Indian Welding Journal

T. K. Pal

Abstract

The issue of IWJ comes to you with a new look. It shows Robotic MIG welding set up attached with fume chamber. Though it is now a very attractive welding process to the manufacturing industries globally, unfortunately none of the technical paper in this issue dealt with.

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T. K. Pal

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The evolution of recent technological advances in welding processes, equipment, consumables, automation and overall system integration has resulted in new directions of welding technology to satisfy the demands of fabrication industries. The National Welding Seminar (NWS 2015), which is to be held in the beginning of New Year 2015 at Jamshedpur during January 22-24, is expected to focus the trends in development of welding technology through keynote addresses and invited talks delivered by some of the most renowned experts from India and abroad. Also the exhibitions will provide the latest welding technologies by leading equipment and electrode manufactures. This will be a great opportunity for all HW-India members to get exposed to the new developments taken place at different aspects of welding technology over the years. We expect NWS 2015 to be a very grand success.

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T. K. Pal

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This volume of the journal has two technical papers. The first technical paper from A Murugan et al. discusses the predominant diffusion bonding parameters involved in joining bimetallic powder metallurgy product, and empirical relationship has been developed to predict the bond strength.

The effect of heat input on the Intergranular corrosion resistance of duplex stainless steel as clad material evaluated by double-loop electrochemical has been described in the second technical paper.

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T. K. Pal

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With the demand for stringent quality requirement of weld, the chemical and physical reactions occurring during welding are being researched. Various techniques are being applied to understand those reactions for improved weld performance. In their paper "Evaluation of arc welding process using digital storage oscilloscope and high speed camera" N. Savyasachi et al. have emphasized that probability density distribution (PDD) analysis of the voltage and current signals from digital storage oscilloscope (DSO) and a high speed camera with laser light illumination could evaluate the performance of consumables or power sources.

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T. K. Pal

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The Welding technology scenario in India will remain incomplete unless the activities of welding technology in Industries across the country is not highlighted. Since Indian Welding Journal (IWJ) is the only official journal published by IIW-India and highlights the activities prevailing in welding/joining, should reflect the on-going activities of our welding/fabricated industries for mutual benefits of both industries and members of IIW-India as well as readers of IWJ both in India and other countries. We need a group of enthusiastic industry members providing networking and means of communicating information about application of welding technology. After all welding technology is used a wide range of our industries and applications from micro-joining of medical devices, electronics etc. to large scale applications such as boilers and pressure vessels, bridges, defense and mining equipments, piping, ships, rail and road transport, water and gas pipe lines, nuclear etc. Interested members are welcome to make an active group which will be included in Editorial Board of our IWJ in order to provide scientific and technical information prevailing in our industries. We are sure that the inputs of the active group will further improve our IWJ with the ever brightening scenario on industrial sectors.

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H. Das ¹, T. K. Pal ¹

Affiliations
1 Welding Technology Centre, Metallurgical and Material Engg. Dept, Jadavpur University, Kolkata, IN

Abstract

Multi-material fabrication such as joining of steel and aluminium has become prominence now a days in automotive industries. Friction Stir Welding (FSW), a novel solid state welding process, has already established good joint strength between steel and aluminium; but joint fatigue strength of such dissimilar material has not yet been explored. In the present study, the friction stir lap welding has been performed at each rotation speeds of 500, 1000, 1500 rpm for two different travel speed i.e. 50 and 100 mm min-1 at a constant probe depth 2.5 mm. Among the different joints, two joints: one achieved of maximum load (5 kN) and other achieved of minimum load (2 kN) have been exclusively characterized by high cycle fatigue at R=0.1. Furthermore, R ratio has been varied from +0.5, +0.3 to -0.5, -0.3 at endurance limit (106 cycles). The experimental results show that fatigue strength at 106 cycles for both the FS welded lap joint is about 20% of their respective failure load. Thus better fatigue strength is associated with the lap joint performed with the joint of maximum load. The fatigue behaviour of two FS joints has been correlated with the thickness of intermetallic compound evaluated by SEM image and accumulation of dislocations observed by TEM.

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T. K. Pal

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Change is one of the fundamental elements of human existence. In fact, change is one of few things about which we can be certain. That's why lot of expectation are in vogue from the new government. But those may vary from different classes of people in our society. At the same time government doesn't magically produce solutions to the existing problems in our country. It is the people of the country, decision makers, who are the enablers that provide solid ideas and have the drive to contribute constructively to our cause.

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T. K. Pal

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The International Congress of the International Institute of Welding (IC 2014) and 8^th International Welding Technology Exhibition (WELD INDIA 2014), to be held at Pragati Maidan, New Delhi, will bring forth the complete flavour of the IIW-India community. The Indian Welding Journal, published quarterly in technical association with American Welding Society, welcomes all delegates to this gala technical festival. The Editorial Board joins me in congratulating all the Award Winners for the year 2013.

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T. K. Pal

Abstract

In this issue we have two papers on joining of non-ferrous metal and alloys-one from the group of Dr. G. Madhusudhan Reddy who are all most regular contributor to IWJ and other from the group of Dr. V. Balasubramanian who are also equally contributing to IWJ. The paper on "Studies on partially melted zone and pitting corrosion resistance of A 356 aluminium-silicon alloy GTA welds" is of practical importance as the suitability of available techniques in improving weld performance is always demanded by the industries. Furthermore, the corrosion resistance affected by microstructural aspects of Al-Si welds would be interest to the researchers as well.

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T. K. Pal

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I suppose everyone has made a New Year's resolution. We all know that none of us will remain true to our commitments for the entire year. If we really did, then we would not have to make the same resolutions from one year to the next.

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T. K. Pal

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Our country is moving into another economical revolution and, if we are not prepared to meet the challenge, we will be relegated to a minor role in the global scheme of industry. The economic outlook for the Indian welding fabrication industry is not bleak despite some recent difficulties. Overall economic parameters are favorable with the combination of relatively skilled work force with a favorable cost structure if compared to the highly industrialized country. Traditionally, the welding industry has drawn in work force from high school and ITI. Recently, due to significant development in welding technology such as welding process control, power sources with advanced wave forms and digitally controlled displays, robotic welding etc. skilled and trained workforce has become an important ingredient to an organization's success. IIW-India had made a fantastic effort in planning to improve the performance of welding industry through training and certification. Our new president Mr. P. K. Das has emphasized in the last AGM held at Kolkata on 29.09.12 for implementing the concept of national plan for the industry. Our welding industry must take a stand on obtaining proper use of strong work force to accomplishing their goal.

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T. K. Pal

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During the last few years the energy consumption, prevention of energy waste and a battement of green house gas emissions have become key operational features for industries globally. Reducing emissions growth will require determined action by all members of industry and to improve awareness and understanding of green house issues, reduce green house shink capacity and develop adoption responses. As a part of challenge, industries are required to monitor their emissions and regularity report on achievements. Thus helping to ensure green house action becomes an intrinsic part of their business agenda. By providing the right information, advice and support, the IIW-India can promote cleaner and more efficient use of energy throughout the welding industry, lower green house gas emission and boost industry competitiveness.

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T. K. Pal

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Over the years, the growth of fabrication industry has generated a demand for quality weld deposition at ever faster rate with flexibility in operation. Welding processes are being developed to crater the need of the fabrication industry. However, for better flexibility in operation, the concepts of hybrid process are now being implemented commercially. But to get maximum benefit of such potential hybrid processes, it is necessary to establish first the technical characteristic of the process. These have been discussed lucidly by Dr. G. Padmanabham et al in his paper "LASER-MIG Hybrid Welding of Thick Plates of Mild Steel in Single Pass" which many of us would find very informative and relevant.

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H. Das ¹, T. K. Pal ¹

Affiliations
1 Welding Technology Centre, Metallurgical & Material Engineering Department, Jadavpur University, Kolkata-700032, IN

Abstract

Corrosion prevention is a major concern for naval structures particularly for welded joint of high strength steel. Although cathodic protection (CP) is still widely used to prevent corrosion of structural steels in marine environment, effectiveness of CP has not been proven for structural steels with a yield stress above 400 MPa. In the present investigation, high strength steel plate of DMR 249A was welded by Submerged Arc Welding (SAW) process and the corrosion fatigue tests were performed on weld metal in air and 3.5% NaCl solution at room temperature with R ratio of 0.1 and a cyclic frequency of 0.01 Hz with and without cathodic potential. Optimum cathodic potential for weld metal was also evaluated in unstressed condition from the minimum corrosion coefficient among four potentials (under at -800, -875, -950, -1025) mV based on potentiostatic polarization curves (E_corr value) of weld metal. Corrosion fatigue results suggest that optimum cathodic potential data (-875 mV) determined in unstressed condition could be used to improve the corrosion fatigue life of weld metal used in naval structure.

Keywords

High Strength Steel, SAW, Fatigue Crack Growth Rate (FCGR), Polarization Curve, Corrosion Coefficient, Corrosion Fatigue.

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T. K. Pal

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First of all I would like to thank council members of The Indian Institute of Welding for giving me the opportunity to act as Chief Editor of Indian Welding Journal from January issue.

You will agree that the economic growth of India over the period has changed her position and has involved changes in her industrial structure. These changes greatly affect the status of welding engineering and technology in the present industrial society. The Indian Institute of Welding has also decided to restructure itself to adopt to these new environments.

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T. K. Pal ¹

Affiliations
1 Jadavpur University, Calcutta, IN

Abstract

Controlled Shot Peening is recognised and widely accepted as a process to increase fatigue strength and stress corrosion cracking and extend life of fabricated components, particularly in high performance applications, by the introduction of compressive residual stress.

Fatgue and stress corrosion cracking are also problems commonly encountered, in many areas of industrial activity, where beneficial residual stress induced by controlled shot peening can provide a cost efficient solution.

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T. K. Pal ¹

Affiliations
1 Metallurgical Engineering Department, Jadavpur University, Calcutta - 700 032, IN

Abstract

The effect of nickel and aluminium on the microstructure and mechanical properties in SG iron weld metal have been investigated.

It is found that both nickel and aluminium influence the microstructure Nickel increases nodule count and pearlite content. Aluminium decreases nodule count and promotes ferrite formation. Addition of nickel in SG iron weld metal upto 3.95 percent, results in an increase in tensile strength and decrease in ductility Further inprovement in tensile strength and marginal drop in ductility have been observed with the addition of aluminium in SG iron metal containing nickel.

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T. K. Pal ¹

Affiliations
1 Metallurgical Engineering Department, Jadavpur University, Calcutta 700 032, IN

Abstract

This paper highlights different methods for the assessment of fracture resistance in welded steel structures. Fracture mechanics approaches have very useful in providing methods for fracture control in welded steel structures, but it needs to be recognised that different approaches are required to assert fracture control with different classes of structure.

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P. Kumar ¹, P. Majumdar ¹, T. K. Pal ¹

Affiliations
1 Department of Metallurgical Engineering, Student Jadavpur University, Calcutta-700 032, IN

Abstract

3.5% nickel steel possesses a combination of high strength and resistance to brittle fracture which makes it suitable to be widely used for the fabrication of storage tanks designed to be used at between 223K and 172K (pressure vessels to produce ethylene or propylene from naptha in chemical plant)[1-4].

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G. Chakraborty ¹, T. K. Pal ¹, S. Palit Sagar ², N. Parida ²

Affiliations
1 Welding Technology Center, Metallurgical Engg Dept, Jadavpur University, Kolkata - 700032, IN
2 National Metallurgical Laboratory, Jamshedpur - 831007, IN

Abstract

Spot weld quality in terms of soundness of joint and nugget penetrations have been evaluated by ultrasonic technique. Furthermore, the variations in ultrasonic attenuation characteristics caused by grain boundary scattering have been utilized to assess grain coarsening at weld metal due to spot welding heat. The interpretations of ultrasonic signals are found to correspond with the results obtained from peel off and shear tensile test and are at par with the optical and TEM observations.

Keywords

Ultrasonic Technique, Spot Weld, Grain Size, Dislocation Density, Attenuation.

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T. K. Pal

Abstract

The National Welding seminar: “NWS 2013” was held in Bangalore during February 7-9, 2013, the theme of the seminar being “Recent Developments in Welding Science and Technology”. The venue was Karnataka Trade Promotion Organization Center (KTPO), built as a conference center with avant-grade facilities for conferences and exhibitions. The organizers of IIW Bangalore branch has made the seminar first time at this venue.

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T. K. Pal

Abstract

The issue of the IWJ comes to you with a slightly new look. It shows Friction Welding of dissimilar weld joints. The cover design has been changed after four issues as per norms. However, we will invite our readers next time to send for a suitable design and finally it could be selected from all suggested designs in our G.R Committee.

The Indian Institute of Welding sagaciously organizes National and International events where from mutual benefits are drawn by all concerned. This time National weld meet (NWM 2013) is being organized by Baroda Branch on an interesting topic. Dissimilar welding which is almost common approach now in various sectors like automobiles, power plants, shipyards etc where mechanical properties are tailored to local requirement and their performance is often crucial to the function of the whole structure. For example, in automotive industry, the concept of using dissimilar functional material has derived mainly to improve fuel efficiency and reducing CO₂ gas emissions.

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T. K. Pal

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In recent years significant understanding of the welding processes and welding materials have been possible due to intense R & D work. New processes, new materials are being introduced and at the same time overall integrity requirements under severe service conditions are in demand by the codes and standards. Friction stir welding (FSW), for example, a novel solid-state welding process, is now available to the industries for full utilization of its vast potentialities. The FSW process is inherently simple, with few variables and other inherent advantages. However, lot of research works on FSW process are in progress to explore its technical characteristics interfacing with different materials as well as processes. This will develop more confidence among the fabricators and will undoubtedly increase the domain of existing applications. FSW is already been applied in aircraft, ship building and automobile industry. Recently FSW process has been included in ASME Section IX for power plant application indicating gradual penetration in different sectors.

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P. Banerjee ¹, T. K. Pal ¹, M. Shome ²

Affiliations
1 Welding Technology Centre, Metallurgical & Material Engineering Department, Jadavpur University, Kolkata - 700032, IN
2 Material Characterization and Joining, R & D, Tata Steel Ltd., Jamshedpur - 831001, IN

Abstract

The automotive companies are quickly changing their material bill from low strength formable grades to advanced high strength steels (AHSS) in response to the global call for preserving a green environment and enhanced passenger safety. As compared to low carbon formable steels, the AHSS steels are relatively difficult to weld by the traditional processes and the joint performance is below expected levels. Thereby conventional manufacturing processes are being challenged, and new processes with improved service performance are being increasingly explored. Fatigue performance of material joints is a key design input and indicator of the performance of automobiles during service, particularly for AHSS. In this paper, primary joining process such as spot welding and emerging hybrid joining process such as weld-bonding were carried out on two commercially available AHS dual phase (DP590, DP780) automotive steels. Two dimensional spot welding lobes were developed for each of the steels following nugget diameter criteria of 4 √t to 5.5 √t, where t is the thickness of the sheets. By selecting two sets of parameters from the lobes, spot welding was carried out on shear-tension sheet samples with an AC type resistance spot welding machine. Weld-bonding was done by applying a thin layer of high strength epoxy based structural adhesive followed by spot welding on two overlapping sheet samples. Static shear tensile and fatigue properties under tension-tension mode for all the spot welded and weld-bonded joints of DP590 and DP780 steels were evaluated and compared.

Keywords

Weldability Lobe, DP Steels, Weld Bonding, Shear Tensile Strength, High Cycle Fatigue Performance.

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P. K. Mandal ¹, T. K. Pal ²

Affiliations
1 Welding Technology Centre, Metallurgical and Material Engg. Dept., Jadavpur University, Kolkata - 700 032, IN
2 Welding Technology Centre, Metallurgical and Material Engg. Dept., Jadavpur University, Kolkata - 700 032, IN

Abstract

Preliminary investigation on impression creep behaviour of different zones (base metal, weld metal and Heat Affected Zone) of similar and dissimilar Cr-Mo steel welded joints in as welded and PWHT conditions has been attempted. It has been possible to evaluate the steady state creep rate of different zones and PWHT has shown a detrimental effect on the impression creep resistance of all weldments.

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T. K. Pal ¹

Affiliations
1 Welding Technology Centre, Metallurgical & Material Engineering Department, Jadavpur University, Kolkata, IN

Abstract

The paper deals with science and technology of several specific areas of welding that have advanced sufficiently in recent years and highlighting the futuristic path of development.

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T. K. Pal ¹, S. Neogy ²

Affiliations
1 Metallurgical Engg. Dept., Jadavpur University, Kolkata - 700032, IN
2 Jadavpur University, IN

Abstract

The effect of welding conditions, technique and filler wire type have been studied to understand their effect on the size and width of nondendritic equiaxed grain of GTA weld in alloy 1441-T8. The microstructure of all the welds exhibited a fusion boundary equiaxed zone (EQZ). In addition to heat input, filler wire type and welding technique are found to have considerable effect on the grain size and width of EQZ.

Keywords

Fusion Boundary, Equiaxed Zone (EQZ), Partially Melted Zone, Fusion Zone, GTA Welding, Pulsating Technique.

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T. K. Pal

Abstract

Copper and Copper alloys are used for their electrical and thermal conductivity, corrosion and oxidation resistance and distinctive aesthetic appearance. Copper is widely used for electrical conductors and for manufacture of electrical equipment. They are also used in reaction pressure vessels, evaporators, distillation columns, heat exchangers and for components in process industries like chemical, petrochemical, fertilizer, etc.

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T. K. Pal ¹

Affiliations
1 Department of Metallurgical Engineering, Jadavpur, Calcutta, IN

Abstract

The toughness of weld metal is a factor of critical importance that governs the safety of welded structures. Considering that the trend is towards higher heat input in welding and that environmental and use conditions of structures are becoming increasingly severe, it is imperative to take comprehensive measures to improve the toughness of the weld metal.

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T. K. Pal ¹

Affiliations
1 Metallurgical Engg. Department Jadavpur University, Calcutta - 700 032, IN

Abstract

Wear is a major problem leading to the replacement of components and assemblies in engineering industries. For many years welding technology has supplied an effective means of protecting the surface of engineering components which would otherwise be scrapped. To protect parts against mineral wear, chromium-containing Fe-C surfacing alloys are in use for deposit welding. Besides the chemical composition, the properties of such coating alloys are influenced mainly by specific welding parameters. The welding conditions, in particular the cooling rate of the deposited material, have important influence on the microstructure of the coating, and therefore on the hardness and wear resistance.

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