High Carbon Alloy Research Articles

Selective microzone remelting to reduce and refine the coarse primary carbides in high-carbon alloy steels

The coarse primary carbides in high-carbon alloy steels can significantly impair their overall performance. Reducing and refining the primary carbides efficiently are always of great significance in material processing. Here, an innovative approach ― the selective microzone remelting (SMR) method, is proposed to dramatically reduce and refine the coarse primary carbides. The method is achieved by utilizing an electric current and is facilitated with the substantial difference in electrical resistivity between carbides and the matrix phase. When a sample contains massive coarse primary carbides is subjected to an electric current, the high electrical resistivity of carbides leads to the selective remelting of local carbides before the sample reaches solidus temperature during heating while during cooling the big difference in electrical resistivity suppresses the carbides formation but promotes the austenite nucleation and growth. This mechanism has been validated through the successful treatment of M50 bearing steel, in which the large-sized blocky primary carbides were eliminated completely, leaving only small-sized eutectics with extremely thin lamellas. Besides, the microporosity in the as-cast sample has also been reduced significantly via SMR treatment. These studies demonstrated that the proposed SMR treatment can be a promising method to reduce and refine coarse precipitates formed during solidification in various alloys.

Transient Nucleate Boiling and Its Use for Thermomechanical Technologies Development

In the paper high temperature and low temperature intensive thermomechanical treatment is discussed. It is based on recently discovered new three physical principles that belong to the transient nucleate boiling process taking place in cold fluids. Such processes are considered in conditions when any film boiling during quenching in cold fluids is completely absent. That makes nucleate boiling very intensive, i.e. . The discoveries are used for direct quenching articles after forgings. The first is intensive high-temperature thermo-mechanical treatment (HTTMT). It is used for low and middle-carbon alloy steels. Forged steel parts are intensively quenched with a cooling interruption at the proper time to form surface compression residual stresses and fine bainitic microstructure at the core that increases radically surface life of forgings. The second method includes high-temperature and low temperature intensive thermo - mechanical treatment (LTTMT) of high carbon alloy steels with delaying martensitic transformation to make low-temperature thermo - mechanical treatment (LTTMT) possible. Then, after high temperature and low-temperature thermomechanical treatment, the steel goes to immediate tempering to create highly strengthened fine bainitic microstructure throughout the section of the steel part. A modified method of cooling time calculation, suitable for any size and form of steel part, is widely discussed in this paper.

Homogenization Path Based on 250 mm × 280 mm Bloom under Mixed Light and Heavy Presses: Simulation and Industrial Studies

This study proposed a new method for homogenizing continuous casting blooms based on solidification simulation calculations and industrial tests. The text describes a theoretical analysis of the solidification route of a cast billet of high-carbon alloy steel (B300A) under different process conditions. It summarizes the changing law of different under-pressure process parameters and under-pressure efficiency. The text also presents a solution to the seriousness of center shrinkage defects in the continuous casting of a large square billet of high-carbon alloy steel with the synergistic control technology of mixed light and heavy mixing under pressure. The study indicates that the center carbon segregation index of a high carbon steel continuous casting billet is 1.05, with a carbon extreme difference of not more than 0.08% and a proportion of 98.4%. Additionally, the center shrinkage is not more than a 0.5 level with a proportion of 99.5%. Meanwhile, the internal quality of cast billets has been improved, allowing for the rolling of large-size bars with a low consolidation ratio. The pass rate for internal ultrasonic flaw detection using the GB/T4162A grade is now higher than 99.95%, significantly reducing process costs and improving production efficiency for continuous casting and rolling.

MODELING OF PHASE TURNING PID HOUR OF PERMANENT COOLING OF HIGH-CARBON ALLOYING STEELS

On the basis of the author's analytical model together with finite element models, simulation of phase transformations during continuous cooling of high-carbon alloyed steels, intended for the manufacture of metal products of responsible purpose, in particular for the metallurgical and machine-building industries, was performed. The simulation results are summarized by constructing thermokinetic diagrams of austenite decay in the process of continuous cooling of steels 65Cr3SiMoV, 80Cr3MoV, 80Cr5MoV. The obtained results will be used during the adjustment of industrial modes of heat treatment of metal products of responsible purpose, in particular, back-up rolls of rolling mills. At the next stage of research, it is advisable to construct isothermal and structural diagrams of steels 65Cr3SiMoV, 80Cr3MoV, 80Cr5MoV including the determination of the distribution of structural components according to the depth of the strengthened layer (0–100 mm), which will allow to create scientifically based principles for improving the technology of heat treatment of support rolls rolling mills, which are made of high-carbon alloy steels.

Impact of powder properties on deoxidation and densification of carbon steels during powder bed fusion – Laser beam

This work examined the influence of powder properties on deoxidation and densification of carbon steels during powder bed fusion-laser beam (PBF-LB) at compositions between 0.06 and 1.1 wt% C. Analysis revealed that deoxidation was greatest in alloys with high carbon content, reaching losses of up to 440–600 ppm at compositions of 0.75 and 1.1 wt% C. This behavior was not due to enhanced oxygen removal by spatter, as spatter in high carbon alloys had less oxygen pickup (∼4% vs. ∼27%) and formed smaller oxide layers (∼42 nm vs. ∼82 nm). Instead, it was due to the high oxygen affinity of carbon at elevated temperature, which resulted in formation of gaseous carbon oxides that were subsequently removed by the process atmosphere. Regarding densification, powders with high avalanche energy (>7.75 mJ/kg), break energy (>4.75 mJ/kg), and particle size distribution (D10 > 25 μm) were more likely to form lack of fusion porosity at low energy input.

Design and analysis of newly developed two-wheeler shock absorber helical spring

The Elasticity property/Spring theory indicates that a long lasting spring is always showing small deflection and high stiffness and this property makes it comfortable for any applications. The present investigation deals with a comparative analysis carried out on the basis of sustainability of helical spring that is extensively used in suspension system, to increase the work efficiency of the shock absorber. A suspension system or a shock absorber is a mechanical device that is used to absorb shocks when riding in rough terrains. Stainless Steel grade (AISI316 & AISI302), High Carbon Steel (Music wire grade ASTM A228 & Hard drawn grade ASTM A227) and Alloy Steel (Chrome vanadium grade ASTM A231 & Chrome silicon grade ASTM A401) springs have been utilized throughout the study followed by applying compressive load. In order to enhance the mechanical property of the helical spring, alloy steel based material has been used instead of stainless steel. During this investigation a new shock absorber spring has been designed with the help of Solid Works software and the static structural analysis of the so formed model has been conducted via FEA.

RESEARCH OF THE THERMAL CYCLE ON THE SURFACE OF THE BILLET AS A CONSEQUENCE OF PLASTIC DEFORMATION DURING MECHANICAL PROCESSING

While the metallurgical characteristics of machined surfaces are constantly improving, there is still a lack of understanding regarding the thermal conditions in which these surfaces are in the process of interaction between the workpiece and the side surface. During machining of high-carbon alloys, very little is known about temperature changes in the internal volume of the machined part, where the workpiece material interacts with the cutting edge of the tool. In this work, the characteristics of the thermal field and the resulting surface metallurgy induced in high carbon alloys for cutting scenarios involving various combinations of thermomechanical boundary conditions were studied. The analysis of the development of the thermal field on the surface of the workpiece made it possible to reveal the heating and cooling rates caused by cutting, allowing to describe two different types of thermal cycle, with the structure Heating-Peak-Cooling and Heating-Quasi-isothermal Deformation-Cooling depending on the aggressiveness of the process. The subsurface thermal zone is found to be related to the deformation caused by cutting because it combines information about the magnitude of the thermal field and the speed of the process. It was found that the highest rate of heat generation caused by plastic deformation occurred in the thin surface layers at the beginning of the contact between the workpiece and the side surface, which was related to the conditions under which the white layers are generated. The analysis of the energy balance indicated the development of a less strong and less impulsive deformation process at greater depths below the surface, which was related to the mechanism of the formation of material resistance layers. Thus, the thermal effect on the processed surfaces was interconnected with their final metallurgical structure, which made it possible to deeply understand the physical conditions that arise when cutting high-carbon alloys.

FEM Simulation of Pulsed Laser Welding of High-Carbon Alloy Steel: Using Different Heat Source Models

FEM Simulation of Pulsed Laser Welding of High-Carbon Alloy Steel: Using Different Heat Source Models

PREDICTION OF THE STRUCTURAL STATE OF THE WORKING LAYER OF LARGE-SIZE ROLLS DURING THERMAL HARDENING

Problem statement. High-carbon steels, which are additionally alloyed with chromium, molybdenum, and vanadium, are used during the production of large-sized rolling rolls for hot deformation. Rolling rolls are subjected to significant loads during operation, so they must have sufficient hardness and resistance to wear. Steels of the type 65Cr3SiMoV, 80Cr3MoV, 80Cr5MoV have recently been used for the production of hot-formed rolling rolls, but despite this, their resistance to wear in harsh operating conditions is insufficient. There is no information in the literature about the peculiarities of the austenite decay kinetics of the specified rolled steels, therefore, this direction requires appropriate comprehensive research. Purpose. Development of a methodology for predicting the structural state of the working layer of large rolling rolls in the process of thermal strengthening of high-carbon alloy steels, taking into account the determining parameters of the manufacturing technology. Results. A methodology for modeling phase-structural transformations in the process of continuous cooling of high-carbon alloy steels was developed. For steels 65Cr3SiMoV, 80Cr3MoV, 80Cr5MoV were constructed thermokinetic diagrams and on their basis, the peculiarities of the formation of the structural state of the working layer of large rolling rolls (support, working) during thermal hardening were investigated. It has been established that the method of hardening by volumetric heating of support rolls made of 65Cr3SiMoV steel ensures the formation of a bainite structure over the entire normalized depth of their working layer. For working rolls made of 80Cr3MoV and 80Cr5MoV steels, the most effective method is hardening with differentiated heating, while in the latter case continuous cooling should be carried out at a slower speed.

Surface Topography Model of Ultra-High Strength Steel AF1410 Based on Dynamic Characteristics of Milling System

AF1410 is a low carbon high alloy ultra-high strength steel. It not only has high strength and high toughness, but also has a high stress corrosion resistance. However, due to the characteristics of hard quality and poor thermal conductivity, AF1410 is a difficult material to process. In the process of milling, the geometric factors of process parameters, the flexible deformation of milling cutter and the flutter of the process system all affect the surface roughness, which makes it difficult to predict the surface roughness of milling parts. In order to solve this problem, a prediction model for surface topography of ultrahigh strength steel AF1410 was studied. To solve this problem, this paper studies the formation of milling surface topography, considers the dynamic displacement of the milling system, proposes a modeling method of surface topography based on the dynamic characteristics of the milling system and forms a prediction model. On this basis, the surface topography of ultra-high strength steel is simulated and analyzed, and the accuracy of the model is verified by experiments. The study realizes the prediction of milling surface topography of AF1410 parts and reveals the formation mechanism of milling surface topography from geometric and physical perspectives.

Study of Manganese Recovery in the CaO-SiO<sub>2</sub>-MgO-Al<sub>2</sub>O<sub>3</sub>-MnO-Fe<sub>2</sub>O<sub>3</sub> System by Thermodynamic Simulation

The results of thermodynamic simulation of the manganese recovery in the CaO-SiO2-MgO-Al2O3-MnO-Fe2O3 system by carbon are presented. Parameters of the initial system are temperature range 1400-at a step of , a total pressure of 0.1 MPa, and N2. The composition of the oxide system is corresponded by the manganese ore (wt %) 1.1 MnO2, 44.3 MnO, 28.4 CaO, 9.3 SiO2, 5.4 MgO, 0.3 Al2O3, 11.2 Fe2O3 and silicomanganese slag. It contains (wt %) 16.3 MnO, 18.4 CaO, 52 SiO2, 7.8 MgO, 5.26 Al2O3, and 0.24 FeO. The amount of silicomanganese slag in the system was 0, 5, 12, and 25%. Carbon is used as a reducing agent. Its consumption is increased by 5% from the stoichiometry for the recovery of Fe and Mn and by 8% of the metal mass for the formation of iron, manganese, and silicon carbides. The simulation is carried out using HSC Chemistry 6.12 () software package. The thermodynamic characteristics of the Fe3C, Fe2O3, FeO, MnO2, Mn, Mn3C, Mn5C2, Mn7C3, Mn23C6, and SiC compounds existing in the database are refined. It was determined that an increase in the melt temperature from 1400 to increases the degree of manganese recovery (ηMn) for all compositions of the systems. An increase of the silicomanganese slag content in the mixture from 0 to 25% decreases ηMn from 89.3 to 85% at and from 95.8 to 91.5% at . The chemical composition of the high-carbon ferromanganese alloy is (wt %): 71.9-72.8 Mn, 16.6-17.9 Fe, 0.015-1.64 Si, and 9-. The simulation results can be used to develop a technology for producing a high-carbon ferromanganese when silicomanganese slag is involved in metallurgical processing.

Wear of Dry Friction Pairs Consisting of High-Carbon Chrome-Vanadium Steels and Hard Alloys

Wear of Dry Friction Pairs Consisting of High-Carbon Chrome-Vanadium Steels and Hard Alloys

Effect of plasma nitriding on M50 NiL steel – A review

Chemical Diffusion Process like Nitriding has important role in modern surface hardening. Plasma nitriding is one of the best method to improve surface hardness, wear and corrosion resistance of material, and also plasma nitriding improves surface properties. M50 NiL Steel is a low carbon high alloy steel with good strength, hardness, and wear and corrosion resistance at elevated temperatures. It is frequently utilised in the aerospace sector due to its unique features. To determine the corrosion and wear resistance of double element alternate implanted M50 NiL steel, detection methods such as scanning electron microscopy (SEM), X-Ray diffraction method (XRD), transmission electron microscopy (TEM), and potentio dynamic polarisation were utilised. The purpose of this paper is to identify the effects of plasma nitriding on M50 NiL Steel and to know the progress of surface hardening properties like micro hardness and wear for M50 NiL steel after plasma nitriding. The bearing made out of this steel is operated under heavy loads and high speeds in air craft engine. Effects of nitriding temperature on microstructure, micro hardness, and wear resistance of nitride layers with only a diffusion layer and no standard compound layer. and surface hardness is improved at low nitriding temperatures, When the nitriding temperature exceeds 575 °C, the nitride layer thickness increases, while the core and surface micro hardness drops. Mechanical Properties of nitride surfaces are studied by using Vickers hardness test and polarization tests. M50 NiL Steel was Plasma nitro carburized at low temperature and rare earth (RE) atoms are diffused into the specimen surface for better surface hardness and increased corrosion resistance. Some times to achieve exceptional properties duplex hardening is preferred and this process can be useful to obtain good hardness and same can be done for both hardened and case hardened bearing steels, with relative increase in rolling contact fatigue resistant and better tribological properties.

A steel-like unalloyed multiphase ductile iron

This work highlights a new process for direct manufacturing of ductile iron that is based on the innovative combined technology of quenching and partitioning, and low-temperature-transformation of nano bainite as used for high strength steels. In this process, a commercial unalloyed ductile iron is austenitized at 890 °C for 20 min, then rapidly quenched to 180 °C for 5 s, and finally partitioned at 220 °C for 240 min. A maximum tensile strength of more than 1600 MPa, a hardness of 55 HRC at an elongation in excess of 5%, and the number of repeat tensile fatigue failure of 2.5 × 104 cycles at a stress amplitude of 600 MPa, are achieved. This is comparable to those of a high strength carbon alloy steel. These properties are due to the synergistic strengthening and toughening effects of a multiphase structure comprising tempered martensite, bainitic ferrite and retained austenite in the matrix, and a spherical graphite morphology. This work provides a guidance on how to produce unique steel-like ductile iron with a high level of strength and acceptable toughness.

Metallurgical processing of converter slag

Converter slurries at modern metallurgical plants represent a significant part of metal-containing industrial waste with a high concentration of iron. Currently, there is a problem of their utilization and use as raw materials for metallurgy. The purpose of this work is to study the processes of briquetting and recovery of briquetted products, based on a mixture of converter slurries of gas purification and converter slags. When performing experimental studies on the preparation of sludge briquettes from a mixture of converter sludge of gas purification and converter slag, their metallization and reduction melting in laboratory conditions, the optimal composition of the components of the mixture of converter slag and gas purification sludge was determined by the percentage of iron, which is appropriate for use as a raw material for steel smelting. Experimental studies on the preparation of sludge-coal mixtures from dispersed metal-containing and carbon-containing industrial waste with stoichiometric coal consumption for the recovery of extracted metals have proved the possibility of obtaining sludge-coal briquettes, which are further subjected to metallization and reduction melting. Sequential processing of dispersed production waste, namely drying, metallization and reduction melting, allowed us to obtain at the final stage a metal sample that corresponds to high-quality steel in its composition. Based on the analysis of the results of experimental studies, the technology of reducing melting of metal-containing waste has been developed. As a result of the implementation of the technology, high-quality steels and alloys can be obtained without carburizing the metal, bypassing the production stages of cast iron and high-carbon alloys. The content of harmful impurities of sulfur and phosphorus meets the technical requirements of high-quality steel. The proposed technology for processing slag and sludge from oxygen-converter production will reduce the volume of accumulated production waste.

Role of carbides on hot deformation behavior and dynamic recrystallization of hard-deformed superalloy U720Li

Cracks are easy to occur during cogging of U720Li ingots due to the high deformation resistance and poor hot ductility. In this paper, the low-carbon alloy (0.014 wt% C) and high-carbon alloy (0.071 wt% C) ingots were fully homogenized. The effect of carbides on hot deformation behavior and dynamic recrystallization (DRX) of as-homogenized U720Li alloy was investigated with aim of providing some guidance for improving hot working performance of such hard-deformed superalloys. It has been found that the blocky MC carbide is the major form of carbon in both alloys. Compared with low-carbon alloy, the size, number density and area fraction of MC carbides in high-carbon alloy are much greater, but those of γ′ are similar. The existence of more MC carbides leads to finer initial grains in the high-carbon alloy. During compression deformation of both alloys at 1060 °C, intergranular cracking occurred preferentially along initial grain boundaries (GBs), but cracking of the high-carbon alloy occurred at larger strains than that of low-carbon alloy. Before the occurrence of cracking, the yield and flow stress of high-carbon alloy were obviously lower than those of low-carbon alloy. An interesting phenomenon was discovered that the DRX always occurred preferentially around the MC carbides. Based on this phenomenon and electron backscatter diffraction analysis, the MC carbides were assumed to act as nucleation sites during initiation of DRX by a particle stimulated dynamic recrystallization mechanism. In addition, initial GBs are also preferential sites for DRX initiation. The greater size and number density of MC carbides and finer initial grains significantly increased the stored energy and nucleation sites, which distinctly promoted DRX in the high-carbon alloy. The faster DRX is the major contributor in reducing deformation resistance and cracking of the high-carbon alloy.

Pulse laser welding of high carbon alloy steel: assessment of melt pool geometry and mechanical performance

Pulse laser welding of high carbon alloy steel: assessment of melt pool geometry and mechanical performance

Increasing Casting Speed in High Carbon and Micro Alloy DIN EN ISO 16120-2: 2011-C66D Steels

Different parameters can be used together in the continuous casting process known as an important steel production stage in the world. It is important to use metallurgical appropriate parameters to meet the product properties. Many innovations have been made in the continuous casting process from past to present. It is known that studies are carried out on many effective topics such as steel analysis, refractory materials, continuous casting parameters, in order to make the proper solidification that will meet the needs with its continuous casting capabilities. When continuous casting parameters are examined; the casting speed parameter was found to be effective in terms of quality needs in macro samples. Therefore, in this study, the effect of the increase of casting speed parameters on the quality of macro samples was investigated. As a method; in high carbon, micro-alloyed DIN EN ISO 16120-2: 2011-C66D quality steels, in different castings, this parameter was changed and macro samples were taken and evaluated in terms of quality needs. When macro sample quality results are compared; the effect of casting speed was observed. In this study; the effect of the increase in casting speed in continuous billet casting facility on optimum metallographic and physical quality has been investigated and the results have been interpreted.

Laser welding of ASTM Corten A588 grade steel - a case study

Corten A588 grade structural steel is a high strength low carbon alloy with high atmospheric corrosion resistance. A significant defect in Corten A588 grade steel is its mechanical, metallurgical and corrosion properties gets altered and gets affected after post welding process. This is due to the Corten A588 grade steel during welding process gets exposed to high temperature in and around the weld zone making it less reliable after the fabrication. Laser beam welding (LBW) is an autogenous welding method in which the heat affected zone and weld zone formed is considered to be very narrow. In this research Carbon dioxide laser beam welding (CO2 - LBW) is performed on a 2 mm thick Corten A588 grade steel under optimal welding condition. Then the mechanical property such as tensile, impact, bending and hardness of the LBW Corten A588 grade steel weld joints are evaluated as per ASTM standards. This research gives detailed information about laser beam welding (CO2 - LBW) of Corten A588 grade steel, various issues faced by the material and helps in widening the applications of this material in various other sectors.

Experimental study on heat treatment and mechanical behaviour of M50 NiL steel – A review

M50 NiL Steel is low carbon high alloy steel with good strength, toughness, better wear and corrosion resistance at elevated temperature, because of this properties it is widely used in aerospace industry. Detection methods such as SEM, XPS, AES and TEM, and potentio dynamic polarization are used to find out corrosion resistance of double element alternate implanted M50 NiL steel. Hot Compression tests are used to study the behaviour of M50 NiL Steel during deformation. Potentio dynamic curves and electrochemical impedance spectroscopy are used to evaluate the corrosion properties for untreated and carbon ion implanted steels. Development of latest method like LPC Technology to meet the client requirements in industry, where the furnace design and operation has very crucial importance because of its flexibility to perform standard vacuum heat treatment and carburizing cycles. Different treatments like solution and tempering, gives precipitation behaviours of carbides [(V, Cr)-rich MC, (Mo, Fe)-rich M2C, Fe-rich M3C and (Fe, Cr)-rich M7C3] in M50 NiL Carburized Steel after heat treatment. The wear resistance behaviour of nitrided steel pieces will be enhanced by plasma nitriding process, where ultra fine grains and smooth surface of nitrided layer, posses high wear resistance. The mechanical behaviour of M50 Nil steel under carburizing and nitriding (dual) treatments, at the temperatures from 890 °C to 900 °C is helpful and Microstructure analysis can be characterized by XRD and SEM, TEM Methods. The objective of the paper is to review the mechanical behaviour and heat treatment process for better performance of M50 NiL Steel under various heat treatments and ion implementation methods.