Article
Automation & Control Systems
Ivan Bunaziv, Cato Dorum, Steen Erik Nielsen, Pasi Suikkanen, Xiaobo Ren, Bard Nyhus, Magnus Eriksson, Odd M. Akselsen
Summary: The study focuses on the application of single-pass laser beam welding for steel components with wall thickness > 10 mm, investigating the causes and solutions of root humping. Experimental results show successful welding of different thickness plates under various process parameters, achieving good root quality by using a small air gap.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Chemistry, Physical
Vishwa Bhanu, Dariusz Fydrych, Ankur Gupta, Chandan Pandey
Summary: This investigation explores the weld characteristics of a laser welded dissimilar joint of ferritic/martensitic 9Cr-1Mo-V-Nb (P91) steel and Incoloy 800HT austenitic nickel alloy, revealing challenges such as susceptibility to solidification cracking during the welding process.
Article
Materials Science, Multidisciplinary
Meng Jiang, Nan Jiang, Xi Chen, Shengchong Ma, Yuan Chen, Yanbin Chen, Zhenglong Lei
Summary: This study investigated the process of laser welding under reduced ambient pressure to achieve a single-pass complete-joint-penetration weld of 20 mm-thick high-strength steel. Through experimental and theoretical approaches, a defect-free sound weld joint stronger than the base metal was obtained. The modeling results showed lower peak temperature and thinner liquid weld metal around keyhole under reduced ambient pressure, indicating the validity of the potential causative variables considered in the simulations.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Review
Optics
Yuantai Li, Shaoning Geng, Leshi Shu, Yan Li, Ping Jiang
Summary: Thick-section steel is widely used in large structural applications due to its high strength, good toughness, and low cost. Ultra-high-power laser welding (UHPLW) offers a new approach for manufacturing large thick-section steel structures by providing deep penetration. However, UHPLW of thick-section steel faces welding defects and challenges related to microstructure and mechanical properties. This review aims to introduce UHPLW technology, discuss defects prevention methods, and address the impact of microstructure on mechanical properties, providing future research perspectives for high-quality welded joints of thick-section steel.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Vitor E. C. Sousa, Francisco J. G. Silva, Antonio P. Pinho, Antonio B. Pereira, Olga C. Paiva
Summary: This study introduces four new heat treatment conditions for welding joints on P91 steel, aiming to reduce processing time, energy consumption, and achieve a better balance between mechanical strength and elongation after failure. These solutions result in a loss of approximately 14% in Ultimate Tensile Strength (UTS) compared to unwelded joints, but a gain of about 50% in elongation. Compared to the recommended solution in the codes, there is a decrease of 10% in UTS and an increase of 30% in elongation, saving significant time and energy in the treatment process.
Article
Engineering, Multidisciplinary
Hongju Fan, Peng Liu, Xinfang Guo, Xibao Wang, Yongbin Wang
Summary: This paper studies the welding performance of a novel heat-resistant steel tube, and the results show that the microstructure and mechanical characteristics of the welded joint are satisfactory. The hardness distribution demonstrates a low to high trend, and the joint exhibits good toughness and corrosion resistance.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2023)
Article
Materials Science, Multidisciplinary
Michael Rethmeier, Andrey Gumenyuk, Marcel Bachmann
Summary: The addition of oscillating and permanent magnetic fields to laser beam and laser-arc hybrid welding can bring beneficial effects, such as supporting weld pool contactlessly for thick metals and enhancing mixing of filler material for homogeneous mechanical properties. Recent research studies have demonstrated the applicability of this technique to various metal types, thicknesses, and welding conditions. The observations were backed by experimental studies and a deep understanding of the underlying physical mechanisms was obtained through numerical calculations.
SCIENCE AND TECHNOLOGY OF WELDING AND JOINING
(2022)
Review
Materials Science, Multidisciplinary
Eva S. Marques, Antonio B. Pereira, Francisco J. G. Silva
Summary: In order to reduce waste and undesirable costs, it is important to establish quality plans that ensure product conformity and address the root causes of welding defects. This study focused on dual phase (DP) steels, which are commonly used in the automotive industry, and developed a quality plan for laser welding DP steel components. The quality plan includes pre-welding, during and post-welding stages, and the mechanical properties of the welded components were also assessed. The findings suggest that DP steel has good weldability except for the softening of the heat affected zone (HAZ) and the growth of martensite in the fusion zone (FZ), and analysis techniques such as finite element method (FEM), visual techniques during welding, and digital image correlation (DIC) for post-weld analysis can help prevent failures.
Article
Metallurgy & Metallurgical Engineering
Michal Junek, Marie Svobodova, Jakub Horvath, Vladimir Mara
Summary: This study focuses on the analysis of microstructure degradation and mechanical property degradation of P91 and P92 steels in orbital narrow-gap welding. It reveals that using orbital narrow-gap tungsten inert gas welding technology can improve welding efficiency and repeatability.
STEEL RESEARCH INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Zhiwei Wang, Min Zhang, Cong Li, Fenglei Niu, Hao Zhang, Peng Xue, Dingrui Ni, Bolv Xiao, Zongyi Ma
Summary: In this study, the reliable welding of T91 heat-resistant steel to 316L stainless steel was improved through friction stir welding, resulting in a defect-free joint with a large bonding interface. The joint exhibited both mechanical mixing and metallurgical bonding at the bonding interface, and the material was renovated in the weld zone, leading to a high-strength welded joint comparable to the parent metal.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2023)
Article
Multidisciplinary Sciences
S. Rakesh, S. Raghuraman, R. Venkatraman
Summary: In this experiment, the fiber laser parameters were optimized for welding P91 steel, and the optimal solution was achieved. The results showed that welding speed had the most decisive influence on the welding effect, while laser power had significant influence on some welding characteristics. The obtained welding results were highly correlated with the expected values.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Hong-ju Fan, Peng Liu, Yong-bin Wang, Xin-fang Guo
Summary: In this study, gas tungsten arc welding (GTAW) + shielded metal arc welding (SMAW) were used to successfully weld G115 steel, which is a novel thick grade of heat-resistant steel. After post-weld heat treatment (PWHT), the weld zone (WZ) was composed of martensite and ferrite, with the precipitate M23C6. The average hardness of WZ was 273.1 HV, and the average impact toughness was above 39J, which met the requirements for actual production applications.
PHILOSOPHICAL MAGAZINE LETTERS
(2023)
Article
Optics
Manpeng Wu, Zhen Luo, Sansan Ao
Summary: This paper presents a novel welding method for extra-thick high-strength steel, involving double-sided narrow gap oscillating laser autogenous backing welding and oscillating laser-TIG hybrid filling welding. The performance of penetration and formation of the backing welding and fusion and formation of the filling welding were studied under different process parameters. Under the optimal conditions, sound and symmetric welded joints were achieved for 80 mm thick SA-738Gr.B steel in the horizontal position. The microstructure and mechanical properties of the welded joints were analyzed, showing fine equiaxed grains in the weld metal and heat-affected zone. The mechanical properties of the welded joint met the design requirements, indicating sufficient strength and toughness.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
Jiecai Feng, Liqun Li, Yanbin Chen, Yingzhong Tian, Yongle Sun, Xuanjun Zhang, Jie Zhang
Summary: The study investigated the inhomogeneous microstructure and fatigue crack propagation of a 30 mm thick-section high strength steel welded joint using double-sided hybrid fiber laser-arc welding. The results showed that the laser zone had smaller grain size, higher dislocation density, and higher fatigue crack propagation resistance compared to the arc zone.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Chemistry, Physical
Jiri Capek, Karel Trojan, Jan Kec, Ivo Cerny, Nikolaj Ganev, Stanislav Nemecek
Summary: The study focuses on the feasibility and advantages of using laser welding technology for pipeline production. Through mechanical tests and microstructural analysis, the potential application of laser welding for high-pressure pipelines is highlighted.
Article
Metallurgy & Metallurgical Engineering
K. K. Ray, S. Tiwari, Hemlata Kumari, Mamta Kumari, Hemant Kumar, S. K. Albert, A. K. Bhaduri
TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS
(2016)
Article
Materials Science, Multidisciplinary
Hemant Kumar, V. Ramakrishnan, S. K. Albert, A. K. Bhaduri, K. K. Ray
JOURNAL OF NUCLEAR MATERIALS
(2017)
Article
Materials Science, Multidisciplinary
Hemant Kumar, V. Ramakrishnan, S. K. Albert, A. K. Bhaduri, K. K. Ray
JOURNAL OF NUCLEAR MATERIALS
(2017)
Article
Nuclear Science & Technology
Hemant Kumar, K. V. Phani Prabhakar, Shiju Sam, S. K. Albert, G. Padmanabham, A. K. Bhaduri, T. Jayakumar, E. Rajendra Kumar
FUSION SCIENCE AND TECHNOLOGY
(2014)
Article
Materials Science, Multidisciplinary
S. Gnanasekaran, G. Padmanaban, V Balasubramanian, Hemant Kumar, Shaju K. Albert
HIGH TEMPERATURE MATERIALS AND PROCESSES
(2019)
Article
Engineering, Mechanical
Rismaya Kumar Mishra, Hemant Kumar, G. A. Harmain, S. K. Albert
Summary: Nickel-based thick hardface coatings are widely used in nuclear power plants due to their superior wear and high-temperature resistance properties. This study aimed to investigate the wear behavior of Ni-Cr-B-Si hardface coating deposited on 316LN stainless steel using the Cold Metal Transfer (CMT) welding process, revealing optimal hardness and wear resistance. The experiment found that CMT can be utilized to deposit crack-free, low dilution, and wear-resistant hardface coatings in nuclear industries.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Mechanical
Shaju K. Albert, R. Suresh Kumar, Hemant Kumar, R. Nanda Kumar, Anita Toppo, A. Poonguzhali, M. Elango, A. Babu
Summary: The root cause of the failure of the orifice assembly was identified as stress corrosion cracking (SCC), which was due to residual tensile stresses developed during welding. The design of the orifice assembly has been revised based on the insights gained from the failure analysis to prevent similar failures in the future. Austenitic stainless steels are highly susceptible to SCC under the combined action of tensile stress and favorable environmental conditions, leading to slow crack propagation until the stresses exceed the fracture strength.
ENGINEERING FAILURE ANALYSIS
(2021)
Article
Materials Science, Multidisciplinary
Arnab Sarkar, Soudip Basu, Amulya Bihari Pattnaik, Balila Nagamani Jaya, Shyamprasad Karagadde, Indradev Samajdar, Hemant Kumar, Ravi Kumar, R. Mythili, Chanchal Ghosh, Arup Dasgupta, Shaju Albert
Summary: Micro-fissures were found in laser-welded stainless steel weldments, with their relative presence decreasing with increasing weld heat input. The spatial locations and relative presence of the micro-fissures were associated with local misorientations and grain reference orientation deviation. Solidification shrinkage was identified as the origin of the micro-fissures in laser welds. Sub-size tensile specimens with digital image correlation revealed that the presence of micro-fissures was related to mechanical property degradation.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Rismaya Kumar Mishra, Hemant Kumar, G. A. Harmain, Shaju K. Albert
Summary: Ni-Cr-B-Si hardface coating plays a crucial role in nuclear power plants. In this study, a crack-free coating with superior wear behavior was successfully developed using the CMT process, providing higher hardness and lower wear rate compared to the coating made by the PTA process.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART L-JOURNAL OF MATERIALS-DESIGN AND APPLICATIONS
(2023)
Article
Thermodynamics
Ojas Satbhai, Suruj Protim Neog, Shyamprasad Karagadde, Indradev Samajdar, Balila Nagamani Jaya, Hemant Kumar, R. Ravikumar, R. Mythili, Chanchal Ghosh, Arup Dasgupta
Summary: This study presents generalised predictive approaches for the prevention of solidification cracks in critical engineering applications. It first uses high-fidelity CFD simulations to compute transient temperature and flow fields in pulsed laser welding, and verifies the temperature field by comparing experimental and numerical weld profiles. Then, it proposes a novel macro-scale computational methodology for in situ numerical estimation of the Crack Vulnerable Index (CVI) based on thermal characteristics. The predictions agree well with experimental findings, indicating that the heat-flow direction is closely related to crack orientations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Materials Science, Multidisciplinary
Hemant Kumar, Rismaya Kumar Mishra, Ghulam Ashraf Ul Harmain
Summary: The selection of tribopairs is crucial in controlling material loss under rubbing conditions. This study investigates the wear behavior of a Ni-based hardfaced coating on 316LN stainless steel under similar and dissimilar mating conditions. The results show that the wear rate for dissimilar mating conditions is one order of magnitude higher than that for similar mating conditions, and adhesive wear is the dominant wear mechanism in both conditions. This study suggests that similar material combinations should be preferred in the design of tribopairs to avoid significant material losses.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART L-JOURNAL OF MATERIALS-DESIGN AND APPLICATIONS
(2023)
Article
Engineering, Mechanical
Vani Shankar, Hemant Kumar, R. Kannan, C. R. Das, A. Nagesha, V. Karthik, A. Moitra, M. Vasudevan
Summary: The aim of this study is to investigate the behavior of low cycle fatigue (LCF) and creep-fatigue interaction (CFI) in two product forms of Alloy 625. The results showed that the materials produced using additive manufacturing process have better fatigue life compared to those produced by conventional casting. Microstructural analysis revealed the generation of alternating strain within the microstructure and the occurrence of strain incompatibility in the partitioned regions of fine and neighboring coarser grains. At higher temperatures, additional phenomena such as dynamic strain ageing, oxidation, and creep led to earlier fatigue failure.
INTERNATIONAL JOURNAL OF FATIGUE
(2024)
Proceedings Paper
Engineering, Mechanical
Sudheer Patri, Hemant Kumar, K. Krishna Prasad, C. Meikandamurthy, B. K. Sreedhar, R. Vijayashree, V. Prakash, P. Selvaraj
2ND INTERNATIONAL CONFERENCE ON STRUCTURAL INTEGRITY AND EXHIBITION 2018 (SICE 2018)
(2019)
Article
Materials Science, Multidisciplinary
S. Gnanasekaran, G. Padmanaban, V. Balasubramanian, H. Kumar, S. K. Albert
LASERS IN ENGINEERING
(2019)
Proceedings Paper
Engineering, Mechanical
Rakesh K. Rajan, Hemant Kumar, S. K. Albert, T. R. Vijayaram
DYNAMICS OF MACHINES AND MECHANISMS, INDUSTRIAL RESEARCH
(2014)
