Browsing by Author "John, M."

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A study on HAZ behaviour in 800 MPa cold rolled and hot rolled steel weld
(Elsevier Ltd, 2021) John, M.; Perka, P.; Udaya Bhat, K.; Bhat Panemangalore, D.
In the automotive sector, the demand for advanced high strength steels (AHSS) is increasing day by day. Based on the application, cold rolled and hot rolled steels are used for various components in a vehicle body. Typically, cold-rolled grades with dual-phase, DP780 steel is used in the form of welded blanks. Hot rolled grades with Ti-Nb microalloy content, like HS800 steel are used in as long members. Welding is an important step to be considered in the design of materials for mass production as required in the automobile sector. In this investigation, Pulsed Gas Metal Arc Welding (P-GMAW) is carried out on both steels with a solid filler wire of strength 800 MPa. Static tensile tests indicated that failure in both steels welds occurred in the heat-affected zone region. The crack initiation and propagation behaviour were compared in both steels. In DP780 steels, the presence of the acicular ferrite and acicular martensite resisted the crack initiation and propagation in the weld region whereas, the chaotic nature of the acicular ferrite in HS800 steel. Microstructural studies revealed that the reason for heat affected zone (HAZ) failure in HS800 steel is due to the presence of hard TiN particles with a size of more than 1 Âµm which causes decohesion in the matrix. In DP780 steel failure is due to the presence of tempered martensite in the subcritical heat affected zone (SCHAZ). This study divulges the influence of filler wire chemistry, dilution, and welding parameters on cold rolled and hot rolled AHSS steels used in the automotive industry. Â© 2021 Elsevier Ltd. All rights reserved.
Advanced High-Strength Steels for Automotive Applications: Arc and Laser Welding Process, Properties, and Challenges
(MDPI, 2022) Perka, A.K.; John, M.; Kuruveri, U.B.; L Menezes, P.L.
In recent years, the demand for advanced high-strength steel (AHSS) has increased to improve the durability and service life of steel structures. The development of these steels involves innovative processing technologies and steel alloy design concepts. Joining these steels is predominantly conducted by following fusion welding techniques, such as gas metal arc welding, tungsten inert gas welding, and laser welding. These fusion welding techniques often lead to a loss of mechanical properties due to the weld thermal cycles in the heat-affected zone (HAZ) and the deposited filler wire chemistry. This review paper elucidates the current studies on the state-of-the-art of weldability on AHSS, with ultimate strength levels above 800 MPa. The effects of alloy designs on the HAZ softening, microstructure evolution, and the mechanical properties of the weld joints corresponding to different welding techniques and filler wire chemistry are discussed. More specifically, the fusion welding techniques used for the welding of AHSS were summarized. This review article gives an insight into the issues while selecting a particular fusion welding technique for the welding of AHSS. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
AHSS welding using undermatching filler wires and process advantages with P-GMAW
(Elsevier Ltd, 2021) John, M.; Perka, P.; Udaya Bhat, K.
The major challenge during welding of advanced high strength steels (AHSS) is finding an appropriate low cost filler wire which minimizes the softening in the heat affected zone (HAZ). The fabricators always prefer undermatching wires to join the thinner sections. This study reports the differences in the microstructure and mechanical properties of Ti-Nb microalloyed steel prior welded using pulse gas metal arc welding (P-GMAW) and standard gas metal arc welding (GMAW). The results indicate that the microalloyed steel welded using P-GMAW has inherent advantage over the standard GMAW. The pulses intensified the vibration perturbation in the weld puddle which cause microstructural refining and increased formation of the acicular ferrite (AF) constituent. The higher percentage of AF present in the weldment resisted propagation of the crack during static tensile test. Microhardness, ultimate tensile strength and joint efficiency during P-GMAW are much higher than the samples welded by standard GMAW. Â© 2021 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the Global Conference on Recent Advances in Sustainable Materials 2021.
Effect of employing metal cored filler wire for single v butt joint welding of Ti-Nb microalloyed 800MPa steels
(American Institute of Physics Inc. subs@aip.org, 2020) John, M.; Peraka, A.K.; Kuruveri, U.B.
Ti-Nbmicroalloyed 800 MPa steels are an important group of advanced high strength steels being developed for automobile applications. One requirement for practical application is the development of a reliable welding process. P-GMAW technique with synergic control and metallic cored filler wires are the advances in the domain of GMAW technique. These are used in welding Ti-Nb steel. The results indicate that use of metal cored wire increased penetration, reduces spatter marginally reduces HAZ width, increases weld hardness, and UTS is marginally higher. In both samples fracture took place in the HAZ, indicating it is the weakest domain in the welded system. Overall results indicate that the use of metal cored wire is beneficial compared to the solid wire during P-GMAW. Â© 2020 Author(s).
Effect of filler wire strength on high strength low alloy steels
(Elsevier Ltd, 2021) John, M.; Kumar, P.A.; Bhat, K.U.
Fusion welding of Ti-Nb microalloyed steels often leads to softening in the heat affected zone (HAZ) due to weld thermal cycles. Apart from heat input and width of HAZ, selection of filler wire also plays an important role, to achieve the minimum strength requirement of the parent material. Steel plates with 800 MPa ultimate tensile strength were butt welded using pulsed gas metal arc welding (P-GMAW) process, with undermatching, matching and overmatching strength filler wires. Welding parameters were selected in such a way that the heat input per unit weld length is almost constant. In all the samples, microstructural features were similar in the HAZ region. Static tensile tests indicated that failure in the samples welded using undermatching filler occurred at welded region, whereas the samples welded with matching and overmatching fillers failed at HAZ region. Further fracture studies indicated that, in case of under matching filler wire samples, crack propagates along the Widmanstatten ferrite present in the weld zone, whereas in other two samples, crack initiated at coarse TiN - matrix interface in the HAZ region. This study shows that overmatching fillers are recommended to overcome strength loss due to HAZ softening. Â© 2021 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of the scientific committee of the Global Conference on Recent Advances in Sustainable Materials 2021.
Effect of wire feed rate on microstructure development during bead on plate welding of microalloyed steel using P-GMAW
(Elsevier Ltd, 2020) John, M.; Kumar, P.A.; Udaya Bhat, K.
Welding of advanced high strength steel has been challenging because of difficulties associated with retaining high strength and toughness in the weldment. In this investigation, Ti-Nb microalloyed 800 MPa steel was subjected to bead on plate welding trials using ER70S-6 filler wire. Synergic pulsed mode was used for welding. Here the system could optimize the welding current and voltage once the selection of wire feed rate was done. Analysis of weld bead was done by measuring the weld bead parameters, observing microstructural details and calculating microhardness values. The investigation indicates that 6 m/min wire feed rate produces good weld bead, minimum reinforcement and optimum dilution. The microstructure is predominantly acicular in nature and microhardness in weld and HAZ is higher compared to the beads produced using other wire feed rates. Â© 2020 Elsevier Ltd. All rights reserved.
Laser Cladding-Based Surface Modification of Carbon Steel and High-Alloy Steel for Extreme Condition Applications
(MDPI, 2022) John, M.; Kuruveri, U.B.; L Menezes, P.L.
Laser cladding (LC) is a laser-based surface modification technique widely adopted to develop a thin coating or remanufacture worn-out mechanical components that work in extreme conditions. LC helps to generate superior surface properties and surface integrity on the substrate surface, improving the service life. This review paper provides a comprehensive overview of the LC process, different powder feeding methods, and the uniqueness of LC over other coating techniques. More specifically, the current state-of-the-art of the LC process on carbon steel and high-alloy steel-based mechanical components operating in diverse industries was elucidated. Furthermore, the effect of LC processes on mechanical properties such as wear, corrosion and fatigue properties are discussed. In addition, the LC process’s influence on microstructural features and microstructural modifications is explained. Finally, this study explores some potential applications of the LC process in diverse industries. © 2022 by the authors.
Surface Modification of 6xxx Series Aluminum Alloys
(MDPI, 2022) Kuruveri, U.B.; Bhat Panemangalore, P.; Kuruveri, S.B.; John, M.; L Menezes, P.L.
Due to their superior mechanical properties, formability, corrosion resistance, and lightweight nature, 6xxx series aluminum (Al) alloys are considered as a promising structural material. Nevertheless, the successful application of these materials depends on their response to the external environment. Recently, designers considered the surface properties an equally important aspect of the component design. Due to this concern, these alloys are subjected to varieties of surface modification methodologies. Many methodologies are explored to modify the 6xxx series Al alloys sur-faces effectively. These methods are anodizing, plasma electrolytic oxidation (PEO), cladding, friction stir processing, friction surfacing, melting, alloying, and resolidification using high energy beams, etc. This review work discusses some of these methods, recent research activities on them, important process variables, and their role on the final properties of the surfaces. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Tribological, Corrosion, and Microstructural Features of Laser-Shock-Peened Steels
(MDPI, 2023) John, M.; Ralls, A.M.; Kuruveri, U.B.; L Menezes, P.L.
The degradation due to high friction, wear, and corrosion of mechanical components for industrial applications has invoked substantial economic loss. In recent years, scientists and engineers have developed techniques to mitigate the issues associated with this deterioration potentially. Among these developed techniques, controlling the coefficient of friction (COF), wear rate, and corrosion using laser shock peening (LSP) is a preeminent and popular innovation. This paper aims to summarize the existing literature on the LSP of steels, discuss the current state-of-the-art LSP, and demonstrate the mechanisms that dictate the enhanced tribological and corrosion properties. More specifically, the influence of LSP on COF, wear rate, corrosion potential, surface hardening, and surface morphological changes on various materials used for aerospace, automotive, biomedical, nuclear, and chemical applications is explained. In addition, grain refinement and the gradient microstructure formation during LSP are discussed. Additionally, recent advances and applications of LSP are elucidated. © 2023 by the authors.
Ultrasonic Nanocrystal Surface Modification: Processes, Characterization, Properties, and Applications
(MDPI, 2022) Thazhathidathil, A.; John, M.; Ralls, A.M.; Antony Jose, S.A.; Kuruveri, U.B.; L Menezes, P.L.
Ultrasonic nanocrystal surface modification (UNSM) is a unique, mechanical, impact-based surface severe plastic deformation (S2PD) method. This newly developed technique finds diverse applications in the aerospace, automotive, nuclear, biomedical, and chemical industries. The severe plastic deformation (SPD) during UNSM can generate gradient nanostructured surface (GNS) layers with remarkable mechanical properties. This review paper elucidates the current state-of-the-art UNSM technique on a broad range of engineering materials. This review also summarizes the effect of UNSM on different mechanical properties, such as fatigue, wear, and corrosion resistance. Furthermore, the effect of USNM on microstructure development and grain refinement is discussed. Finally, this study explores the applications of the UNSM process. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Ultrasonic surface rolling process: Properties, characterization, and applications
(MDPI, 2021) John, M.; Ralls, A.M.; Dooley, S.C.; Thazhathidathil, A.K.V.; Perka, A.K.; Kuruveri, U.B.; L Menezes, P.L.
Ultrasonic surface rolling process (USRP) is a novel surface severe plastic deformation (SPD) method that integrates ultrasonic impact peening (UIP) and deep rolling (DR) to enhance the surface integrity and surface mechanical properties of engineering materials. USRP can induce gradient nanostructured surface (GNS) layers on the substrate, providing superior mechanical properties, thus preventing premature material failure. Herein, a comprehensive overview of current-state-of-the art USRP is provided. More specifically, the effect of the USRP on a broad range of materials exclusively used for aerospace, automotive, nuclear, and chemical industries is explained. Furthermore, the effect of USRP on different mechanical properties, such as hardness, tensile, fatigue, wear resistance, residual stress, corrosion resistance, and surface roughness are summarized. In addition, the effect of USRP on grain refinement and the formation of gradient microstructure is discussed. Finally, this study elucidates the application and recent advances of the USRP process. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Welding Techniques for High Entropy Alloys: Processes, Properties, Characterization, and Challenges
(MDPI, 2022) John, M.; Diaz, O.; Esparza, A.; Fliegler, A.; Ocenosak, D.; van Dorn, C.; Udaya Bhat, K.; L Menezes, P.L.
High entropy alloys (HEAs) are the outstanding innovations in materials science and engineering in the early 21st century. HEAs consist of multiple elements with equiatomic or near equiatomic compositions, which exhibit superior mechanical properties, such as wear resistance, fatigue resistance, and corrosion resistance. HEAs are primarily used in structural and functional applications; hence, appropriate welding processes are essential to enhancing the performances and service lives of HEA components. Herein, a comprehensive overview of current state-of-art-of welding techniques for HEAs is elucidated. More specifically, the article discusses the fusion-based welding techniques, such as gas tungsten arc welding (GTAW) and laser beam welding (LBW), and solid-state welding techniques, such as friction stir welding (FSW) and explosive welding (EB), for a broad category of HEAs. In addition, the microstructural features and mechanical properties of HEAs welded using different techniques were explained for a broad spectrum of HEAs. Finally, this review discusses potential challenges in the welding of HEAs. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.