Informatics Publishing Limited

Tushar Sonar ¹, V. Balasubramanian ¹, S. Malarvizhi ¹, T. Venkateswaran ², D. Sivakumar ²

Affiliations
1 Centre for Material Joining and Research (CEMAJOR), Dept. of Mfg. Engg., Annamalai University, Annamalai Nagar, Tamilnadu, IN
2 Vikram Sarabhai Space Centre (VSSC), ISRO, Thiruvananthapuram, IN

Abstract

Inconel 718 is a nickel-based superalloy which is of potential interest in high temperature applications in rocket and gas turbines. This alloy is mostly joined by Gas Tungsten Arc Welding (GTAW) process for clean and precise welds and it is economical and shop friendly. However, due to the high heat input associated with this process, the joints are more prone for metallurgical problems such as coarse dendritic structure and segregation in weld metal region and liquation cracking in heat affected zone (HAZ) which significantly reduces the mechanical properties of the welded joints. To overcome these shortcomings, a recently developed Gas Tungsten Constricted Arc Welding (GTCAW) process is used for joining Inconel 718 alloy. It is the advanced variant of GTAW process with magnetic arc constriction achieved by introducing high frequency pulsing Current (known as Delta Current). Delta Current pulsing at a very high frequency is controlling factor for the rise and fall of magnetic arc constriction during welding. The main objective of this investigation is to make the potential use of Magnetic Arc Constriction to reduce the heat input for minimizing metallurgical problems and enhancing the mechanical properties of the joints. To achieve this, main effect of Delta Current on tensile properties and microstructural characteristics of Inconel 718 alloy is investigated.

Keywords

Gas Tungsten Constricted Arc Welding (GTCAW), Delta Current, Tensile Properties, Microstructural Characteristics.

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Tushar Sonar ¹, V. Balasubramanian ¹, S. Malarvizhi ¹, T. Venkateswaran ², D. Sivakumar ²

Affiliations
1 Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University , Annamalai Nagar 608002, Tamilnadu, IN
2 Vikram Sarabhai Space Centre (VSSC), ISRO, Thiruvananthapuram 695022, Kerala, IN

Abstract

Inconel 718 is a nickel-based superalloy mostly used in high temperature applications in aerospace sector due to its extensive mechanical properties and weldability . Gas T ungsten Arc Welding (GT AW) process is widely used for joining of Inconel 718 alloy for cleaner , precise and high-quality welds. However , due to the high heat input and wider arc associated with this process, it is having certain metallurgical problems in welding, such as coarse dendritic structure and segregation of alloying elements in weld metal region which significantly reduces the mechanical properties of the joints. T o overcome these limitations, a newly developed Gas T ungsten Constricted Arc Welding (GTCAW) process is employed to join Inconel 718 alloy . It is the advanced configuration of GTAW process, based on magnetic arc constriction induced by high frequency pulsing of the current known as Delta Current. The main objective of this investigation is to study the effect of Delta Current Frequency (DCF) on the weldability of Inconel 718 alloy for its viability in aerospace applications. The joints welded at 4 kHz showed superior tensile properties due to the refinement of grains in fusion zone. Increase in DCF results in decrease in tensile properties of the joints due to the coarsening of dendritic fusion zone microstructure. It is attributed to the stacking of heat input during welding.

Keywords

Gas Tungsten Constricted Arc Welding, GTCAW, Delta Current Frequency, Inconel 718, T Ensile Properties, Microstructure.

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Tushar Sonar ¹, V. Balasubramanian ², S. Malarvizhi ², Namita Dusane ³

Affiliations
1 G.S.Mandal's Maharashtra Institute of Technology,Aurangabad - 431010, Maharashtra State, IN
2 Centre for Materials Joining and Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University Annamalai Nagar - 608002, Tamil Nadu State, IN
3 Department of Computer Science and Applications, Hinduja College of Commerce Mumbai 400004, Maharashtra State, IN

Abstract

The IoT (Internet of Thing) basically pertains to the concept of linking anything that is powered both to the internet and each other and simulating human intelligence by machines, particularly computer systems is artificial intelligence. It includes learning (acquisition of data and rules for exploiting the data), logic (exploiting rules to arrive at probable or definitive findings) and selfrectification. Many automatic welding machines are now connected to a computer and are fully networked and can be reached anywhere in world from a computer at any time. The first apparent use would be in the evaluation and configuration of the equipment itself, as the equipment must be regularly interfaced with a network to perform these functions. Future IoT technology for the welding sector is likely to emerge largely as part of an artificial intelligence network, as it would be extremely beneficial to control and monitor functions even though the system is not in connection with internet. Simulating human intelligence by machines, specifically computers is known as Artificial intelligence (AI). It includes learning (acquisition of data and rules for exploiting the data), logic (exploiting rules to arrive at probable or definitive findings) and self-rectification. AI is incorporated into a variety of different types of technology. AI will have IoT flexibility which would play a major role in complying the requirements of Welding Industry 4.0.

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Tushar Sonar ¹, V. Balasubramanian ², S. Malarvizhi ², Namita Dusane ³, V. Sivamaran ⁴, C. Rajendran ⁵

Affiliations
1 G. S. Mandal's Maharashtra Institute of Technology, Aurangabad, Maharashtra, IN
2 Annamalai University, Annamalai Nagar, Tamil Nadu, IN
3 Hinduja College of Commerce, Mumbai, Maharashtra, IN
4 Audisankara College of Engineering & Technology (Autonomous), Gudur, Andhra Pradesh, IN
5 Sri Krishna College of Engineering and Technology, Coimbatore, Tamil Nadu, IN

Abstract

The objective of this paper is to explain about application of Internet of Things (IoT) and Artificial Intelligence (AI) in welding of Indian Railways. The introduction of welding technology has also been followed by the country’s economic growth. Indian Railways has long been the single most significant infrastructure entity in India, with the railway track network expanding for many years. The new manufacturing sector is speeding the transition to digital and intelligent manufacturing, with the ongoing growth and maturity of cloud computing, big data, IoT and other innovations. Welding methods are also one of the fields where AI is tested and used early, with the help of information technology. Train maintenance and repair is usually carried out in demanding working conditions and frequently under demand from time. In such high demand and dynamic activities, it helps to decrease human error. In the welding of rail tracks and machine parts, IoT and AI will certainly offer many advantages in less time and with greater accuracy and precision. It will allow the Indian Railways to become more profitable and effective.

Keywords

Indian Railways, Internet of Things, Artificial Intelligence, Welding 4.0.

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C. Rajarajan ¹, P. Sivaraj ², Tushar Sonar ³, S. Raja ⁴, N. Mathiazhagan ¹

Affiliations
1 Meenakshi Ramaswamy Engineering College, Thathanur, Tamil Nadu, IN
2 Annamalai University, Annamalai Nagar, Tamil Nadu, IN
3 G. S. Mandal's Maharashtra Institute of Technology, Aurangabad, Maharashtra, IN
4 Alagappa University, Karaikudi, Tamil Nadu, IN

Abstract

The joining of advanced high strength steel (AHSS) of type dual phase 800 (DP800) by fusion welding is challenging owing to its high strength and complex microstructural features. It leads to softening of heat affected zone (HAZ) and cracking due to the high heat input associated with fusion welding processes. This significantly deteriorates the tensile shear fracture properties of DP800 steel joints. To overcome this problem, resistance spot welding (RSW) is employed to join DP800 steel thin sheets. It involves resistive heating of joining surfaces under pressure at a temperature less than melting point of parent metal. This significantly reduces the issues in joining DP800 steel such as softening in HAZ, solidification and HAZ cracking and offers precise spot weld. The tensile shear fracture properties of joints are influenced by RSW parameters such as welding current, welding time, and electrode force. Hence, establishing empirical relationships to predict the tensile shear fracture properties of joints is crucial. So, the main objective of this investigation is to establish empirical relationships to predict the tensile shear fracture properties of resistance spot welded dual phase 800 steel lap joints using regression analysis. The optimal process window of RSW is established using response surface methodology (RSM) to attain superior tensile shear fracture properties of DP800 steel joints.

Keywords

Resistance Spot Welding, Advanced High Strength Steel, Tensile Shear Fracture Load, Microstructure, Nugget Hardness.

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P. Rajalingam ¹, S. Rajakumar ², V. Balasubramanian ², Tushar Sonar ³, S. Kavitha ⁴

Affiliations
1 4Centre for Materials Joining and Research (CEMAJOR), Annamalai University, Annamalai Nagar, Tamil Nadu, India., IN
2 Centre for Materials Joining and Research (CEMAJOR), Annamalai University, Annamalai Nagar, Tamil Nadu, India., IN
3 Centre for Welding and Additive Manufacturing (C-WAM), G. S. Mandal’s Maharashtra Institute of Technology, Aurangabad, Maharashtra, India., IN
4 Department of Electronics and Instrumentation Engineering, Annamalai University, Annamalai Nagar, Tamil Nadu, India., IN

Abstract

Resistance spot welding (RSW) is used to overcome the issues in fusion welding of DP-1000 steel such as softening in heat affected zone (HAZ), solidification cracking, high thermal residual stresses and distortion. The main objective of this investigation is to develop the empirical relationships to predict the tensile shear fracture load bearing capability of spot joints for automotive applications. The three factor – three level box-behnken design (3X3-BBD) consisting ofless experiments was chosen for developing the experimental matrix. The lap tensile shear fracture load (LAP-TSFL) and cross tensile shear fracture load (CROSS-TSFL) tests were performed to determine the load bearing capability of spot joints. The empirical relationships of LAP-TSFL and CROSS-TSFL of spot joints were developed using polynomial regression equations incorporating the process parameters in coded form. Analysis of Variance (ANOVA) was executed to check the viability of developed empirical relationships for LAP-TSFL and CROSS-TSFL. The empirical relationship accurately predicted the LAP-TSFL and CROSS-TSFL capability of spot joints with less than 1% error at 95% confidence level.

Keywords

DP-1000 Steel, Resistance Spot Welding, Optimization, Tensile Shear Fracture Load.

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C. Rajarajan ¹, Tushar Sonar ², P. Sivaraj ³, V. Balasubramanian ³

Affiliations
1 Meenakshi Ramaswamy Engineering College, Thathanur, Tamil Nadu, India, IN
2 G. S. Mandal’s Maharashtra Institute of Technology, Aurangabad, Maharashtra, India, IN
3 Centre for Materials Joining & Research (CEMAJOR), Annamalai University, Annamalai Nagar, Tamil Nadu, India, IN

Abstract

DP800 is an advanced high strength steel containing duplex microstructure of ferrite and martensite phases. It is broadly used in automotive structural frame applications owing to its high strength to weight ratio. DP steel is mainly joined by resistance spot welding (RSW) to avoid the problems of solidification cracking and severe HAZ softening. In this study, the effect of copper electrode pressure on nugget diameter and mechanical performance of resistance spot welded 1.2 mm thick DP800 steel sheets are investigated. The tensile shear strength (TSS) properties were evaluated in straight lap (SL-TSS) and cross lap (CL-TSS) joint configuration. Results showed that the DP-800 steel spot joints developed using the electrode pressure of 4.0 MPa exhibited superior SL-TSS of 830 MPa and CL-TSS of 684 MPa. It is attributed to the evolution of finer martensitic needles in nugget zone.

Keywords

Dual-Phase Steel, Resistance Spot Welding, Tensile Shear Strength, Microstructure, Electrode Pressure.

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