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Heat Treatment of Metallic Materials in Modern Industry

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Metals and Alloys".

Deadline for manuscript submissions: closed (10 May 2023) | Viewed by 13220

Special Issue Editors

Department of Metals and Corrosion Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague, Czech Republic
Interests: intermetallic alloys; powder metallurgy; titanium alloys; aluminum alloys; mechanical alloying; spark plasma sintering; high-entropy alloys
Special Issues, Collections and Topics in MDPI journals
Faculty of Material Sciences and Technology of the STU in Trnava, J. Bottu 25, 917 24 Trnava, Slovakia
Interests: heat treatment of metals; thermochemical treatments; physical vapor deposition; microstructural analyses; microstructure–properties relationships
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Metals are the most widely used materials in various branches of the modern industry. For proper functionality of components made of metallic materials, the components must be subjected to different heat, thermochemical or surface treatments. For these purposes, a variety of equipment, such as industrial furnaces, laser generators, electron beam, physical vapor deposition devices, 3D printers, and others, are used. Thermal or thermochemical treatments evoke changes in bulk or superficial microstructures of metals and thereby modify their properties. Changes in both the microstructures and properties of metallic materials should be carefully controlled. Different techniques and devices such as light, electron, or confocal microscopes, hardness testers, and machines for wear and mechanical properties testing are utilized in order to evaluate these alterations.

Dr. Pavel Novak
Dr. Peter Jurči
Guest Editors

Manuscript Submission Information

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Keywords

  • heat treatment
  • metallic materials
  • thermochemical treatment
  • steels
  • nonferrous alloys
  • microstructure
  • mechanical properties

Published Papers (11 papers)

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Editorial

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2 pages, 177 KiB  
Editorial
Heat Treatment of Metallic Materials in Modern Industry
Materials 2022, 15(23), 8337; https://doi.org/10.3390/ma15238337 - 23 Nov 2022
Viewed by 694
Abstract
The Heat Treatment of Metallic Materials in Modern Industry is a Special Issue of the journal Materials, which aims to publish original full-length articles and review papers on basic and applied research centered around the given topic, and thereby make the understanding [...] Read more.
The Heat Treatment of Metallic Materials in Modern Industry is a Special Issue of the journal Materials, which aims to publish original full-length articles and review papers on basic and applied research centered around the given topic, and thereby make the understanding of the metallurgical background of the contemporary state of heat treatment techniques used in the industrial branches in the 21st century [...] Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)

Research

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24 pages, 5881 KiB  
Article
Numerical Modeling for the Prediction of Microstructure and Mechanical Properties of Quenched Automotive Steel Pieces
Materials 2023, 16(11), 4111; https://doi.org/10.3390/ma16114111 - 31 May 2023
Cited by 1 | Viewed by 729
Abstract
In this work, we present an efficient numerical tool for the prediction of the final microstructure, mechanical properties, and distortions of automotive steel spindles subjected to quenching processes by immersion in liquid tanks. The complete model, which consists of a two-way coupled thermal–metallurgical [...] Read more.
In this work, we present an efficient numerical tool for the prediction of the final microstructure, mechanical properties, and distortions of automotive steel spindles subjected to quenching processes by immersion in liquid tanks. The complete model, which consists of a two-way coupled thermal–metallurgical model and a subsequent (one-way coupled) mechanical model, was numerically implemented using finite element methods. The thermal model includes a novel generalized solid-to-liquid heat transfer model that depends explicitly on the piece’s characteristic size, the physical properties of the quenching fluid, and quenching process parameters. The resulting numerical tool is experimentally validated by comparison with the final microstructure and hardness distributions obtained on automotive spindles subjected to two different industrial quenching processes: (i) a batch-type quenching process with a soaking air-furnace stage prior to the quenching, and (ii) a direct quenching process where the pieces are submerged directly in the liquid just after forging. The complete model retains accurately, at a reduced computational cost, the main features of the different heat transfer mechanisms, with deviations in the temperature evolution and final microstructure lower than 7.5% and 12%, respectively. In the framework of the increasing relevance of digital twins in industry, this model is a useful tool not only to predict the final properties of quenched industrial pieces but also to redesign and optimize the quenching process. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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13 pages, 7107 KiB  
Article
The Efficient Way to Design Cooling Sections for Heat Treatment of Long Steel Products
Materials 2023, 16(11), 3983; https://doi.org/10.3390/ma16113983 - 26 May 2023
Viewed by 733
Abstract
To achieve the required mechanical properties in the heat treatment of steel, it is necessary to have an adequate cooling rate and to achieve the desired final temperature of the product. This should be achieved with one cooling unit for different product sizes. [...] Read more.
To achieve the required mechanical properties in the heat treatment of steel, it is necessary to have an adequate cooling rate and to achieve the desired final temperature of the product. This should be achieved with one cooling unit for different product sizes. In order to provide the high variability of the cooling system, different types of nozzles are used in modern cooling systems. Designers often use simplified, inaccurate correlations to predict the heat transfer coefficient, resulting in the oversizing of the designed cooling system or failure to provide the required cooling regime. This typically results in longer commissioning times and higher manufacturing costs of the new cooling system. Accurate information about the required cooling regime and the heat transfer coefficient of the designed cooling is critical. This paper presents a design approach based on laboratory measurements. Firstly, the way to find or validate the required cooling regime is presented. The paper then focuses on nozzle selection and presents laboratory measurements that provide accurate heat transfer coefficients as a function of position and surface temperature for different cooling configurations. Numerical simulations using the measured heat transfer coefficients allow the optimum design to be found for different product sizes. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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19 pages, 11101 KiB  
Article
Mechanical Properties of High Carbon Low-Density Steels
Materials 2023, 16(10), 3852; https://doi.org/10.3390/ma16103852 - 19 May 2023
Viewed by 931
Abstract
The paper presents the possibilities of heat treatment of low-density structural steels usable for springs. Heats have been prepared with chemical compositions 0.7 wt% C and 1 wt% C, as well as 7 wt% Al and 5 wt% Al. Samples were prepared from [...] Read more.
The paper presents the possibilities of heat treatment of low-density structural steels usable for springs. Heats have been prepared with chemical compositions 0.7 wt% C and 1 wt% C, as well as 7 wt% Al and 5 wt% Al. Samples were prepared from ingots weighing approximately 50 kg. These ingots were homogenised, then forged, and hot rolled. Primary transformation temperatures and specific gravity values were determined for these alloys. For low-density steels, there usually needs to be a solution to achieve the required ductility values. At cooling rates of 50 °C/s and 100 °C/s, the kappa phase is not present. A SEM analysed the fracture surfaces for the presence of transit carbides during tempering. The martensite start temperatures ranged from 55–131 °C, depending on the chemical composition. The densities of the measured alloys were 7.08 g/cm3 and 7.18 g/cm3, respectively. Therefore, heat treatment variation was carried out to achieve a tensile strength of over 2500 MPa, with ductility of almost 4%. Hardnesses above 60 HRC were achieved for 1 wt% C heats using the appropriate heat treatment. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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16 pages, 13790 KiB  
Article
Study on Austenite Transformation and Growth Evolution of HSLA Steel
Materials 2023, 16(9), 3578; https://doi.org/10.3390/ma16093578 - 07 May 2023
Cited by 2 | Viewed by 1116
Abstract
HSLA steel is widely used in various applications for its excellent mechanical properties. The evolution of austenite transformation and growth has been systematically studied in HSLA steel Q960 during the heating process. A thermal expansion instrument and optical microscope were adopted to analyze [...] Read more.
HSLA steel is widely used in various applications for its excellent mechanical properties. The evolution of austenite transformation and growth has been systematically studied in HSLA steel Q960 during the heating process. A thermal expansion instrument and optical microscope were adopted to analyze the kinetics of austenite transformation, which is a nonlinear continuous process and was accurately calculated by the lever rule based on the dilatation curve at the holding time within 10 min. The austenite growth behavior at temperatures above Ac3 was explored using TEM and DSC. The main precipitates in austenite were Nb-rich and Ti-rich (Nb, Ti)(C, N), and the particle size increased and amount decreased with the increase in the heating temperature, which resulted in the rapid growth of austenite. With the increase in holding temperature and time, the growth of austenite progressed through three stages, and a heat treatment diagram was established to describe this evolution. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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20 pages, 6379 KiB  
Article
Microstructure and Selected Properties of Iron–Vanadium Coatings Obtained by the Laser Processing of a VC Pre-Coat Applied on Steel—Single and Multiple Laser Tracks Study
Materials 2022, 15(18), 6417; https://doi.org/10.3390/ma15186417 - 15 Sep 2022
Viewed by 1077
Abstract
This paper presents the results of the microstructure, mechanical and physicochemical properties of coatings produced by the remelting of a VC pre-coat applied in the form of a paste on 145Cr6 steel. The remelting process was carried out using a diode laser beam. [...] Read more.
This paper presents the results of the microstructure, mechanical and physicochemical properties of coatings produced by the remelting of a VC pre-coat applied in the form of a paste on 145Cr6 steel. The remelting process was carried out using a diode laser beam. A laser device with a rated power of 3 kW was used. During these tests, a constant laser beam scanning speed of 3 m/min was used. The variable parameter was the laser beam power. Values of 500 W, 900 W and 1100 W were used. In the first stage of this study, single laser tracks were formed, and basic tests, such as on microstructure, microhardness and chemical composition, were performed. In the second stage of this study, multiple laser tracks were prepared using previously selected parameters. On such specimens, it was possible to test the same traits as for single tracks and, additionally, to perform corrosion and wear resistance tests. It was found that the obtained coatings have different properties than the base material. No primary vanadium carbides were found in the melted zone, but the proposed production method contributed to an increase in microhardness and wear resistance. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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14 pages, 2894 KiB  
Article
Effect of Annealing Temperature on Microstructure and Properties of Al/Mg Magnetic Pulse Welding Joints
Materials 2022, 15(16), 5519; https://doi.org/10.3390/ma15165519 - 11 Aug 2022
Cited by 3 | Viewed by 1317
Abstract
In this investigation, 1060Al/AZ31B welded joints were obtained by magnetic pulse welding technique. In order to test the microstructure and mechanical properties of the joints, the welded joints were annealed at different temperatures and then examined by optical microscopy (OM), scanning electron microscopy [...] Read more.
In this investigation, 1060Al/AZ31B welded joints were obtained by magnetic pulse welding technique. In order to test the microstructure and mechanical properties of the joints, the welded joints were annealed at different temperatures and then examined by optical microscopy (OM), scanning electron microscopy (SEM), energy spectrum analysis (EDS) and mechanical properties testing. The testing results of the welded joints annealed at different temperatures showed that the Al-Mg MPW welded joints were well bonded. The changing of the microstructure and mechanical properties of Al/Mg welded joints was not apparent under the temperature of 200 °C. However, Al12Mg17 intermetallic compound layer formed at 200 °C. Al12Mg17 and Al3Mg2 intermetallic compound layers formed at the temperature of 300 °C. The diffusion rate of Mg and Al elements is proportional to the annealing temperature and the intermetallic compounds layer is gradually formed. The microhardness near the interface decreased first and then increased on account of the brittleness of intermetallic compounds. In the tensile shear tests, the fracture mechanism of Al/Mg MPW welded joints were analyzed. When the temperature was lower than 200 °C the joints did not crack. At 200 °C and 250 °C, the joints fracture along the Al12Mg17-Al interface. The joint cracks along the interface of Al12Mg17-Al3Mg2 at the temperature of 300 °C. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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21 pages, 22229 KiB  
Article
Possibilities of a Direct Synthesis of Aluminum Alloys with Elements from Deep-Sea Nodules
Materials 2022, 15(13), 4467; https://doi.org/10.3390/ma15134467 - 24 Jun 2022
Cited by 1 | Viewed by 1260
Abstract
This work investigated the possibility of the direct preparation of aluminum alloys by aluminothermic reduction of deep-sea nodules with a high excess of aluminum. The process was found to be unable to obtain aluminum alloy, but an aluminum-rich manganese-based alloy was obtained instead, [...] Read more.
This work investigated the possibility of the direct preparation of aluminum alloys by aluminothermic reduction of deep-sea nodules with a high excess of aluminum. The process was found to be unable to obtain aluminum alloy, but an aluminum-rich manganese-based alloy was obtained instead, being composed of intermetallics. The alloy was characterized in the as-reduced state, as well as after crushing and sintering in the temperature range of 800–950 °C. The sample sintered at 900 °C was also heat-treated by annealing at 800 °C for 3 h and rapidly cooled. It was observed that with the increasing sintering temperature, the original matrix phase Al11Mn14 was transformed into a duplex matrix with a structure corresponding to Al11Mn14 and Al4Cu9, and this mixture was further transformed to the matrix with the structure corresponding to Al4Cu9. Furthermore, the mechanical properties and wear resistance of the samples were described. The highest microhardness was reached in the sample, which was annealed after sintering. Sintered samples reached a lower wear rate because of the fragmentation of brittle intermetallics during crushing. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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18 pages, 9533 KiB  
Article
A New Alloying Concept for Low-Density Steels
Materials 2022, 15(7), 2539; https://doi.org/10.3390/ma15072539 - 30 Mar 2022
Cited by 3 | Viewed by 1809
Abstract
This paper introduces a new alloying concept for low-density steels. Based on model calculations, samples—or “heats”—with 0.7 wt% C, 1.45 wt% Si, 2 wt% Cr, 0.5 wt% Ni, and an aluminium content varying from 5 to 7 wt% are prepared. The alloys are [...] Read more.
This paper introduces a new alloying concept for low-density steels. Based on model calculations, samples—or “heats”—with 0.7 wt% C, 1.45 wt% Si, 2 wt% Cr, 0.5 wt% Ni, and an aluminium content varying from 5 to 7 wt% are prepared. The alloys are designed to obtain steel with reduced density and increased corrosion resistance suitable for products subjected to high dynamic stress during operation. Their density is in the range from 7.2 g cm−3 to 6.96 g cm−3. Basic thermophysical measurements are carried out on all the heats to determine the critical points of each phase transformation in the solid state, supported by metallographic analysis on SEM and LM or the EDS analysis of each phase. It is observed that even at very high austenitisation temperatures of 1100 °C, it is not possible to change the two-phase structure of ferrite and austenite. A substantial part of the austenite is transformed into martensite during cooling at 50 °C s−1. The carbide kappa phase is segregated at lower cooling rates (around 2.5 °C s−1). Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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11 pages, 833 KiB  
Article
Assessment of Boron Diffusivities in Nickel Borides by Two Mathematical Approaches
Materials 2022, 15(2), 555; https://doi.org/10.3390/ma15020555 - 12 Jan 2022
Cited by 4 | Viewed by 1218
Abstract
In the work of this contribution, two kinetics models have been employed to assess the boron diffusivities in nickel borides in case of Inconel 718 alloy. The first approach, named the alternative diffusion model (ADM), used the modified version of mass conservation equations [...] Read more.
In the work of this contribution, two kinetics models have been employed to assess the boron diffusivities in nickel borides in case of Inconel 718 alloy. The first approach, named the alternative diffusion model (ADM), used the modified version of mass conservation equations for a three-phase system whilst the second one employed the mean diffusion coefficient (MDC) method. The boron diffusivities in nickel borides were firstly evaluated in the interval of 1123 to 1223 K for an upper boron concentration of 11.654 wt% in Ni4B3. The boron activation energies in the three phases (Ni4B3, Ni2B and Ni3B) were secondly deduced by fitting the values of boron diffusivities with Arrhenius relations. Finally, these values of energy were compared with the results from the literature for their experimental validation. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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19 pages, 11540 KiB  
Article
Structural Stability of the SUPER304H Steel Used in Energetics
Materials 2022, 15(2), 455; https://doi.org/10.3390/ma15020455 - 07 Jan 2022
Cited by 1 | Viewed by 1308
Abstract
This paper describes the influence of technological treatments (i.e., bending or welding) on the structural stability of SUPER304H austenitic steel used in reheaters and superheaters in fossil fuel power plants. Although the worldwide trend is transitioning to green power sources, the lifetime of [...] Read more.
This paper describes the influence of technological treatments (i.e., bending or welding) on the structural stability of SUPER304H austenitic steel used in reheaters and superheaters in fossil fuel power plants. Although the worldwide trend is transitioning to green power sources, the lifetime of existing power plants has to be prolonged until the transition is complete. Experimental material was tested in as-received state (straight tubes), bends, and homogeneous weld joints. Part of the specimens was solution-annealed after the technological operation. Afterwards, all the samples were thermally aged in furnace (650, 675 and 700 °C) for 7560–20,000 h. For comparison, bent specimens were placed at experimental sites on an operating powerplant for 10,000+ h. The long-term aging causes the formation of Cr-based carbides on the grain boundaries along with the Fe-Cr sigma phase. Combination of elevated temperature and residual stress accelerates formation of the sigma phase. This can be prevented by solution-annealing after bending. Mechanical properties were evaluated by Vickers hardness and tensile tests. The microstructure was observed using light optical microscopy (LOM) and scanning electron microscopy (SEM) with the energy-dispersive X-ray detector (EDXS). Electron backscatter diffraction (EBSD) and X-ray powder diffraction (XRPD) were used to characterize the brittle phases. Full article
(This article belongs to the Special Issue Heat Treatment of Metallic Materials in Modern Industry)
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