Quench Hardening Research Articles

Pre-hardening water quenching effect on the wear resistance of TiCN coated 4140 steels

In this comprehensive study, we investigated the mechanical and wear characteristics of AISI 4140 steel specimens subjected to quench hardening and coated with Titanium Carbo Nitride (TiCN) using the Physical Vapor Deposition (PVD) technique. Our analysis encompassed microstructure characterization, cross-sectional examination of the coating layer, phase analysis, microhardness evaluation, and wear behavior assessment, aiming to discern the combined impact of TiCN coating and pre-hardening treatment. The surface imaging and characterization of the coating layer were conducted employing Energy Dispersive Spectroscopy (EDS) assisted Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Hardness measurements were performed utilizing a microhardness testing apparatus. Furthermore, wear assessments were executed employing a ball-on-disc tribometer, employing two distinct loads of 20 and 40 N. Results revealed that the pre-hardening process led to a remarkable coating surface hardness of 2473 HV, surpassing the 2230 HV recorded in AISI 4140 steel without pre-hardening. Pre-hardening notably improved coating thickness and hardness, and substantially reduced wear rates, especially when combined with TiCN coating. In conclusion, the combined approach of pre-hardening and TiCN coating emerges as a highly effective strategy for enhancing the mechanical and wear properties of this steel alloy.

High-speed milling of hardened steel under minimal quantity lubrication with liquid nitrogen

Minimal quantity lubrication (MQL) can effectively reduce tool wear and improve surface quality in the high-speed milling of hardened steel, but MQL still suffers from poor cooling effect and oil-film failure at high cutting temperature. Compared with MQL, the cryogenic liquid nitrogen (LN2) or LN2 + MQL method with a highly strong cooling ability can further improve the processing conditions of the high-speed milling of hardened steel. However, the knowledge about the characteristics and mechanisms of the high-speed milling of hardened steel under the cryogenic LN2 and LN2 + MQL cooling is scarce. Thus, high-speed milling of hardened steel under cryogenic LN2 and LN2 + MQL cooling was studied in this paper. The machining characteristics were analyzed, and the machining mechanisms of cooling lubrication, tool wear, and surface deterioration layer formation were discussed. The experimental results show that the tool life of LN2 + MQL is remarkably longer than that of MQL, and high surface quality can be maintained at a long cutting distance. In the high-speed milling of hardened steel under the LN2 and LN2 + MQL modes, adhesion has little effect on tool wear, abrasion and chipping/flaking are the main tool wear mechanisms, and chipping/flaking is the main mechanism of tool breakage. MQL reduces the cutting interface friction using oil-film boundary lubrication, LN2 quickly removes the cutting interface heat using a strong cooling and heat transferability, and LN2 + MQL combines the advantages of both cooling and lubrication. Compared with MQL, the surface hardness of the plastic deformation layer of the LN2 and LN2 + MQL modes is considerably increased, whereas the thickness is smaller, and the strong low-temperature cooling is the main reason for this difference. The increase in tool wear will promote the cutting temperature and material slip deformation, increase the depth of high stress and strain zone and eventually increase the thickness of the plastic deformation surface layer in the LN2 and LN2 + MQL modes. In the two modes of LN2 and LN2 + MQL, there are no oxidation, nitridation, secondary quench hardening, and phase transformation in the surface layer. Severe dislocation strengthening caused by severe plastic deformation of the surface layer is the main hardening mechanism of the workpiece surface layer.

Quench hardening effect of gray iron brake discs on particulate matter emission

In this study, particulate matter produced during the braking of motor vehicles was investigated. In particular, this study focused on the effect of quench hardening of gray iron discs on brake emissions. The disc hardening effect was evaluated with commercial low-steel and non-steel brake pads using a 1/5 scale inertial brake dynamometer equipped with a particle counter. The results indicate that the disc hardening effect was significantly affected by the type of friction material due to different wear mechanisms. The low-steel brake pads produced more brake emissions when using the quench-hardened disc due to the increased aggressiveness of the hardened disc against the brake pad. In contrast, the hardened disc substantially reduced particulate matter emission when using the non-steel brake pads because the pad's surface became more wear-resistant due to the smaller amount of iron transferred from the hardened disc compared to conventional gray iron discs. These results suggest that the iron transfer from the disc to the pad's surface plays a crucial role in brake emissions.

Experimental investigation of heat transfer characteristics of polyethylene glycol (PEG) based quench media for industrial heat treatment

Aqueous polymer quenchants are now increasingly used in the quench hardening of steels. The inverse solubility property of polymer media leads to polymer film encapsulation of the quenched component, followed by an instantaneous rupture of the polymer film. The film boiling stage is absent, thus improving heat transfer uniformity. In the present investigation, the effect of molecular weight of Polyethylene glycol (PEG) on heat transfer characteristics of PEG/water quenchants with concentrations of 5, 10, and 20 vol% was studied. The cooling curve analysis is performed to assess the cooling characteristics. Spatially dependent surface heat flux transients are estimated using the inverse heat conduction method. The rewetting kinematics is analyzed by videography and acoustic analysis of polymer film rupture during quenching. The results indicated that an increase in the molecular weight of PEG from 200 to 6000 changed the rewetting kinematics from a local wetting front movement to an instantaneous rupture of the polymer film. The change in the rewetting kinematics is reflected in the surface heat flux, indicating an increased uniformity of heat transfer. The film rupture acoustics showed that the polymer film's instantaneous breakup had a higher sound intensity than the one showing wetting front motion.

A "Nonsolvent Quenching" Strategy for 3D Printing of Polysaccharide Scaffolds with Immunoregulatory Accuracy.

3D printing enables the customized design of implant structures for accurately regulating host responses. However, polysaccharides, as a major biomaterial category with versatile immune activities, are typically "non-printable" due to the collapse of their filaments extruded during printing. This challenge renders their potential as immunomodulatory scaffolds underexploited. Here, inspired by the quench hardening in metal processing, a nonsolvent quenching (NSQ) strategy is innovatively designed for the 3D printing of polysaccharides. Through rapid solvent exchanging, NSQ instantly induces surface hardening to strengthen the polysaccharide filaments upon extrusion, requiring neither chemical modification nor physical blending that alters the material properties. Tested with five polysaccharides with varying physicochemical properties, NSQ prints predesigned structures at organ-relevant scales and a long shelf-life over 3 months. Glucomannan scaffolds, fabricated via NSQ with different grid spacings (1.5 and 2.5cm), induce distinct host responses upon murine subcutaneous implantation-from specific carbohydrate receptor activation to differential immunocytes accumulation and tissue matrix remodeling-as mechanistically validated in wild-type and Tlr2-/- knockout mice. Overall, NSQ as a facile and generic strategy is demonstrated to fabricate polysaccharide scaffolds with improved shape fidelity, thereby potentially unmasking their accurate immunomodulatory activities for future biomaterials design.

Residual Stress and Distortion during Quench Hardening of Steels: A Review

Residual Stress and Distortion during Quench Hardening of Steels: A Review

Assessment of Heat Transfer Characteristics of Transesterified Waste Sunflower Cooking Oil Blends for Quench Hardening

Assessment of Heat Transfer Characteristics of Transesterified Waste Sunflower Cooking Oil Blends for Quench Hardening

Tailoring microstructure of wire arc additively manufactured C–Mn–Si steel with post process heat treatment

Wire + arc additive manufacturing (WAAM), a promising technology to produce complex parts, was used to produce steel components with a custom-designed cored-metal wire. The chosen chemical composition of the cored wire is known to produced advance high-strength steel. The as-printed microstructure consists of martensite, retained austenite, and different morphological phases of ferrite, including quasi-polygonal, acicular, and Widmanstatten. Nanoindentation shows the highest hardness value for martensite, followed by acicular ferrite and then quasi-polygonal ferrite. However, a considerable spatial microstructural heterogeneity was observed in as-printed samples due to thermal cycling and chemical segregation. A higher fraction of harder martensite phase was observed at the bottom of the printed coupon, and the phase fraction of martensite decreased due to heat accumulation along the deposition height. Microstructural heterogeneity is reflected in the inhomogeneous distribution of nanohardness. Tempering of the printed sample results in carbide precipitation in martensite phases, leading to a decrease in the martensite hardness, but the heterogeneity is conserved. Both quench hardening and quenching and partitioning (Q&P) treatment were found to homogenize the microstructures. The quench-hardened samples' microstructure was comprised of lath martensite, while the Q&P treatment led to formation of tempered martensite and retained austenite.

Research into in-service deterioration of ball-rolling rolls

This work features research findings on causes of deterioration occurring in ball-rolling rolls. The causes of such deterioration may originate not only in the excessive loads application and the use of bottleneck operating parameters but also in the specific process being implemented and the equipment used to heat-treat the rolling rolls. The deterioration occurring in roll flanges having a relatively small thickness was used to demonstrate that, to prevent the deterioration of ball-rolling roll flanges, the mill design must accommodate the minimum allowable flange widths obtained as a function of maximum allowable loads and the roll pass calculations. The next example of roll deterioration involved the use of a gas furnace to implement the heating stage of the quench hardening process for rolls made of 35KhGSA steel, which, as a result, developed roll deterioration. The use of rolls of the same steel grade, which were heat-treated in an arc furnace prior to being quenched, has been shown to deliver long-lasting positive results evidenced by many years of their operation. Rolls made of 5KhNM steel have also been shown to respond well to the heat treatment preceding the quenching process, but this time, the treatment was implemented in a gas furnace.

Nanoindentation-Based Micro-Mechanical and Electrochemical Properties of Quench-Hardened, Tempered Low-Carbon Steel

The nanoindentation technique is widely used to measure the micro-scale mechanical properties of various materials. Herein, the nanoindentation-based micro-mechanical and electrochemical properties of low-carbon steel were investigated after quench hardening and tempering processes. The steel was produced on a laboratory scale and subjected to quench hardening separately in two different media-water and brine (10 wt% NaCl)-and subsequent moderate temperature tempering. Microstructure analysis revealed that the lath martensite phase formed after all heat treatments, having different carbon percentages ranging from 0.26% to 0.58%. A ferrite phase was also observed in the microstructure in three different morphologies, i.e., allotriomorphic ferrite, idiomorphic ferrite, and Widmanstätten ferrite. Nanoindentation analysis showed that the brine quench hardening process provided a maximum twofold improvement in indentation hardness and a 51% improvement in stiffness with a 30% reduction in reduced elastic modulus compared with as-received steel. Electrochemical performance was also evaluated in a 1% HNO3 solution. The water quench-hardened and tempered sample exhibited the highest corrosion resistance, whereas the brine quench-hardened sample exhibited the lowest corrosion resistance among all heat-treated samples.

DEUTSCHE EDELSTAHLWERKE CRYODUR 2067

Abstract Deutsche Edelstahlwerke Cryodur 2067 is a high-carbon, 1.5% chromium, alloy cold-work tool steel. In view of its higher hardenability than that of the non-alloy, water-hardening, cold work tool steels, this steel can be oil quenched, a factor that minimizes dimensional changes during quench hardening. Cryodur 2067 is suitable for short run tooling in applications requiring high surface hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, and machining. Filing Code: TS-786. Producer or source: Deutsche Edelstahlwerke Specialty Steel.

Wear resistance of strengthened layers with nanocrystalline structure in friction with boundary lubrication

Friction treatment refers to surface strengthening (hardening) methods using highly concentrated energy sources. The source of thermal energy occurs in the contact area of the tool-part due to high-speed friction (60–90 m/s) of the tool on the treated surface. The heating rate of the metal surface layer is 105–106 K/s. After moving the energy source from the contact zone, high-speed cooling of the surface layer of the metal takes place. The cooling rate is 104–5∙105 K/s. Under the action of high-speed heating and cooling of the contact area of the tool-part in the surface layers, a strengthened (hardened) nanocrystalline (white) layer is formed. The formed nanocrystalline surface layer has other physical, mechanical, chemical properties in comparison with the base metal of the part. Studies have shown that in the process of friction treatment of working surfaces of parts made of Steel 40NiCr6 (quench hardening and low-temperature tempering) a strengthened layer with a thickness of 250–320 μm with a hardness of 7.6–9.2 GPa is formed. The grain size of the surface strengthened layer was 20–40 nm near the treated surface. The formation of the strengthened layer is influenced by the shape of the working surface of the tool. Thus, a strengthened layer of greater thickness and hardness is obtained when machining with a tool with transverse grooves on the working part than with a tool with a smooth working part. Experimental studies in friction with maximum lubrication of pair “Steel 40NiCr6 and Grey Cast Iron GG20” showed that the strengthened nanocrystalline layer significantly increases the performance during sliding friction. Only samples made of steel were strengthened, counter-samples made of gray cast iron were not strengthened. The wear intensity of strengthened pair is 2.2–3.1 times less compared to unstrengthened pair. During the friction of the strengthened pair, the coefficient of friction and the temperature in the sliding zone also decrease. The best results were obtained when studying the friction pair in which the samples were strengthened with a tool with transverse grooves on its working part.

Pengaruh Perlakuan Panas terhadap Kekerasan Baja Karbon Tinggi Bohler K460

Steel is the kind of metal that most widely used in various fields of engineering, particularly for industrial purposes, like building construction, aircraft construction, the manufacture of tooling equipment, and others. The number of usage on the kind metal is not separated from the properties owned, such as: easy to set up, but has strong and tough properties are easily processed by machining. The use of high-carbon steel is mainly used for making springs, and die cutting tools and forming tools. Carbon steel with high strength and hardness has a better after heat treatment. Heat treatment that frequently applied was the process of hardening (quench hardening) and tempering. This research would conducted in the laboratory experiments and is planned to last for 8 (eight) months. The material to be used was of high carbon steel. High carbon steel(Bohler K460) is heated to a temperature variation of 850oC, and 900oC with their respective holding time that used for 24 minutes, then quenched in the salt water. The research data was obtained through the process of tensile testing, hardness testing and metallographic structure. This research aims to determine the properties of hardness determine the effect of heat treatment parameters, namely temperature, holding time and cooling medium to high carbon steels violence at the time of quenching and to analyze the mechanical properties of high carbon steels as a result of variations in heat treatment. The results indicate that the variation of heat treatment parameters (i.e. temperature, holding time, and cooling media) against the carbon steel of high hardness makes a difference significant influence on the hardness after quenching process. With a temperature difference, 8500C and 9000C temperature and holding time for 24 minutes and then do the quenching process results in changes in the value of the highest hardness of 64.8 HRC was obtained after quenching process at a temperature of 900oC.

Transient contact behavior of aqueous polymer solution droplets with transparent hot solid

In the metal forming industry, quench hardening is commonly used to strengthen steel products by rapidly cooling hot materials. One of the typical coolants used in the quench hardening process is an aqueous polymer solution. During the hardening process, several phenomena occur simultaneously, namely, coolant boiling, separation of the polymer from the aqueous solution, and formation of a polymer-enriched layer on the solid surface. The hydrodynamics and heat transfer characteristics of the coolant during the cooling process are complex in nature and remain unclear. The main objective of this study is to develop an experimental understanding of the collision and contact behavior of aqueous polymer solution droplets with a hot substrate. This research will serve as a fundamental reference work for the process of quench hardening using spray cooling. To fulfill this objective, a three-directional flash photography technique was developed. A transparent sapphire prism was used to observe the transient contact behavior of droplets with a hot solid, whose temperature was varied from 300 to 600 °C. A solution of 10 wt% polyoxyethylene-polyoxypropylene glycol with an average molecular weight of approximately 20,000 was used as the test liquid. At a substrate temperature of 300 °C, jellylike polymer residue remained on the substrate. At 400 and 500 °C, a wet area appeared temporarily on the solid substrate soon after the droplet collision, but this area eventually disappeared because of the thermal decomposition of the polymer. At 600 °C, no wet area was seen. The lifetime of the temporary wet area decreased with an increase in the temperature of the solid but was almost independent of the impact inertia of droplets. In addition, in the case of the polymer solution droplet, the upper limit of the surface temperature for forming the wet area was around 580 °C, which was considerably higher than that in the case of a water droplet.

Study of PSHG and its integrated hardening model of hardening layer

Pre-stressed hardening grinding (PSHG) combines with the advantage of grinding hardening and pre-stressed grinding. Ideal residual stress can be obtained along with the hardening effect on the surface of workpiece. In order to study its unique hardening characteristic, the paper divided the comprehensive hardening effect of PSHG into quench-hardening effect and work-hardening effect. Combining with the PSHG experiment, the quench hardening rules and mechanism were studied. The stabilization of parent phase and dislocation-induced nucleation due to applying pre-stress has comprehensive effect on the martensite transformation. So, the quench-hardening effect increases first and then decreases with the increasing of pre-stress. From the perspective of energy transformation, a model of quench hardening was established which can describe its relation with pre-stress in PSHG. The mechanism of the work hardening was analyzed. And a simulation model was established using ANSYS which can describe the relation between work-hardening effect and the pre-stress. It reveals the pre-stress restrains the work-hardening effect due to its influence on dislocation of surface materials, especially when the depth of cut is small.

Quench hardening of Sb0.2 Bi1.8Te3, Bi2Te2.8Se0.2 and Sn0.2 Bi1.8Te3 single crystals

The V2-VI3 intermetallics are narrow band gap semiconductors and well known for their thermoelectric properties. They therefore offer a convenient route to tune band gap for manipulating thermoelectric parameters. The V group element Sb can be fruitfully used to substitute Bi in various proportions thus forming a psuedobinary solid solution. The electronic in general and the thermoelectric properties in particular of this psuedobinary have been amply reported. However there are no reports found on mechanical properties. I have used Sb0.2 Bi1.8Te3, Bi2Te2.8Se0.2 and Sn0.2 Bi1.8Te3single crystals grown using Bridgman technique for the quenching treatment followed by hardness testing. Vickers hardness tests were conducted on the cleavage planes of the crystals quenched from various high temperatures and the quench hardenening coefficient values have been determined. The hardness tests were carried out at various applied loads also to explore load dependence of the measured hardness. The results are reported in the paper.

Modeling, optimization and control of an austenitization furnace for achieving target product toughness and minimizing energy use

Quench hardening is the process of heating finished or pre-finished steel parts to a specific temperature in order to reach a phase transformation of steel to austenite (austenitization) followed by quenching in oil, water or brine to induce desired metallurgical properties. During this process, both macroscopic quantities such as temperature and heat duty and microscopic variables, such as austenite grain size, determine the quality of the quenched product. In this paper, we propose a novel model-based approach for optimizing the energy input to an austenitization furnace system by capturing the essential physics at both the aforementioned length scales. The model predicts the energy consumption of the system, the part temperature distribution and the austenite grain size distribution as a function of the processing time and processing conditions. An optimization scheme is proposed to minimize the furnace energy consumption without compromising the part heating requirements and product quality.

Carbon ordering in martensite lattice under external stress: MD simulation

Rapid cooling of the Fe-C fcc solution leads to the formation of a phase called martensite, which has high mechanical properties. Martensitic transformation is the basis of quench steel hardening. Experimental investigation have shown that martensite lattice parameters a and c depend linearly on the carbon content. It is well known that under stress a martensite has the ability to plastically deform within a small range, despite the large value of the macroscopic yield strength. This effect is explained in different ways, mainly on the basis of dislocation theory. Professor M.Shtremel suggested an original treatment of the effect, based on the possibility of transferring the tetragonal axis of the martensite crystal. The experimental verification of the hypothesis is hampered by the difficulty in obtaining a crystal with one orientation. We investigated the influence of external stresses on carbon ordering in dilute Fe-C solid solutions and creation of tetrahedral distortion of crystal lattice in martensite. Molecular dynamics with embedded atom (EAM) interatomic potential have been used. According to simulations, interstitial carbon atoms migrate under compressive external stress applied along tetragonality direction from z-sublattice, and tetrahedral distortion of lattice changes its orientation to other ones. The simulation confirmed the validity of Shtremel’s theory. The influence of temperature and carbon concentration on this process was studied. The discrepancy between computer simulation results and theoretical data are discussed.

Model Predictive Control of the Exit Part Temperature for an Austenitization Furnace

Quench hardening is the process of strengthening and hardening ferrous metals and alloys by heating the material to a specific temperature to form austenite (austenitization), followed by rapid cooling (quenching) in water, brine or oil to introduce a hardened phase called martensite. The material is then often tempered to increase toughness, as it may decrease from the quench hardening process. The austenitization process is highly energy-intensive and many of the industrial austenitization furnaces were built and equipped prior to the advent of advanced control strategies and thus use large, sub-optimal amounts of energy. The model computes the energy usage of the furnace and the part temperature profile as a function of time and position within the furnace under temperature feedback control. In this paper, the aforementioned model is used to simulate the furnace for a batch of forty parts under heuristic temperature set points suggested by the operators of the plant. A model predictive control (MPC) system is then developed and deployed to control the the part temperature at the furnace exit thereby preventing the parts from overheating. An energy efficiency gain of 5.3 % was obtained under model predictive control compared to operation under heuristic temperature set points tracked by a regulatory control layer.

Influence of prior cold deformation on microstructure evolution of AISI D2 tool steel after hardening heat treatment

4mm thick plates of AISI D2 steel were subjected to two different percentage of cold rolling prior to quench hardening. Prior austenite grain size and volume fraction of carbides were reduced after hardening heat treatment for both 10% and 20% cold-rolled samples in comparison with non-deformed one. Hardness measurements revealed that pre-deformation resulted in a 3 to 4 HRC decrease. Scanning electron microscopy images revealed more uniform mean plate size of martensite for the cold rolled samples. The obtained results are analyzed in the framework of the existing theories on martensitic transformation and the influence of strain on second phase dissolution kinetics. The drop in hardness is related to the effect of pre-deformation on the dissolution rate of carbides. The volume fraction of martensite compared to non-deformed condition didn’t show dominant reduction.