Materials

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8 pages, 230 KiB

Open AccessEditorial

Development of Laser Welding and Surface Treatment of Metals

by Aleksander Lisiecki

Materials 2022, 15(5), 1765; https://doi.org/10.3390/ma15051765 - 26 Feb 2022

Cited by 10 | Viewed by 2293

Abstract

This Special Issue on Development of Laser Welding and Surface Treatment of Metals contains as many as twenty-two research articles mainly related to the application of lasers, but also on other welding processes that may be competitive to laser technologies under specific conditions. [...] Read more.

This Special Issue on Development of Laser Welding and Surface Treatment of Metals contains as many as twenty-two research articles mainly related to the application of lasers, but also on other welding processes that may be competitive to laser technologies under specific conditions. Despite the introduction of lasers for material processing in the 1960s, the continuous development of laser devices also leads to the development and expansion of laser technology applications. This Special Issue is a compendium of knowledge in the field of fusion welding, the manufacturing of surface layers and coatings with increased wear resistance and tribological characteristics, as well as corrosion resistance and the characterization of coatings and surface layers. The topics of the presented research articles include aspects related to laser welding (eight articles), especially technological conditions, the properties of different types of joints, and analytical and numerical aspects of modelling the laser heat sources. The second dominant issue concerns laser cladding and laser surface treatment of different ferrous and nonferrous metallic and composite materials (six articles). In addition, there are interesting results of the study of fusion welding under forced cooling of the deposit or underwater conditions (four articles), results on the characterization of wear resistance coating produced by different technologies that can be competitive for laser cladding (three articles), and an original study on local strengthening of the thin-walled structure by laser treatment (one article). This Special Issue provides very wide and valuable knowledge based on theoretical and empirical study in the field of laser and fusion welding, laser and related coating technologies, characterization of coatings, and wear phenomena. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

Research

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25 pages, 12010 KiB

Open AccessArticle

Hybrid Laser Deposition of Composite WC-Ni Layers with Forced Local Cryogenic Cooling

by Aleksander Lisiecki and Dawid Ślizak

Materials 2021, 14(15), 4312; https://doi.org/10.3390/ma14154312 - 02 Aug 2021

Cited by 9 | Viewed by 1580

Abstract

The purpose of this study was to demonstrate the effect of forced and localized cooling by nitrogen vapours stream under cryogenic conditions during laser deposition of WC-Ni powder on the geometry, microstructure of clad layers and dry sliding wear resistance of the coatings. [...] Read more.

The purpose of this study was to demonstrate the effect of forced and localized cooling by nitrogen vapours stream under cryogenic conditions during laser deposition of WC-Ni powder on the geometry, microstructure of clad layers and dry sliding wear resistance of the coatings. For this purpose, comparative tests were performed by conventional laser cladding at free cooling conditions in ambient air and by the developed novel process of laser deposition with additional localized cooling of the solidifying deposit by nitrogen vapours stream. Due to presence of gaseous nitrogen in the region of the melt pool and solidifying deposit, the process was considered as combining laser cladding and laser gas nitriding (performed simultaneously), thus the hybrid process. The influence of the heat input and cooling conditions on the geometrical features, dilution rate, share of carbides relative to the matrix, and the fraction share of carbides, as well as hardness profiles on cross sections of single stringer beads was analysed and presented. The XRD, EDS analysis and the sieve test of the experimental powder were used to characterize the composite WC-Ni type powder. The OM, SEM, EDS and XRD test methods were used to study the microstructure, chemical and phase composition of clad layers. Additionally, ball-on-disc tests were performed to determine the wear resistance of representative coatings under dry sliding conditions. The results indicate that the novel demonstrated technique of localized forced cooling of the solidifying deposit has advantageous effect, because it provides approximately 20% lower penetration depth and dilution, decreases tendency for tungsten carbides decomposition, provides more uniform distribution and higher share of massive eutectic W₂C-WC carbides across the coating. While the conventionally laser cladded layers show tendency for decomposition of carbide particles and resolidifying dendritic complex carbides mainly M₂C, M₃C and M₇C₃ containing iron, nickel, and tungsten, and with Ni/Ni₃B matrix. The quantitative relationship between heat input, cooling conditions and the carbides grain size distribution as well as carbides share in relation to the matrix was determined. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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16 pages, 5568 KiB

Open AccessArticle

Technology and Properties of Peripheral Laser-Welded Micro-Joints

by Szymon Tofil, Hubert Danielewski, Grzegorz Witkowski, Krystian Mulczyk and Bogdan Antoszewski

Materials 2021, 14(12), 3213; https://doi.org/10.3390/ma14123213 - 10 Jun 2021

Cited by 4 | Viewed by 2108

Abstract

This article presents the results of research on the technology and peripheral properties of laser-welded micro-couplings. The aim of this research was to determine the characteristics of properly made joints and to indicate the range of optimal parameters of the welding process. Thin-walled [...] Read more.

This article presents the results of research on the technology and peripheral properties of laser-welded micro-couplings. The aim of this research was to determine the characteristics of properly made joints and to indicate the range of optimal parameters of the welding process. Thin-walled AISI 316L steel pipes with diameters of 1.5 and 2 mm used in medical equipment were tested. The micro-welding process was carried out on a SISMA LM-D210 Nd:YAG laser. The research methods used were macroscopic and microscopic analyses of the samples, and assessment of the distribution of elements in the weld, the distribution of microhardness and the tear strength of the joint. As a result of the tests, the following welding parameters are recommended: a pulse energy of 2.05 J, pulse duration of 4 ms and frequency of 2 Hz, beam focusing to a diameter of 0.4 mm and a rotation speed of 0.157 rad/s. In addition, the tests show good joint properties with a strength of more than 75% of the thinner pipe, uniform distribution of alloying elements and a complex dendritic structure characteristic of pulse welding. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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23 pages, 10185 KiB

Open AccessArticle

Behavior of Weld to S960MC High Strength Steel from Joining Process at Micro-Jet Cooling with Critical Parameters under Static and Fatigue Loading

by Tadeusz Szymczak, Bożena Szczucka-Lasota, Tomasz Węgrzyn, Bogusław Łazarz and Adam Jurek

Materials 2021, 14(11), 2707; https://doi.org/10.3390/ma14112707 - 21 May 2021

Cited by 9 | Viewed by 1796

Abstract

The paper is focused on testing the weld of the S960MC steel produced at the micro-jet cooling under static and fatigue loading at critical parameters. This kind of material was in the form of a sheet with a thickness equal to 2 mm. [...] Read more.

The paper is focused on testing the weld of the S960MC steel produced at the micro-jet cooling under static and fatigue loading at critical parameters. This kind of material was in the form of a sheet with a thickness equal to 2 mm. The joint was obtained using three different types of welding wires: EDFK 1000, Union NiMoCr and Union X96 at the same parameters of the process. The joints were examined using non-destructive and destructive tests. The results from non-destructive experiments enable us to assess the quality of the welds directly before the joining process. In contrast, the destructive one allows following welds behavior under different loading conditions with their critical parameters. The bending experiments confirmed the good plastic properties of the weld, expressed by no cracks in the region tested in many variants of the joint manufactured. The results from static tests indicated a significant reduction of mechanical parameters of the weld in comparison to the base metal, expressed by 50% differences. Fatigue data have enabled us to follow the welding behavior at the increasing amplitude of axial stress up to fracture at constant amplitude value covering the following values of stress 650 MPa–100 MPa. Variations of total energy are presented at different values of several cycles up to fracture. Fracture regions are collected for analysis of the joint region features under cyclic loading. They have indicated differences in weld cracking depended on the stress level. Finally, the Wöhler S-N curve of the weld was determined, indicating the value of the fatigue limit of the weld tested, i.e., 100 MPa. The weld at the Union NiMoCr welding wire was indicated as the joint having the highest resistance on static and fatigue loadings. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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16 pages, 8425 KiB

Open AccessArticle

High Martensitic Steel after Welding with Micro-Jet Cooling in Microstructural and Mechanical Investigations

by Bożena Szczucka-Lasota, Tomasz Węgrzyn, Tadeusz Szymczak and Adam Jurek

Materials 2021, 14(4), 936; https://doi.org/10.3390/ma14040936 - 16 Feb 2021

Cited by 6 | Viewed by 1893

Abstract

Modern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the [...] Read more.

Modern means of transport will play a significant role in the smart city. In the automotive industry, high-strength steels such as Docol are employed more often. This kind of material is relatively not very well weldable. The main reason is related to the Heat Affect Zone, the region in which cracks occur. Another disadvantage is connected with differences in values of ultimate strength of parent and weld material. The differences can be diminished using the correct welding process, which employs nickel and molybdenum electrode wires at much lower sulfur content. The weld metal deposit contains mainly martensite and bainite with coarse ferrite, while the parent material contains mainly martensite and rather fine ferrite. New technology, micro-jet cooling after the joining process enables to obtain the microstructure of weld metal deposit at acceptable parameters. Welding with micro-jet cooling could be treated as a very promising welding Docol steels process with high industrial application. Results of non-destructive inspections on macro samples corresponded with further destructive test results (tensile strength, hardness, fatigue, metallographic structure analyses). This article aims to verify fatigue behavior of Docol 1200 M steel after welding supported by the cooling using the micro-jet technique. For the first time, micro-jet cooling was used to weld this kind of steel to check the mechanical properties of the joint, especially to determine the fatigue limit. This study is formulated as follows: investigating fatigue resistance of the Docol 1200 M weld manufactured at the cooling process with micro-jets. The joints were produced in the MAG (Metal Active Gas) technology modified by micro-jet cooling. The results collected in the fatigue test were processed in the form of the Wöhler’s S–N diagram following the fatigue limit of the weld examined. All data have indicated the possibility of obtaining a new method of welded joints with high fatigue limit minimum of 480 MPa. It could be important to achieve a tensile strength of 700 MPa while maintaining the best relative elongation at the level of the base material. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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14 pages, 3979 KiB

Open AccessArticle

Experimental Analysis of Tribological Processes in Friction Pairs with Laser Borided Elements Lubricated with Engine Oils

by Janusz Lubas, Wojciech Szczypiński-Sala, Paweł Woś, Edyta Zielińska and Krzysztof Miernik

Materials 2020, 13(24), 5810; https://doi.org/10.3390/ma13245810 - 19 Dec 2020

Cited by 6 | Viewed by 1564

Abstract

The present study discusses the influence of engine oils on the tribological parameters of sliding couples with laser borided surface layer. The borided layer was formed on specimens made from AISI 5045 steel by laser remelting of a surface layer coated with amorphous [...] Read more.

The present study discusses the influence of engine oils on the tribological parameters of sliding couples with laser borided surface layer. The borided layer was formed on specimens made from AISI 5045 steel by laser remelting of a surface layer coated with amorphous boron. The sliding friction and wear process was carried out on the pairs with AISI 5045 steel and SAE-48 bearing alloys which were lubricated with 5W-40 and 15W-40 engine oils. The investigation showed significant differences in the friction coefficient and temperature in the tested pairs with the laser borided surface layer. In the couples lubricated with 5W-40 engine oil, the tested parameter of friction was higher than in the couples lubricated with 15W-40 engine oil. The couples lubricated with 5W-40 engine oil showed more intensive wear of SAE-48 bearing alloy in contact with the laser borided surface layer than the pairs lubricated with 15W-40 engine oil. The laser borided surface layer used in friction pairs leads to the destruction of the lubricating properties of engine oils and reduces its resistance to scuffing. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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17 pages, 11887 KiB

Open AccessArticle

Investigation of Welds and Heat Affected Zones in Weld Surfacing Steel Plates Taking into Account the Bead Sequence

by Miloš Mičian, Jerzy Winczek, Marek Gucwa, Radoslav Koňár, Miloslav Málek and Przemysław Postawa

Materials 2020, 13(24), 5666; https://doi.org/10.3390/ma13245666 - 11 Dec 2020

Cited by 10 | Viewed by 2937

Abstract

In this paper, the experimental investigation results of the bead sequence input on geometry, structure, and hardness of surfaced layers after multi-pass weld surfacing are analyzed. Three S355 steel plates surfaced by GMAW (Gas Metal Arc Welding) were tested with three different combinations [...] Read more.

In this paper, the experimental investigation results of the bead sequence input on geometry, structure, and hardness of surfaced layers after multi-pass weld surfacing are analyzed. Three S355 steel plates surfaced by GMAW (Gas Metal Arc Welding) were tested with three different combinations of six beads. The geometric, structural, and hardness analysis was carried out in the cross-section of the plates in the middle of the welded layers. The dimensions of padded layers, fusion and heat-affected zone, as well as the individual padded weld were evaluated. On the basis of metallographic samples, qualitative and quantitative structure analysis was performed. Hardness measurements in surfacing welds and heat-affected zones in the tested cross-sections of the surfacing layers were carried out. A comparative analysis of structure and hardness, taking into account the thermal implications of the bead sequence, allowed for the formulation of conclusions. Comparative studies have shown differences in properties between heat-affected zones (HAZ) for individual surfacing sequences. These differences were mainly in the dimensions of the surfacing layers, the share of structural components, as well as the uniformity of hardness distributions. Finally, the most favorable sequence in terms of structure and hardness distribution, maximum hardness, and range of hardness has been indicated. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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26 pages, 17227 KiB

Open AccessArticle

Comparison of Properties of Hardfaced Layers Made by a Metal-Core-Covered Tubular Electrode with a Special Chemical Composition

by Artur Czupryński

Materials 2020, 13(23), 5445; https://doi.org/10.3390/ma13235445 - 29 Nov 2020

Cited by 22 | Viewed by 3334

Abstract

In this article, the results of research on the metal-mineral-type abrasive wear of a wear-resistant plate made by a tubular electrode with a metallic core and an innovative chemical composition using the manual metal arc hardfacing process were presented. The properties of the [...] Read more.

In this article, the results of research on the metal-mineral-type abrasive wear of a wear-resistant plate made by a tubular electrode with a metallic core and an innovative chemical composition using the manual metal arc hardfacing process were presented. The properties of the new layer were compared to the results of eleven wear plates manufactured by global suppliers, including flux-cored arc welding gas-shielded (FCAW-GS, Deposition Process Reference Number: 138), flux-cored arc welding self-shielded (FCAW-SS, Deposition Process Reference Number: 114), automated hardfacing, and manual metal arc welding (MMAW, Deposition Process Reference Number: 111) hardfacing T Fe15 and T Fe16 alloys, according to EN 14700:2014. Characterization of the hardfaced layers was achieved by using hardness tests, optical microscopy, confocal microscopy, scanning electron microscopy, and EDS (Energy Dispersive Spectroscopy) and X-ray diffraction analyses. Based on wear resistance tests in laboratory conditions, in accordance with ASTM G65-00: Procedure A, and surface layer hardness tests, in accordance with PN-EN ISO 6508-1, the wear plates most suitable for use in metal-mineral conditions were chosen. The results demonstrated the high metal-mineral abrasive wear resistance of the deposit weld metal produced by the new covered tubular electrode. The tubular electrode demonstrated a high linear correlation between the surface wear resistance and the hardness of the metal matrix of the tested abrasive wear plates. In addition to hardness, size, shape, the dispersion of strengthening phases, and the base metal content, depending on hardfacing technology and technological parameters, impact wear resistance is represented by volumetric loss caused by effect-free or constrained dry abrasive medium contact. The presented results can be used in machine part material selection and wear planning for applications in inspection, conservation, and regeneration interval determination. The obtained results will be applied in a real-time wear rate prediction system based on the measurement of the working parameters. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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15 pages, 20102 KiB

Open AccessArticle

Laser Dissimilar Welding of AISI 430F and AISI 304 Stainless Steels

by Krzysztof Pańcikiewicz, Aleksandra Świerczyńska, Paulina Hućko and Marek Tumidajewicz

Materials 2020, 13(20), 4540; https://doi.org/10.3390/ma13204540 - 13 Oct 2020

Cited by 54 | Viewed by 3882

Abstract

A dissimilar autogenous laser welded joint of AISI 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainless steel was manufactured. The welded joint was examined by non-destructive visual testing and destructive testing by macro- and microscopic examination and hardness measurements. With [...] Read more.

A dissimilar autogenous laser welded joint of AISI 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainless steel was manufactured. The welded joint was examined by non-destructive visual testing and destructive testing by macro- and microscopic examination and hardness measurements. With reference to the ISO 13919-1 standard the welded joint was characterized by C level, due to the gas pores detected. Microscopic observations of AISI 430F steel revealed a mixture of ferrite and carbides with many type II sulfide inclusions. Detailed analysis showed that they were Cr-rich manganese sulfides. AISI 304 steel was characterized by the expected austenitic microstructure with banded δ-ferrite. Martensitic microstructure with fine, globular sulfide inclusions was observed in the weld metal. The hardness in the heat-affected zone was increased in the martensitic steel in relation to the base metal and decreased in the austenitic steel. The hardness range in the weld metal, caused by chemical inhomogeneity, was 184–416 HV0.3. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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20 pages, 6352 KiB

Open AccessArticle

Mechanical and Corrosion Properties of Laser Surface-Treated Ti13Nb13Zr Alloy with MWCNTs Coatings

by Beata Majkowska-Marzec, Patryk Tęczar, Michał Bartmański, Bartosz Bartosewicz and Bartłomiej J. Jankiewicz

Materials 2020, 13(18), 3991; https://doi.org/10.3390/ma13183991 - 09 Sep 2020

Cited by 10 | Viewed by 2456

Abstract

Titanium and its alloys is the main group of materials used in prosthetics and implantology. Despite their popularity and many advantages associated with their biocompatibility, these materials have a few significant disadvantages. These include low biologic activity—which reduces the growth of fibrous tissue [...] Read more.

Titanium and its alloys is the main group of materials used in prosthetics and implantology. Despite their popularity and many advantages associated with their biocompatibility, these materials have a few significant disadvantages. These include low biologic activity—which reduces the growth of fibrous tissue and allows loosening of the prosthesis—the possibility of metallosis and related inflammation or other allergic reactions, as well as abrasion of the material during operation. Searching for the best combinations of material properties for implants in today′s world is not only associated with research on new alloys, but primarily with the modification of their surface layers. The proposed laser modification of the Ti13Nb13Zr alloy with a carbon nanotube coating is aimed at eliminating most of the problems mentioned above. The carbon coating was carried out by electrophoretic deposition (EPD) onto ground and etched substrates. This form of carbon was used due to the confirmed biocompatibility with the human body and the ability to create titanium carbides after laser treatment. The EPD-deposited carbon nanotube coating was subjected to laser treatment. Due to high power densities applied to the material during laser treatment, non-equilibrium structures were observed while improving mechanical and anti-corrosive properties. An electrophoretically deposited coating of carbon nanotubes further improved the effects of laser processing through greater strengthening, hardness or Young′s modulus similar to that required, as well as led to an increase in corrosion resistance. The advantage of the presented laser modification of the Ti13Nb13Zr alloy with a carbon coating is the lack of surface cracks, which are difficult to eliminate with traditional laser treatment of Ti alloys. All samples tested showed contact angles between 46° and 82° and thus, based on the literature reports, they have hydrophilic surfaces suitable for cell adhesion. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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23 pages, 6416 KiB

Open AccessArticle

Feasibility Evaluation of Local Laser Treatment for Strengthening of Thin-Walled Structures from Low-Carbon Steel Subjected to Bending

by Oleksandr Kapustynskyi, Nikolaj Višniakov, Darius Zabulionis and Artur Piščalov

Materials 2020, 13(14), 3085; https://doi.org/10.3390/ma13143085 - 10 Jul 2020

Cited by 5 | Viewed by 1768

Abstract

This paper is devoted to investigating numerically, by finite element analysis (FEA), and analytically the influences and effects of laser processing of the surface of thin-plate, low-carbon structural steel. The plate mechanical properties—axial and flexural stiffnesses, force-deflection behavior and cross-section force-strain behavior—are investigated [...] Read more.

This paper is devoted to investigating numerically, by finite element analysis (FEA), and analytically the influences and effects of laser processing of the surface of thin-plate, low-carbon structural steel. The plate mechanical properties—axial and flexural stiffnesses, force-deflection behavior and cross-section force-strain behavior—are investigated after different laser treatments. An analytical methodology of the estimation of the cross-section area of the laser-processed metal is also proposed in the present article, that can be applied to choosing the reasonable distance between the centers of the laser-processed tracks. The methodology takes into account the width of the laser-processed tracks and the distances between these tracks. The experimental, finite element numerical and analytical analyses showed that the laser treatments of the surface of the steel plate increase the yield point of the laser-processed metal and the axial and flexural stiffnesses of the plate. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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16 pages, 8629 KiB

Open AccessArticle

Autogenous Fiber Laser Welding of 316L Austenitic and 2304 Lean Duplex Stainless Steels

by Michał Landowski, Aleksandra Świerczyńska, Grzegorz Rogalski and Dariusz Fydrych

Materials 2020, 13(13), 2930; https://doi.org/10.3390/ma13132930 - 30 Jun 2020

Cited by 69 | Viewed by 4811

Abstract

This study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non-destructive testing (visual [...] Read more.

This study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non-destructive testing (visual and penetrant), destructive testing (static tensile test, bending test, and microhardness measurements) and structure observations (macro- and microscopic examinations, SEM, element distribution characteristics, and ferrite content measurements). Non-destructive tests and metallographic examinations showed that the welded joints meet the acceptance criteria for B level in accordance with EN ISO 13919–1 standard. Also the results of the destructive tests confirmed the high quality of the joints: specimens were fractured in base material with lower strength—316L austenitic stainless steel and a 180° bending angle was obtained confirming the high plasticity of the joints. Microscopic examination, SEM and EDS analysis showed the distribution of alloying elements in joints. The microhardness of the autogenous weld metal was higher by about 20 HV0.2 than that of the lean duplex steel. Ferrite content in the root was about 37% higher than in the face of the weld. The Schaeffler phase diagram was used to predict the phase composition of the welded joints and sufficient compliance with the magnetic method was found. The presented procedure can be used for welding of 316L–2304 stainless steels dissimilar welded joints of 8 mm thickness without ceramic backing. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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24 pages, 10987 KiB

Open AccessArticle

Heat Source Models in Numerical Simulations of Laser Welding

by Tomasz Kik

Materials 2020, 13(11), 2653; https://doi.org/10.3390/ma13112653 - 10 Jun 2020

Cited by 78 | Viewed by 8204

Abstract

The article presents new possibilities for modifying heat source models in numerical simulations of laser welding processes conducted using VisualWeld (SYSWELD) software. Due to the different power distributions and shapes of a laser beams, it was necessary to propose a modification of heat [...] Read more.

The article presents new possibilities for modifying heat source models in numerical simulations of laser welding processes conducted using VisualWeld (SYSWELD) software. Due to the different power distributions and shapes of a laser beams, it was necessary to propose a modification of heat source models and methods of defining the heat introduced into a welded material in the case of simulations of welding processes using solid-state and high-power diode lasers. A solution was proposed in the form of modification of predefined heat source models in the case of simulations of welding processes using solid-state disc lasers and high-power diode lasers (HPDL). Based on the results of metallographic tests and the acquisition of thermal cycles of real laser welding processes, the process of calibration and validation of the proposed models of heat sources depending on the type of device used as well as the obtained shapes of fusion beads was carried out. The purpose and assumptions of this approach towards creating heat sources were also reported, comparing exemplary stresses and cumulative plastic strain distributions for the calculation variant using a standard and modified heat source model. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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11 pages, 5506 KiB

Open AccessArticle

Investigation on the Microstructure and Wear Behavior of Laser-Cladded High Aluminum and Chromium Fe-B-C Coating

by Jingjing Li, Jiang Ju, Weiwei Chang, Chao Yang and Jun Wang

Materials 2020, 13(11), 2443; https://doi.org/10.3390/ma13112443 - 27 May 2020

Cited by 8 | Viewed by 1857

Abstract

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses [...] Read more.

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses good metallurgical bond with the substrate. The microstructure is mainly composed of α-(Fe, Cr, Al) lath martensite, orthorhombic M₂B boride, orthogonal M₃C₂, and orthorhombic M₇C₃ carbides. The microhardness of the coating can reach 620 HV which is 3.3-times higher than that (190 HV) of the substrate. The coating shows a lower friction coefficient of 0.75 than that of the substrate (1.08). The wear rates of the substrate and the coating are 0.295 mg/min and 0.103 mg/min, respectively, indicating the coating exhibits excellent wear resistance. The wear mechanism transforms severe adhesive wear and abrasive wear of the substrate to slight abrasive wear of the coating. The results can provide technical support to improve the properties of the Fe-based laser cladded coating. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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17 pages, 5094 KiB

Open AccessArticle

Comparative Analysis of Laser and Plasma Surfacing by Nickel-Based Superalloy of Heat Resistant Steel

by Artur Czupryński and Bernard Wyględacz

Materials 2020, 13(10), 2367; https://doi.org/10.3390/ma13102367 - 21 May 2020

Cited by 10 | Viewed by 2478

Abstract

In this article, the results of surfacing technology development, and structural, and mechanical properties examinations of 16Mo3 steel pipes with an outside coating of Inconel 625 deposited by automated plasma powder transferred arc (PPTA) and automated high power direct diode laser (HPDDL) surfacing [...] Read more.

In this article, the results of surfacing technology development, and structural, and mechanical properties examinations of 16Mo3 steel pipes with an outside coating of Inconel 625 deposited by automated plasma powder transferred arc (PPTA) and automated high power direct diode laser (HPDDL) surfacing were presented. Based on the results of non-destructive, metallographical macro- and microscopic, chemical composition, and thickness and hardness examinations optimal technology for use in high temperature energy or chemical industry applications was selected. The examinations conducted for each of the aforementioned technologies revealed the proper structure and high quality of coating. Dendritic structure with primary crystals growing in the direction of heat dissipation was revealed. No defects such as cracks, lack of fusion or porosity were found. Iron content in the most outer area of the layer made by PPTA with a heat input of 277–514 J/mm, thickness from 1.2 to 1.7 mm, between 4% and 5.5% was observed. Iron content in the most outer area of the layer made by HPDDL surfacing with output power of 1000–1600 W and scanning speed 3.3–4.7mm/s, from 0.6 to 1.3 mm in thickness, between 5.1% and 7.5% was observed. In coated pipes made by either technology high quality of surfaced layers, conforming to requirements posed on protective layers manufactured for prolonged exploitation in temperatures up to 625 °C, were observed. High temperature resistance examinations are the focus of further, yet unpublished, research. The obtained results point to slight differences in the parameters and properties of nickel-based superalloy layers surfaced on 16Mo3 pipes based on the technologies used. However, the process parameters optimization in the case of PPTA was simpler compared to HPDDL surfacing. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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18 pages, 10430 KiB

Open AccessArticle

Steel Sheets Laser Lap Joint Welding—Process Analysis

by Hubert Danielewski and Andrzej Skrzypczyk

Materials 2020, 13(10), 2258; https://doi.org/10.3390/ma13102258 - 14 May 2020

Cited by 15 | Viewed by 4066

Abstract

This article presents the results of steel-sheet lap-joint-welding using laser beam radiation. The use of a laser beam and keyhole effect for deep material penetration in lap joint welding was presented. Thermodynamic mechanism of laser welding is related to material properties and process [...] Read more.

This article presents the results of steel-sheet lap-joint-welding using laser beam radiation. The use of a laser beam and keyhole effect for deep material penetration in lap joint welding was presented. Thermodynamic mechanism of laser welding is related to material properties and process parameters. Estimation of welding parameters and joint properties’ analysis was performed through numerical simulation. The article presents a possibility of modeling laser lap-joint welding by using Simufact Welding software based on Marc solver and thermo-mechanical solution. Numerical calculation was performed for surface and conical volumetric heat sources simulating laser absorption and keyhole effect during steel sheet welding. Thermo-mechanical results of fusion zone (FZ), heat-affected zone (HAZ) and phase transformations calculated in numerical simulation were analyzed. The welding parameters for partial sealed joint penetration dedicated for gas piping installations were estimated from the numerical analysis. Low-carbon constructional steel was used for numerical and experimental analyses. A trial joint based on the estimated parameters was prepared by using a CO₂ laser. Numerical and experimental results in the form of hardness distributions and weld geometry were compared. Metallographic analysis of the obtained weld was presented, including crystallographic structures and inclusions in the cross section of the joint. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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20 pages, 9845 KiB

Open AccessArticle

Assessment of the Effect of Laser Welding on the Properties and Structure of TMCP Steel Butt Joints

by Jacek Górka

Materials 2020, 13(6), 1312; https://doi.org/10.3390/ma13061312 - 13 Mar 2020

Cited by 11 | Viewed by 2592

Abstract

The research work and related tests aimed to identify the effect of filler metal-free laser beam welding on the structure and properties of butt joints made of steel 700MC subjected to the TMCP (thermo-mechanically controlled processed) process. The tests involved 10-mm thick welded [...] Read more.

The research work and related tests aimed to identify the effect of filler metal-free laser beam welding on the structure and properties of butt joints made of steel 700MC subjected to the TMCP (thermo-mechanically controlled processed) process. The tests involved 10-mm thick welded joints and a welding linear energy of 4 kJ/mm and 5 kJ/mm. The inert gas shielded welding process was performed in the flat position (PA) and horizontal position (PC). Non-destructive testing enabled classification of the tested welded joints as representing the quality level B in accordance with the requirements set out in standard 13919-1. Destructive tests revealed that the tensile strength of the joints was 5% lower than S700MC steel. The results of tensile tests and changes in structure were referred to joints made using the MAG (Metal Active Gas) method. The tests of thin films performed using a high-resolution scanning transmission electron microscope revealed that, during laser beam welding, an increase in dilution was accompanied by an increase in the content of alloying microadditions titanium and niobium, particularly in the fusion area. A significant content of hardening phases in the welded joint during cooling led to significant precipitation hardening by fine-dispersive (Ti,Nb)(C,N) type precipitates being of several nanometres in size, which, in turn, resulted in the reduction of plastic properties. An increase in the concentration of elements responsible for steel hardening, i.e., Ti and Nb, also contributed to reducing the weld toughness below the acceptable value, which amounts to 25 J/cm². In cases of S700MC, the analysis of the phase transformation of austenite exposed to welding thermal cycles and the value of carbon equivalent cannot be the only factors taken into consideration when assessing weldability. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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19 pages, 12810 KiB

Open AccessArticle

Computational Techniques in Numerical Simulations of Arc and Laser Welding Processes

by Tomasz Kik

Materials 2020, 13(3), 608; https://doi.org/10.3390/ma13030608 - 29 Jan 2020

Cited by 40 | Viewed by 4884

Abstract

The article presents a comparison of modern computational techniques used in numerical analyses of welding processes. The principles of the “transient” technique calculations with a moving heat source, the “macro-bead” (MBD) technique, with an imposed thermal cycle on a selected weld bead section [...] Read more.

The article presents a comparison of modern computational techniques used in numerical analyses of welding processes. The principles of the “transient” technique calculations with a moving heat source, the “macro-bead” (MBD) technique, with an imposed thermal cycle on a selected weld bead section and the “local–global” approach with shrinkage calculation technique were described. They can be used, depending on the variant chosen, both for individual, simple weld joints and those made of many beads or constructions containing dozens of welds and welded elements. Differences in the obtained results and time needed to perform calculations with four different calculation examples of single and multipass arc and laser beam welding processes were presented. The results of calculations of displacements and stresses distributions in the welded joints using various computational techniques were compared, as well as the calculation times with the described techniques. The numerical analyses in the SYSWELD software package have shown the differences between the described computational techniques, as well as an understanding of the benefits and disadvantages of using each of them. This knowledge allows preparing an efficient and fast optimization of the welding processes, often aimed at minimizing deformations in the first place, as well as detection of potential defects of both simple and complex welded structures. In general, the possibilities and flexibility of modern numerical calculation software have been presented. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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11 pages, 6359 KiB

Open AccessArticle

Laser Surface Modification of Aluminium Alloy AlMg9 with B₄C Powder

by Marek Sroka, Ewa Jonda and Wojciech Pakieła

Materials 2020, 13(2), 402; https://doi.org/10.3390/ma13020402 - 15 Jan 2020

Cited by 10 | Viewed by 2252

Abstract

This paper presents the effects of laser treatment (fiber laser YLS-4000) on the microstructure and selected mechanical properties of the surface layer of AlMg (AlMg9) foundry alloy obtained by alloying with boron carbide (B₄C). The correlation between laser alloying process parameters [...] Read more.

This paper presents the effects of laser treatment (fiber laser YLS-4000) on the microstructure and selected mechanical properties of the surface layer of AlMg (AlMg9) foundry alloy obtained by alloying with boron carbide (B₄C). The correlation between laser alloying process parameters and selected properties of the formed layer was discussed. The studies were supported by microstructural analysis of the remelted zone (RZ), heat affected zone (HAZ), undissolved carbide particles, substrate material, and precipitates formed during rapid solidification. Metallographic investigations of the laser-treated layer were performed using optical microscopy and scanning electron microscopy (SEM). The elemental composition and a detailed analysis of chemical composition in micro-areas were carried out using energy dispersive X-ray spectroscopy (EDS). The remelting thickness, heat-affected zone (HAZ), and amount of base material in surface layers were determined. Microhardness tests were performed on transverse cross-sections of the remelted zone to obtain the hardness profiles in the base material (BM), remelted zone (RZ), and heat affected zone (HAZ). The hardness, roughness, and wear resistance measurements showed that the highest tribological properties of the obtained surface layer were achieved using 0.5 Bar protective gas (Ar) during alloying with B₄C powder. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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13 pages, 3349 KiB

Open AccessArticle

Quantitative Correlation between Thermal Cycling and the Microstructures of X100 Pipeline Steel Laser-Welded Joints

by Gang Wang, Jinzhao Wang, Limeng Yin, Huiqin Hu and Zongxiang Yao

Materials 2020, 13(1), 121; https://doi.org/10.3390/ma13010121 - 26 Dec 2019

Cited by 14 | Viewed by 3015

Abstract

Due to the limitations of the energy density and penetration ability of arc welding technology for long-distance pipelines, the deterioration of the microstructures in the coarse-grained heat-affected zone (HAZ) in welded joints in large-diameter, thick-walled pipeline steel leads to insufficient strength and toughness [...] Read more.

Due to the limitations of the energy density and penetration ability of arc welding technology for long-distance pipelines, the deterioration of the microstructures in the coarse-grained heat-affected zone (HAZ) in welded joints in large-diameter, thick-walled pipeline steel leads to insufficient strength and toughness in these joints, which strongly affect the service reliability and durability of oil and gas pipelines. Therefore, high-energy-beam welding is introduced for pipeline steel welding to reduce pipeline construction costs and improve the efficiency and safety of oil and gas transportation. In the present work, two pieces of X100 pipeline steel plates with thicknesses of 12.8 mm were welded by a high-power robot laser-welding platform. The quantitative correlation between thermal cycling and the microstructure of the welded joint was studied using numerical simulation of the welding temperature field, optical microscopy (OM), and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results show that the heat-source model of a Gaussian-distributed rotating body and the austenitization degree parameters are highly accurate in simulating the welding temperature field and characterizing the austenitization degree. The effects of austenitization are more significant than those of the cooling rate on the final microstructures of the laser-welded joint. The microstructure of the X100 pipeline steel in the HAZ is mainly composed of acicular ferrite (AF), granular bainite (GB), and bainitic ferrite (BF). However, small amounts of lath martensite (LM), upper bainite (UB), and the bulk microstructure are found in the columnar zone of the weld. The aim of this paper is to provide scientific guidance and a reference for the simulation of the temperature field during high-energy-beam laser welding and to study and formulate the laser-welding process for X100 pipeline steel. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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18 pages, 7149 KiB

Open AccessArticle

Flame Spraying of Aluminum Coatings Reinforced with Particles of Carbonaceous Materials as an Alternative for Laser Cladding Technologies

by Artur Czupryński

Materials 2019, 12(21), 3467; https://doi.org/10.3390/ma12213467 - 23 Oct 2019

Cited by 21 | Viewed by 3113

Abstract

The article presents results of the preliminary research of mechanical properties of flame-sprayed aluminum coatings reinforced with carbon materials made on the construction steel S235J0 substrate. For reinforcement the following carbon materials were used: carbon nanotubes Nanocyl NC 7000 (0.5 wt.% and 1 [...] Read more.

The article presents results of the preliminary research of mechanical properties of flame-sprayed aluminum coatings reinforced with carbon materials made on the construction steel S235J0 substrate. For reinforcement the following carbon materials were used: carbon nanotubes Nanocyl NC 7000 (0.5 wt.% and 1 wt.%) and carburite (0.5 wt.%). The properties evaluation was made using metallographic macroscope and microscope, chemical composition, microhardness, abrasion and erosion resistance studies. The obtained results were compared with aluminum powder coatings (EN AW 1000 series). It was proved that the flame spraying of aluminum coatings reinforced with particles of carbonaceous materials can be an effective alternative for laser cladding technology. The preliminary test results will be successively extended by further experiments to contribute in the near future to develop innovative technologies, that can be implemented in the automotive industry for production of components with high strength, wear resistance, good thermal conductivity and low density, such as brake shoes, cylinder liners, piston rings and gears. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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10 pages, 3671 KiB

Open AccessArticle

Role of Bead Sequence in Underwater Welding

by Jacek Tomków, Dariusz Fydrych and Grzegorz Rogalski

Materials 2019, 12(20), 3372; https://doi.org/10.3390/ma12203372 - 16 Oct 2019

Cited by 39 | Viewed by 4215

Abstract

This paper presents examinations of the role of the bead sequence in underwater welding. Two specimens of wet welded layers made by covered electrodes with the use of normalized S355G10+N steel were welded by a reasonable bead sequence. For each specimen, metallographic macro- [...] Read more.

This paper presents examinations of the role of the bead sequence in underwater welding. Two specimens of wet welded layers made by covered electrodes with the use of normalized S355G10+N steel were welded by a reasonable bead sequence. For each specimen, metallographic macro- and micro-scopic tests were done. Then, Vickers HV10 hardness measurements were conducted for each pad weld in the welded layer. The results show that welding in the water environment carries many problems in the stability of the welding arc, which influences the properties of the welds. The effects of refining and tempering the structure in heat-affected zones of earlier laid beads was observed, which provides a reduction of hardness. The possibility of applying two techniques while welding the layer by the wet method is described. It is stated that a reasonable bead sequence can decrease the hardness in heat-affected zones up to 40 HV10. Tempering by heat from next beads can also change the microstructure in this area by tempering martensite and can decrease susceptibility to cold cracking. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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14 pages, 5424 KiB

Open AccessArticle

Study of Optical Properties of Surface Layers Produced by Laser Surface Melting and Laser Surface Nitriding of Titanium Alloy

by Aleksander Lisiecki

Materials 2019, 12(19), 3112; https://doi.org/10.3390/ma12193112 - 24 Sep 2019

Cited by 22 | Viewed by 2783

Abstract

This study measured optical properties, such as specular, diffuse, and total reflection for 808 nm wavelength, characteristic for high power diode lasers radiation, from the surface of titanium alloy Ti6Al4V at delivery conditions, polished, and oxidized. Moreover, the optical properties of surface layers [...] Read more.

This study measured optical properties, such as specular, diffuse, and total reflection for 808 nm wavelength, characteristic for high power diode lasers radiation, from the surface of titanium alloy Ti6Al4V at delivery conditions, polished, and oxidized. Moreover, the optical properties of surface layers produced by high power direct diode laser (HPDDL) melting and nitriding were determined. Additionally, a methodology for determining the value of absorption for 808 nm wavelength of the HPDDL radiation on the surface of a melt pool during laser surface melting and nitriding of titanium alloy was proposed. The results show that the distinct differences in absorption affect the heat transfer, thermal conditions of laser heating and thereby the penetration depth during laser melting and nitriding of the titanium alloy. Full article

(This article belongs to the Special Issue Development of Laser Welding and Surface Treatment of Metals)

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