to detect the corrosion surface. The results showed that deep cryogenic treatment shifted the corrosion potentials (Ecorr) to the positive direction. The corrosion current densities (icorr) of samples treated by DCT-24 and DCT-48 decreased from 153.1 nA·cm−2 in the untreated (UT) sample to 86.3 nA·cm−2 and 43.3 nA·cm−2, respectively. Furthermore, the roughness of corrosion surfaces of samples subjected to DCT was smaller than that of the UT sample, which indeed demonstrated the improvement in corrosion resistance of Ti–6Al–4V alloy in Hank’s solution. The results of EIS test indicated that deep cryogenic treatment had no influence on the corrosion mechanism of Ti–6Al–4V alloy in Hank’s, while enhanced resistance value of outer porous layer Rp, which makes the surface more efficient to prevent the corrosion. The reduction of β-phase particles, improvement in dislocation density and release of residual stress caused by deep cryogenic treatment had great contribution to the improvement in corrosion resistance of Ti–6Al–4V alloy in Hank’s solution.

Microstructure evolution and mechanical/physical properties of 25# valve alloys steel subjected to deep cryogenic treatment

In this work, 25# valves alloy steel was selected as the experimental material for the new generation of low temperature valves steel. Effect of deep cryogenic treatment (DCT) time and cycle number on the microstructure evolution and mechanical/physical properties of 25# alloys steel were investigated and analyzed. Experimental results show that the microstructure for the tiny lath martensite after quenching, also lamellar martensite and retained austenite were obtained after DCT. At the same time, the retained austenite transformed into tiny lath martensite microstructure. Also, the smaller dispersion of M6C carbides were precipitated and distributed in grain boundaries and thin film retained austenite with an increase of DCT time and cycles as well as formation of stacking faults. The cryogenic processing has an obvious impact on the mechanical properties of materials. The strength of the material increases firstly and then sharply decreases with DCT time and cycles number, but the strain exhibits the opposite trend. The maximum strength is 1390 MPa, which is triple the original sample with a value of 441 MPa. Also, the hardness of the materials increases remarkably with a value of 52.6 HRC, enhancement of ∼28.9% and then decreases slightly with an increase of DCT time and cycles number. The fracture mechanism is typical cup - cone - shaped ductile fracture. After DCT, the linear expansion coefficient of the material gradually decreases and then table, which is satisfied with the cryogenic valves steel at low temperature service conditions.

Wear resistance of the pressure armor submitted to deep cryogenic treatment and plasma nitriding

Risers are multilayer structures used in oil production and transportation. The pressure armor is the layer responsible for supporting the internal radial pressure and is produced from a helical interlocked steel wire. The interlocking mechanism, which gives flexibility to the riser, is responsible for the wear on the pressure armor, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear in the pressure armor. Samples tested were taken from the contact region of the pressure armor. The micro-abrasive wear test was performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 h). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient similar to the sample as received. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received and an improvement in wear coefficient in the transient (29.85%, 28.53% and 29.81%) and permanent (19.18%, 25.19% and 28.09%) regions.

Effect of Deep Cryogenic Treatment on Mechanical Properties and Microstructure of the Tool Steel CR7V for Hot Stamping

To solve the failure problem of hot stamping tool, the CR7V steel was deep cryogenically treated at different dwelling times with multiple tempering. The hardness, impact toughness and wear resistance of the CR7V steel were examined, and the effects of deep cryogenic treatment on the microstructure of the CR7V steel were studied by means of optical microscope, scanning electron microscope and energy-dispersive spectroscopy. The results show that deep cryogenic treatment has little effect on the hardness of the tempered CR7V steel, but improves its impact toughness and wear resistance. The improvement in mechanical properties is a result of the combination of dissolution of large carbide particles, formation of small-sized and uniformly distributed carbide particles and fine tempered martensite structure. The cryogenic treatment is optimized as follows: vacuum gas quenching, deep cryogenic treatment at − 196 °C for 6 h and triple tempering at 560 °C for 2 h, which improves the wear resistance by 68% and the impact toughness by 58% compared to the conventional heat treatment.

Effects of Deep Cryogenic Treatment on Wear Resistance and Structure of GB 35CrMoV Steel

Wear resistance of metallic materials can be effectively improved by the deep cryogenic treatment. In this study, different deep cryogenic treatment conditions were considered, with different soaking durations between quenching and tempering. The main objective is investigating the effects of deep cryogenic treatment and exploring the relationship between the mechanical properties and the microstructure of GB 35CrMoV steel. Hardness and relative wear ratios of samples were evaluated by the Vickers-hardness test and the pin-on-disk wear test, respectively. Worn surface was characterized by a non-contact optical surface profiler. Microstructures were studied by scanning electron microscope (SEM) and X-ray diffraction (XRD). Significant improvements in hardness and wear resistance are observed for higher cryogenic soaking times; the root mean square deviation (RMS) parameter (Sq) was employed to evaluate the effect of deep cryogenic treatment on the worn surface roughness; the improvements were ascribed to the precipitated carbides. The mechanism can be interpreted not only as the promoted effect of deep cryogenic treatment in the decomposition kinetics of martensite, but also as the acceleration on the Ostwald ripening process.

Comprehensive Analysis on the Effect of Deep Cryogenic Treatment on The Mechanical Behaviour of Martensitic Valve steel

Comprehensive Analysis on the Effect of Deep Cryogenic Treatment on The Mechanical Behaviour of Martensitic Valve steel

Effect of Deep Cryogenic treatment on the mechanical properties of AISI D3 Tool steel

The research paper presents a study on deep cryogenic treatment and its effects on mechanical properties of AISI D3 grade high carbon steels. Commercially available AISI D3 steel was subjected to deep cryogenic treatment for soaking durations of 12 hours, 24 hours and 36 hours using a cryogenic refrigerator at ‒196°C and then followed by tempering for 2 hours at a constant temperature of 150°C. Thus prepared samples were tested as per ASTM standards to evaluate their mechanical properties such as microhardness, impact and tensile properties. Further, to understand the effect of deep cryogenic treatment, the fractured surfaces were subjected to scanning electron microscopic examinations. X-ray diffraction analysis and energy dispersive spectroscopic analysis were also conducted to investigate the changes in structure of the material after deep cryogenic treatment. Results indicate that 12 hours soaking time during cryogenic treatment will give optimum mechanical properties compared to 24 and 36 hours. Also, reduction in mechanical properties by 4-6% was observed for 24 and 36 hours cryogenic treated samples compared to 12 hours treated samples.

Effect of cryogenic treatment of tungsten carbide tools on cutting force and power consumption in CNC milling process

In this paper, the effect of Deep Cryogenic Treatment (DCT) soaking duration on tungsten carbide end mill cutters on cutting forces and power consumption during machining P20 mold steel in CNC milling machine is investigated and optimized the process parameters. The data collected for the study are based on Box–Behnken design of response surface methodology. Cutting forces and power consumption are considered as important performance measures which are functions of decision variables viz. cutting speed, feed, depth of cut, and end milling cutting tools subjected to different soaking duration. The percentage contribution is calculated based on ANOVA to identify most influencing parameter on cutting forces and power consumption. The study revealed that cryogenic soaking duration exhibits most significant effect on cutting forces and power consumption followed by cutting speed, feed, and depth of cut. Regression analysis is carried out to relate the process variables and performance measures. Finally, a non-dominated sorting Algorithm (NSGA-II) is proposed to optimize the process variable to obtain the desired optimal solutions. The results indicate DCT tool soaked for longer duration is minimizing the cutting forces and power consumption when compared to untreated tool.

Effect of deep cryogenic treatment on mechanical properties and microstructure of Sn3.0Ag0.5Cu solder

The effect of deep cryogenic treatment on the performance of steels and alloys has attracted wide attention in the past decades. Deep cryogenic treatment can improve the strength and hardness of steel at room temperature, provide microstructure stability and improve wear or fatigue resistance of material. In the current study, the effect of deep cryogenic treatment on the microstructure and mechanical properties of Sn3.0Ag0.5Cu solders are investigated. The influence to microstructure, tensile strength and ductility improvement are discussed. Experimental analysis shows that the tensile strength of Sn3.0Ag0.5Cu solder increases from 36.76 to 46.27 MPa after 600 h of deep cryogenic treatment at 77 K (− 196 °C), the observed strength-time relation is similar to the Taylor theory for the yield strength and dislocation density. Large particles presented in the fracture of Sn3.0Ag0.5Cu samples are caused by the high cooling rate as well as the concentration difference between the β-Sn and the eutectic system. The precipitated Ag3Sn particles exhibit relatively uniform distribution in deep cryogenic treated Sn-rich matrix, and the size of Ag3Sn particles becomes smaller with longer deep cryogenic treatment time. It is noted that deep cryogenic treatment can increase the internal stress and the dislocation density, higher dislocation density and good ductility lead to movement of the pre-existing dislocations and specific dislocation configurations. Microscopic experiments on solder joints were performed to investigate the microstructure change. The Intermetallic layers were measured which showed negligible change in thickness. A unified creep and plasticity constitutive model is proposed to simulate the stress–strain relationship under deep cryogenic treatment, the predictions show good agreement compared with experimental results.

Effect of deep cryogenic treatment on carbon segregation in Cr8Mo2SiV tool steel during tempering

Carbon segregation in Cr8Mo2SiV tool steel after common heat treatment (CHT) and deep cryogenic treatment (DCT) has been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) extraction replica and three-dimensional atom probe (3DAP) tests. The XRD results show that most of the retained austenite transformed to martensite after DCT. The TEM results confirm the transformation of blocky retained austenite to twin martensite during DCT. The 3DAP results reveal the segregation of carbon atoms and the maximum carbon fraction in carbon-rich regions increases after DCT. The peak carbon concentration in carbon-rich regions of SDC99 steel after CHT and DCT are 8 at. % and 15 at. %, respectively. The segregated carbon atoms grew into nuclei for nanoscale carbides precipitation on subsequent tempering.

Effect of cryogenically treated copper-tungsten electrode on tool wear rate during electro-discharge machining of Ti-5Al-2.5Sn alloy

Titanium, due to its excellent properties with high strength to weight ratio, is increasingly being used for various applications. Electric discharge machining (EDM), due to its unique features, is extensively used for machining of titanium and its alloys as it is difficult to machine titanium with conventional machining. EDM, however is most suited for electrically conductive materials and to make up for the poor thermo-electrical properties of Ti-5Al-2.5Sn titanium alloy, deep cryogenic treated (−184°C) copper-tungsten (Cu-W) tool has been used in this study for machining. This study reports the effect of deep cryogenic treatment (DCT) on tool wear rate during electric discharge machining of Ti-5Al-2.5Sn titanium alloy by varying various process parameters namely cryogenic treatment of electrode material, peak current, pulse-on & off time and flushing pressure. Fractional factorial experimental design was used for designing the experimental study and the results were statistically analyzed to obtain optimal combination of input process parameters for minimizing tool wear. Peak current was observed to be the most significant process parameter in relative comparison to other input parameters. The results show a significant reduction in tool wear rate in case of DCT Cu-W electrode when compared to untreated Cu-W electrode. Surface characteristics of select Cu-W electrode and workpiece samples were analyzed using scanning electron microscope (SEM), energy dispersive spectrograph (EDS) and X-ray diffraction (XRD). Various chemical compounds specifically titanium carbide (TiC) were seen on both the machined and the tool surface due to material transfer during machining.

Effect of Deep Cryogenic Treatment on the Microstructure and the Corrosion Resistance of AZ61 Magnesium Alloy Welded Joint

The effect of deep cryogenic treatment on the microstructure and corrosion resistance of an AZ61 magnesium alloy metal inert-gas (MIG) welded joint was investigated. The welded joints were deep-cryogenically treated using different parameters, and were analyzed by metallographic observations, X-ray diffraction, microhardness, and NaCl immersion test. The results show that the treatment changes the microstructure of the entire joint by causing grain refinement and increase in the β-phase. The crystal structure, chemical composition, and electrode potentials are different for the α and the β-phases. Therefore, any change in content, status, and distribution of the β phase has important implications on the corrosion resistance of the samples. With an increase in the holding time, the microhardness value of the whole joint increases, and the difference between the three regions of the joint decreases. The results of the NaCl immersion test show that there is an improvement in the corrosion resistance of the treated joints. Compared with the untreated samples, the corrosion potential of the samples treated by deep cryogenic treatment for 4 h at −180 °C is about 0.017 V higher, and the corrosion current density decreased by one order of magnitude (from about 2.769 × 10−5 A·cm−2 to 1.578 × l0−6 A·cm−2).

Use of Deep Cryogenic Treatment to Reduce Particle Contamination Induced Problem in Hard Disk Drive

In this study, the effect of deep cryogenic treatment on the generation of stainless steel particles in screw tightening process in hard disc drive assembly was investigated. During the cryogenic treatment, the specimens of both stainless steel screw and contacting tool (called as “bit”) material were quenched in a chamber containing liquid nitrogen at-196 oC with the soaking times of 33 hr. The specimens were then subjected to sliding wear tests under normal loading conditions. The experiments used for simulating dry sliding wear mechanisms were carried out by TriboGear machine. The machine consists of a stationary bit loaded against the plate containing screw. The screws used were made of martensitic 410 stainless steel and the bit was made of S2 tool steel. The experiments were carried out under both under single and multiple loading cycles under the normal load corresponding to the effective stresses higher and lower than the yield strength of screw material. The results showed that the deep cryogenic treatment led to more homogeneous distribution of fine size carbide particles in both martensitic 410 stainless steel and S2 tool steel. This lead to different failure mechanism of the stainless steel resulting in smaller and slender stainless steel particles generated. This was expected due to the effect of the change in the dimension of carbide, the stress distribution in the material and the crack propagation path.

Effect of Deep Cryogenic Treatment on Carbon Partition of Tempered High Carbon High Alloy Tool Steel SDC99

Effect of Deep Cryogenic Treatment on Carbon Partition of Tempered High Carbon High Alloy Tool Steel SDC99

Effect of Deep Cryogenic Treatment on Cyclic Fatigue of Endodontic Rotary Nickel Titanium Instruments.

Introduction:Cyclic fatigue is the common reason for breakage of rotary instruments. This study was conducted to evaluate the effect of cryogenic treatment (CT) in improving the resistance to cyclic fatigue of endodontic rotary instruments. Methods and Materials:In this in vitro study, 20 RaCe and 20 Mtwo files were randomly divided into two groups of negative control and CT. CT files were stored in liquid nitrogen at -196°C for 24 h, and then were gradually warmed to the room temperature. All files were used (at torques and speeds recommended by their manufacturers) in a simulated canal with a 45° curvature until breakage. The time to fail (TF) was recorded and used to calculate the number of cycle to fail (NCF). Groups were compared using independent-samples t-test. Results:Mean NCFs were 1248.2±68.1, 1281.6±78.6, 4126.0±179.2, and 4175.4±190.1 cycles, for the Mtwo-control, Mtwo-CT, RaCe-control, and RaCe-CT, respectively. The difference between the controls and their respective CT groups were not significant (P>0.3). The difference between the systems was significant. Conclusion:Deep CT did not improve resistance to cyclic fatigue of the evaluated rotary files.

Effect of Deep Cryogenic Treatment on Tribological Behaviour of D2 Tool Steel - An Experimental Investigation

This paper deals with the experimental study of friction and wear behavior of D2 tool steel. In the present work, the role of multiple tempering before and after deep cryogenic treatment on tribological behavior like friction and wear of D2 tool steel is focused. The heat treatments like hardening (1020°C) for one hour, tempering (210°C) for two hours and deep cryogenic treatment (-185°C) for 36 hours were done on D2 tool steel. Wear tests were performed using pin-on-disc wear tester to which normal load of 50 N and velocity of 1.5 m/s is applied. The hardness of specimens was measured by using Rockwell Hardness tester. The execution of deep cryogenic treatment increases the hardness; reduces the wear volume, wear rate and coefficient of friction of D2 tool steel. In this experimentation, various combinations of heat treatment are used. The optimum combination of heat treatment obtained was Hardening, Cryotreatment and Single Tempering (HCT). In HCT specimens there was a large reduction in the wear volume, wear rate (WR) and coefficient of friction; significant enhancement in hardness of the D2 tool steel.