Oil Quench Research Articles

FATIGUE BEHAVIOUR OF TEMPERED AND ISOTHERMAL HEAT TREATED AISI 5160 LEAF SPRING STEEL

The oil quench and temper technique have a lot of benefits for heavy duty spring manufacture since it may expose the best balance of toughness and ductility, as well as increase fatigue life. The current study looked at the fatigue behavior of tempered AISI 5160 leaf spring steel samples at tempering temperatures of 400, 450, 500, 550, and 600 °C, as well as isothermally heat- treated steel samples at 830 °C. All leaf spring steel samples that had undergone thermal tempering and isothermal heat treatment were then tested up to fracture utilizing rotational fatigue test equipment under the effect of various stress levels. All steel samples subjected to tempering heat treatments of 400°C to 600°C showed a decrease in hardness ratings. The Rockwell hardness ratings of the steel samples that treated to isothermal heat treatment increased significantly. Experimental fatigue testing revealed that the values of fatigue resistance for steel samples tempered at (400 and 450) °C temperatures dropped by a small amount. The fatigue resistance values for steel specimens tempered at 500 °C to 600 °C temperatures decreased more than the values for steel samples tempered at 500 to 600 °C temperatures. A fatigue resistance of steel samples that were treated to isothermal heat treatments, on the other hand, increased. Steel samples that were isothermally heat-treated at 830 °C and then chilled in a salt brine solution, on the other hand, showed an increase in fatigue resistance

Vegetable oil quench effect on impact toughness and hardness of 42CrMo4 steel

Quenching is the part of hardening treatment for hardenable steels to improve upon hardness influence properties. Several quenching mediums are available for this purpose, like, air, water, petroleum, oil, emulsions and blends, etc. Generally, 0.3–0.45 wt% carbon with a low quantity of alloying elements is the best composition for the steel to harden. 42CrMo4 steel is in the mentioned range of composition regarded as versatile steel, application ranging from fasteners to dies. This work aims to determine the influence of vegetable oil quenchants such as Pinnay oil, Karanja oil and their blend on impact toughness and hardness of 42CrMo4 steel since mineral oil quenchants are producing negative impacts on the environment because of their non-biodegradability and toxicity. Vegetable oil quench media are a good alternative to non-renewable mineral oil quench due to their biodegradable and non-toxic nature.

Assessment of Cooling Performance of Neem Oil for Distortion Control in Heat Treatment of Steel

Growing concerns over the hazardous impact of mineral oil-based industrial quench media on human health and the environment have forced researchers to seek renewable and non-hazardous alternatives. Non-edible vegetable oil-based quench media are perceived to be a potential replacement for mineral-based industrial quench media. The present work focuses on assessing the cooling performance of neem oil as compared to commercial hot oil quench media. Inconel and steel probes were used to characterize the cooling performance of these quench media maintained at bath temperatures 100 °C, 150 °C and 200 °C. The heat extraction rates and uniformity of heat extraction in Inconel probes quenched in neem oil were observed to be substantially higher at all bath temperatures. The hardness of AISI 52100 steel probe quenched in neem oil at all bath temperatures was observed to be higher. The pearlitic microstructure was observed in the steel probe quenched in hot oil maintained at 200 °C bath temperature. In contrast to this, a mixture of bainite, martensite and carbide was observed in case of steel probes quenched in neem oil maintained at 200 °C. Oxidation experiments revealed that neem oil is susceptible to an increase in viscosity due to oxidation. An increase in the viscosity by about 15% was observed in the case of neem oil as compared to only 4% increase in viscosity of hot oil. However, after an initial increase, the viscosity of neem oil stabilized and further no significant change in viscosity due to oxidation were observed. Oxidation had no significant effect on the cooling performance hot neem oil quench medium, and thus, it can be considered as an effective replacement for hot oil.

A Comparative Study on Cooling Performance of Hot Oil and Molten Salt Quench Media for Industrial Heat Treatment

The present work presents a comprehensive comparative study on the cooling performance of hot oil and molten 54%KNO3-7%NaNO3-39%NaNO2 eutectic mixture quench media. The study was conducted using a cylindrical Inconel probe of 12.5 mm diameter and 60 mm length. Cooling curves at different locations in the probe were acquired and were subsequently used to calculate spatially dependent transient heat flux at the metal/quenchant interface. The heat extraction mechanism in hot oil and NaNO2 eutectic mixture was found to be different. Heat transfer occurred in two stages, namely boiling stage and convective cooling stage during quenching in molten NaNO2 eutectic mixture. In the case of hot oil, apart from these two stages, third stage of cooling, namely vapor blanket stage, was observed. A detailed study was conducted to compare the magnitude and uniformity of heat extraction during each stage of quenching. Molten salt offered a higher cooling rate and more spatial uniform cooling as compared to that obtained in hot oil quench medium. The non-uniformity in surface temperature during boiling stage in Inconel probe was ten times lower in molten salt medium as compared to that observed in the hot oil medium. However, the non-uniformity in surface temperature during convective cooling stage in both the media were comparable. Based on the distribution of characteristic cooling time (t85) calculated in quenched Inconel probe, higher and uniform hardness distribution is predicted in steel parts quenched in molten NaNO2 eutectic mixture media as compared to that in hot oil.

MICRO-CRYSTAL STRUCTURE OF 57Fe15Cr25Ni0.32Mn0.96Si AUSTENITE STEEL AFTER 850°C-5H TEMPERATURE-QUENCHING TREATMENTS FOR HIGH TEMPERATURE MATERIAL APPLICATIONS

MICRO-CRYSTAL STRUCTURE OF 57Fe15Cr25Ni0.32Mn0.96Si AUSTENITE STEEL AFTER 850°C-5H TEMPERATURE-QUENCHING TREATMENTS FOR HIGH TEMPERATURE MATERIAL APPLICATIONS. A serial austenite stainless steel, namely A2-type, has been synthesized by using casting technique at temperature more than 1250 °C in the induction furnace that used an electromagnetic inductive-thermal system. The steel is dedicated for structural component material in multi-purpose applications such as in high-temperature operating environments. So, the material must be resistant to mechanical loads, high temperature, corrosion and irradiation. In order to increase the strength of materials, temperature-quenching treatments are required in some cooling media. Mineral element was extracted from crude ores of Indonesian mines and commercial scrap materials, i.e: ferro scrap, ferro chrome, nickel, manganese, and ferro silicon; all of them in granular shape were prepared to alloy the steel. Titanium was not added to this austenite low carbon steel. The OES-chemical composition in %wt of the materials is 57%Fe, 15%Cr, 25%Ni, 0.34%C and less than 0.1% of impurities that comprised of: titanium, phosphor, copper, niobium and sulphur elements in the steel. X-ray diffraction pattern shows that ascast material had an fcc crystal structure with lattice parameter of 3.632 Å. Meanwhile, two of samples, i.e: annealing and oil quench, have strictly similar lattice parameter to that of air (normalizing) quench (3.580 Å). On the other hand, the lattice parameter of water quenched samples has a slightly lower lattice parameter than the ascast lattice , i.e. 3.587 Å. The peak shift of (111) and (200) -plane in the diffraction profile, is very significant, approximately 0.63 degrees between ascast sample and the last two samples. Ascast microstructure reveals that the austenite phase grains look large and describe an undeformed structure, with an average grain size of about 6 mm, while the annealed sample was larger. Air- and oil- quenched sample microstructures showed a fine grain which was very different to water quenched sample microstructure that showed a coarse grain. The viscousity (h) of the quenching medium had an important role in the formation of grain boundary, because the rate of decreasing temperature was heavily influenced by the diffusion of heat from the high to low temperature spaces.

Effect of Section Thickness on Heat Transfer during Quenching in Vegetable Oils

In the present work, mineral, sunflower, karanja, and neem oil were used as quench media. 304 stainless steel probes with diameters of 25 mm and 50 mm were quenched in these oils to assess the effect of section diameter on heat transfer during quenching. Cooling curve analysis was carried out by instrumenting the probes at various locations with thermocouples. The heat extraction ability of oil quench media was quantified using an inverse heat conduction method. Thermal data and the predicted hardness values showed the suitability of nonedible vegetable oils as potential quenchants to heat treat steels. The predicted hardness was higher during quenching in karanja oil compared to other oil media.

Deformation characteristics of the intermetallic alloy 60NiTi

The deformation behavior of a Ni-rich Ni55Ti45 (at.%) alloy, commonly known as 60NiTi (as designated in wt.%), was analyzed using neutron and synchrotron x-ray diffraction during in situ isothermal tension and compression loading, and pre and post-test electron microscopy. The alloy was shown to exhibit remarkable strength and high hardness resulting from a high density of fine Ni4Ti3 precipitates (size ∼67 nm), which were uniformly dispersed throughout the matrix after a solution treatment and oil quench. The precipitate volume fraction was 55 ± 3%, determined from both the neutron Rietveld refinement and conventional x-ray measurements. Non-linear stress-strain behavior was observed in tension (but not in compression) and was attributed to reversible stress-induced martensite (SIM) that forms to accommodate the stress as revealed by neutron diffraction measurements. The tensile and compressive neutron data also showed peak broadening and residual lattice strains. Transmission and scanning electron microscopy revealed stress-induced coarsening of Ni4Ti3 precipitates in both tension and compression tested samples, but precipitation and growth of the stable Ni3Ti phase was observed only after tensile testing. Finally, the potential ramifications of these microstructural changes are discussed.

METALLURGICAL AND CORROSION CHARACTERIZATION OF POST WELD HEAT TREATED DUPLEX STAINLESS STEEL (UNS S31803) JOINTS BY FRICTION WELDING PROCESS

The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080[Formula: see text]C, 1150[Formula: see text]C and 1200[Formula: see text]C with 15[Formula: see text]min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080[Formula: see text]C followed by water quench and at 1150[Formula: see text]C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase presence and absence of precipitates were conformed through TEM which follow Kurdjumov–Sachs relationship. PREN of ferrite was decreasing with increase in temperature and that of austenite increased. The equilibrium temperature for water quenching was around 1100[Formula: see text]C and that for oil quenching was around 1140[Formula: see text]C. The pit depths were found to be in the range of 100[Formula: see text]nm and width of 1.5–2[Formula: see text][Formula: see text]m.

A Raman spectroscopy investigation into the influence of thermal treatments on the residual stress of polycrystalline diamond

A systematic study of the residual stress distribution in number of polycrystalline diamond grades was performed using Raman spectroscopy. The analysis focuses on evaluating the stress state in the specimen both before and after oil quench treatment, with a particular emphasis on the role of the second phase material. Prior to heat treatment, measurements along the surface of the specimen indicate an average residual stress in excess of 1.5GPa for all grades examined. For specimens subjected to oil quenching at 600°C an increase in the presence of tensile stress was recorded. The removal of the cobalt second phase from the surface of the microstructure had the effect of limiting this increase of tensile stresses on the specimen surface. Numerical modelling of the quench experiment was performed for polycrystalline diamond using the finite volume method (FV). The increase in residual stress, observed experientially after oil quenching was reproduced numerically, validating the experimental approach for approximating the stress distribution on the surface of the specimens.

Characterization of Gamma Prime (γ′) Precipitates in a Polycrystalline Nickel-Base Superalloy Using Small-Angle Neutron Scattering

Small angle neutron scattering (SANS) has been used to evaluate the temporal evolution of the secondary and tertiary γ′ precipitates in the nickel-base superalloy, RR1000, in situ during an aging heat treatment at 1033 K (760 °C) following a supersolvus heat treatment and oil quench. The bimodal distribution of secondary and tertiary γ′ was analyzed using a specially developed polydispersive model capable of evaluating the scattering curves to obtain precipitate size distributions (PSDs) and volume fractions as a function of time. The model was designed to be suitable for high volume fractions of γ′ and takes into account the scattering interaction between precipitates. The results show an increase in the volume fraction and the mean particle size of both the secondary γ′ and tertiary γ′ during aging. The initial and final precipitate distributions have been characterized using transmission electron microscopy (TEM) and show satisfactory correlation with the SANS data across the scattering vector range.

The effect of serrated yielding on the determination of r-values in aluminium alloys and yield locus calibration

This study investigates the effect serrated yielding (Portevin-Le Châtelier effect) has on the determination of the plastic strain ratio ( r-value) for the 2024 aluminium alloy. The aluminium alloy specimens were initially in the fully annealed O-condition. The specimens experienced a softening mechanism through a solution heat treatment (SHT) process, followed by an oil quench. The specimens were permitted to recover for periods ranging between 0.5 and 12 h by room temperature (RT) natural ageing before undergoing a uniaxial tensile test along the longitudinal axis to determine the r-value as a function of natural ageing time. The current study reveals the irregular variation in the transverse strain affects the gradient of the longitudinal–transverse strain plot and consequently the r-value. It is demonstrated that the serrated yielding directly influences the Hill 1948 yield locus when calibrated using two r-values and one yield strength for the 2024 aluminium alloy. Serrated yielding results in an underestimation of the plane stress (rolling) of 0.5 ≤ plane stress rolling (MPa) ≤ 5.6, plane stress (transverse) of 1.0 ≤ plane stress transverse (MPa) ≤ 9.2, and biaxial stress of 1.4 ≤ biaxial stress (MPa) ≤ 7.4. It is also shown that serrated yielding occurs after a critical strain of 0.07 ≤ plastic strain ≤ 0.13 and is reduced by natural age hardening.

New Developments in Improving the Capability of Oil Quench Systems in Sealed Quench Furnaces

Oil quench systems of batch furnaces in the past had little flexibility with respect to varying the quench intensity. Today's requests of adapting the quenching intensity of oil quench systems to the needs of different components with respect to hardening capability and minimising of distortion led to the development of a new oil quench system with a largely increased agitation power and adjustable oil flow speeds. This increases the utilisation of oil quench systems and makes the hardening of lower alloyed materials and thicker sections possible as demonstrated on some industrial examples. A special quench sensor measuring the heat transfer coefficient in the convection phase of the quenching is helpful in setting-up complex quenching cycles. It is also useful for quench cycle documentation, quench tank mapping and quench tank bench marking.

Effect of cooling rate on the high strain rate properties of boron steel

In this work, the effect of cooling rate on the high strain rate behavior of hardened boron steel was investigated. A furnace was used to austenize boron sheet metal blanks which were then quenched in various media. The four measured cooling rates during the solid state transformation were: 25 (compressed air quench), 45 (compressed air quench), 250 (oil quench) and 2200 °C/s (water quench). Micro-hardness measurements and optical microscopy verified the expected as-quenched microstructure for the various cooling rates. Miniature dog-bone specimens were machined from the quenched blanks and tested in tension at a quasi-static rate, 0.003 s −1 (Instron) and a high rate, 960 s −1 (split Hopkinson tensile bar). The resulting stress vs. strain curves showed that the UTS increased from 1270 MPa to 1430 MPa as strain rate increased for the specimens cooled at 25 °C/s, while the UTS increased from 1615 MPa to 1635 MPa for the specimens cooled at 2200 °C/s. The high rate tests showed increased ductility for the 25, 45 and 250 °C/s specimens, while the specimens cooled at 2200 °C/s showed a slight decrease. The Hollomon hardening curve was fit to the true stress vs. true strain curves and showed that the mechanical response of the high rate tests exhibited a greater rate of hardening prior to fracture than the quasi-static tests. The hardening rate also increased for the specimens quenched at higher cooling rates. Optical micrographs of the fractured specimens showed that the failure mechanism transformed from a ductile-shear mode at the lower cooling rates to a shear mode at the high cooling rates.

Ferrous arrowheads and their oil quench hardening: Some early Indian evidence

A wide variety of ferrous arrowheads were in use in ancient India. Several typical chemical analyses of arrowheads found from archaeological excavation carried out at Kaushambi are reported in this paper. The average carbon content of these arrowheads varied from as low as 0.1 wt.% to approximately 0.9 wt.%. Literary evidence for oil quench hardening of ferrous arrowheads, as reported in famous Sanskrit epics—the Rāmāyana and the Mahābhārata—have been discussed in this paper. This type of quench hardening was intentionally adopted as it helped in preventing distortion and formation of quench cracks in arrowheads. The oil quench-hardened arrowheads were rubbed on stones to sharpen them, which also brought about tempering of martensite due to frictional heat.

Substitution of quenching oils with high risk of fire by water-based quenchants – without flames and fumes∗

Abstract The practice of using large open tanks filled with oil for heat treatment can be consigned to history thanks to the development of new technology. Today FEROQUENCH, a water-based quenchant, is widely used to replace open oil quench tanks and this trend is accelerating. Comprehensive practical experience is now available to prove that a water-based polymer quenchant with oil-like quenching properties is capable of providing excellent performance over many years of service. In many cases the conversion of an oil-quenching system is straightforward, although quenchants with a high waterconcentration always require good agitation due to the lower boiling temperature of these fluids compared with oil. The quenching properties of water-based polymer quenchants are much more influenced by the bath-temperature than those of oils. Therefore the temperature has to be controlled to reach constant and homogenous cooling properties. The paper details properties of water-based quenchants together with application parameters and examples of working systems.

Comparative study of heat transfer and wetting behaviour of conventional and bioquenchants for industrial heat treatment

An investigation was conducted to study the suitability of vegetable oils as bioquenchants for industrial heat treatment. The study involved the assessment of the severity of quenching and wetting behaviour of conventional and vegetable oil quench media. Quench severities of sunflower, coconut and palm oils were found to be greater than mineral oil. The quench severity of aqueous media is greater than oil media although their wettability is poor as indicated by their higher contact angles. A dimensionless contact angle parameter defined in this work is found to be a better parameter to compare the wetting behaviour with heat transfer.

Effect of Heat Treatment on Microstructure and Mechanical Property of 45XD and 47XD TiAl Alloys

The effect of heat treatment on microstructure and property of Ti-45 and 47Al-2Nb-2Mn+0.8%vol.%TiB2 alloys (45XD and 47XD) has been studied. Annealing and subsequent oil quench produced fine-grained fully lamellar structure (FGFL) in both alloys. For microstructural stabilization, the FGFL structures were subjected to different aging treatments. Microstructural examination showed that degradation of the FGFL structure, such as coarsening of γ lamellae, recrystallization of γ grains and break-up of a2 lamellae, presented to varying degrees after different aging treatments. Hardness values in the aged alloys decreased due to the degradation. The creep resistances were improved in the aged alloys though the degradation occurred, indicating that the aging treatments stabilized the FGFL structures effectively. The differences in the changes of properties caused by different aging treatments and compositions were compared in combination with the microstructural variants.

Plasma post oxidation of nitrocarburized hot work steel samples

Pulse plasma oxidation of untreated, salt bath nitrocarburized and plasma nitrided/nitrocarburized samples made of hot work steel grade H11 was investigated. A continuous multi-step plasma processing was performed consisting of a half an hour plasma nitriding at 520 °C followed by 3.5 h nitrocarburizing at the same temperature and by a subsequent post-oxidation in a low current density H 2O glow discharge during 45 min at 450 °C. The salt bath nitrocarburizing was carried out at a temperature of 580 °C for 210 min and was followed by the oil quench. In order to compare the oxide layer growth on the base material and on the ε-Fe 2(N,C) 1− x layer the salt bath treated sample was half cut and plasma post-oxidized in a 80% H 2O−20% H 2 glow discharge for 45 min at the temperature of 480 °C. In plasma processing pulse power supply was used with 57 μs pulse duration and 3 μs pulse pause. The surface structures were analyzed by optical microscopy, SEM and XRD, while Vickers microhardness test was used for measuring the surface microhardness and microhardness distribution over the sample cross sections. On the nitrocarburized surfaces XRD analyses revealed the existence of a superficial magnetite oxide layer and the presence of a ε phase and a small amount of γ′ phase, while a hematite Fe 2O 3 layer was formed on untreated sample surface.

Chute Quench Design Recommendations

It has been shown that the quenching mechanism of aqueous polymer quenchants, particularly PAG quenchants, facilitate uniform heat transfer. The quench system is properly designed to provide adequate heat transfer and agitation. It was shown through previously conducted work by Illgner that even parts with relatively small cross-section sizes are not through-quenched in the chute zone. Polymer quenchants can be used in continuous chute-quench system if adequate temperature control and agitation are present in the chute zone. Recommended design guidelines and illustrative examples have been provided. Although the focus of this work was on polymer quenchants, the same guidelines can be applied to oil quench system for improved performance.

The effects of heat treatment variables on the microstructure and properties of ultra-high strength steels differing in titanium content

The influences of different austenitizing and tempering temperatures on the microstructure and properties of three experimental ultra-high strength steels (UHS) have been investigated. The steels had different Ti content and were subjected to austenitizing treatment at 900, 1000, 1100 and 1200°C followed by oil quench and tempering at 200, 300, 450 and 600 °C. It has been found that the high temperature (1100 and 1200 °C) austenitizing treatments, alter both microstructure and properties, and depending on the subsequent tempering temperature, may have a beneficial or detrimental influence upon the mechanical properties. Addition of up to 0.011 wt% Ti to the steel composition improves hardness, toughness and tensile strength. This improvement in mechanical properties is obtainable with any subsequent heat treatment. For higher Ti content (0.089 wt%), although some further improvement in hardness and tensile strength was obtained, significant degradation in toughness was achieved, particularly when the steel was subjected to high temperature austenitizing and tempering treatment.