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Chattopadhyaya, S.
- Identification and Assessment of the HAZ Softening and Hardening Phenomena for Submerged Arc Welding Process for Structural Steel Plates
Authors
1 Department of Mechanical Engg. Govt Engineering College, Kalyani, W.B,, IN
2 MECON India Ltd., Ranchi, IN
3 Department of Mechanical Engg. & Mining Machinery Engg., Indian School of Mines, University, Dhanbad, IN
Source
Indian Welding Journal, Vol 42, No 2 (2009), Pagination: 37-42Abstract
Submerged Arc Welding (SAW) process has lot of social and economical implication. Critical set of variables are involved in this process, and they are needed to be controlled. An attempt has been made in this paper to find out- the influence of the heat input on HAZ hardness (change of hardness & microstructure) for Submerged Arc Welding Process of Mild steel plates. Mild steel plates are welded by changing input variables (current, voltage, trolley speed, i.e. heat input) and Rockwell hardness No. on different grid points (points are taken horizontally & vertically 2 mm apart) of welded surface and at the zone adjacent to the welded portion has been observed. A detailed analysis of the microstructure changes is carried out to understand the HAZ softening phenomenon.
Keywords
SAW, HAZ Hardness, Rockwell Hardness No., Microstructure, Grain Growth.
- Indepth Investigations into the Capability of Plazma Arc Cutting of Mild Steel Tubes
Authors
1 Department of Mechanical Engineering & Mining Machinery Engineering, Indian School of Mines University, Dhanbad, IN
2 Mecon Ltd., Ranchi, IN
Source
Indian Welding Journal, Vol 42, No 3 (2009), Pagination: 58-64Abstract
Plasma Arc cutting (PAC) is a process of cutting steel and other metals (or sometimes other materials) using a plasma torch. In this method, an inert gas (in some units, compressed air) is blown at high speed out of a nozzle. At the same time an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to plasma. The plasma is sufficiently hot to melt the metal being cut and moves sufficiently fast to blow molten metal away from the cut. Plasma can also be used for plasma arc welding and other applications. In Plasma Arc Cutting (PAC), the plasma gas flow is enhanced so that the intense and deeply penetrating plasma jet cuts through the material and molten material is removed as cutting dross. PAC differs from oxy-fuel cutting in that the plasma process operates by using the arc to melt the metal whereas in the oxy-fuel process, the oxygen oxidizes the metal and the heat from the exothermic reaction melts the metal. Unlike oxy-fuel cutting, the PAC process can be applied to cutting metals which form refractory oxides such as stainless steel, cast iron, aluminum, and other non-ferrous alloys. In this paper the deviations in the thickness of the cut profile of the square tubes are critically analyzed for assessment of the deviations in the cut surface of the square tubes of structural steel due to the phenomena like top edge rounding, dross, cut surface bevel angle, top spatter and extended kerf width etc.
Keywords
Top Edge Rounding, Kerf Width, Dross, Top Spatter, Cut Surface Bevel Angle.- Analysis of The Influence of The Heat Input and Bead Volume on HAZ Hardness for Submerged Arc Welding Process of Mild Steel Plates
Authors
1 Department of Mechanical Engineering and Mining Machinery Engineering, ISMU, Dhanbad, IN
2 Departments of Mechanical Engineering, Kalyani Govt. Engineering College, Kalyani, W.B.,, IN
3 MECON Limited, Ranchi, Jharkhand, IN
Source
Indian Welding Journal, Vol 41, No 3 (2008), Pagination: 46-51Abstract
In Submerged Arc Welding process involves critical set of variables which are needed to control. An attempt has been made in this paper to find out- the influence of the heat input and bead volume on HAZ Hardness for Submerged Arc Welding Process of Mild steel plates. Mild steel plates are welded by changing input variables (current, voltage, trolley speed, i.e. heat input) and Rockwell hardness no. has been observed on welded portion and at the zone adjacent to the welded portion. A detailed analysis of the microstructure changes is carried out to understand the HAZ softening phenomenon.
Keywords
SAW, Microstructure, HAZ, Hardness.- An Analytical Approach towards the Interactive Behavior of the Confounded Parameters of Submerged Arc Welding Process for Mild Steel Plates
Authors
1 Department of Management Studies
2 Dept of Mechanical Engineering & Mining, Machinery Engineering, Indian School of Mines, IN
3 MECON Ltd, Ranchi, IN
Source
Indian Welding Journal, Vol 40, No 2 (2007), Pagination: 24-31Abstract
This paper deals with the Study of the Interactions of the Confounded Parameters of Submerged Arc Welding Process for Welding Mild Steel Plates of Higher thicknesses. Here the thickness of the plate is more than 10 mm. This experimental study was conducted at the workshop of Indian School of Mines, (Dhanbad). For this study MEMCO semiautomatic welding equipment with constant voltage rectifier was used. Specifications are as below:
Input voltage supply- 380/440 volts
Welding speed Trolley-30 to 1200 mm/min
3 Phase,50/60 Hz cycle. Air cooled
Wire feed speed-100 to 8000 mm per minute.
Output current 600 amps
Wire diameter -2 to 5 mm
Duty cycle 100%
Open circuit voltage 56 Volts, 35 Kva
Flux hopper capacity 12.5 kg
Deposition rate- 4 to 6 kg/hr
Wire flux ratio-1: 1
Flux used: ADOR Auto melt
GrII AWS/SFA 5.17(Granular flux)
Test Piece: 190mm X 90mm X 12mm
Weld position flat
Electrode positive and perpendicular to the plate.
The SAW process has been chosen for this application because of the complex set of variables involved in the process. Submerged arc welding (SAW) is a high quality, very high deposition rate welding process commonly used to join plate. SAW is usually operated as a fully mechanized or automatic process, but it can be semi-automatic also Submerged arc welding provides a purer and cleaner high volume weld which is also faster than traditional welding methods. The SAW process is much more critical because of its application in welding critical parts, equipments and machinery which have huge economic and social implications. Welding parameters: current, arc voltage and travel speed all affect bead shape, depth of penetration and chemical composition of the deposited weld metal. Because the operator cannot see the weld pool, greater reliance must be placed on parameter settings’.
In this study the parameters among current, arc voltage, and travel speed were varied and then the readings for penetration, bead width, metal deposition rate and time were taken. Welding parameters were noted during actual welding to determine the fluctuations. The same procedure is repeated many times to achieve more accurate results. On the bases of these readings graphs were plotted between the parameters to study the interactions of the parameters with each other. The main objective being to identify the main input factors, to determine the interactions amongst the input factors and finally to establish the optimum settings for the input factors the response output being weld bead parameters.
Keywords
SAW, Confounded Parameters, Bead Parameters.- Weldbead Parametric Estimation of SAW Process Through Neural Network
Authors
1 Dept., Kalyani Govt Engg. College, Kaiyani, IN
2 Mecon Limited, Ranchi, IN
3 Department of Mechanical Engg. & Mining Machinery Engg. Indian School of Mines University, Dhanbad, IN
Source
Indian Welding Journal, Vol 40, No 4 (2007), Pagination: 33-43Abstract
In this paper, an attempt has been taken to develop a model to predict the yield characteristics (weld bead parameters) of Submerged Arc Welding (SAW) process with the help of neural network technique. The SAW process has been chosen for this application because of the complex set of variables and high set up cost involved in the process as well as its significant application in the manufacturing of critical equipments which have a lot of economic and social implications.
Under this study the neural network model has been trained according to the actual inputs and outputs.
After completing training, the desired inputs have been given to the model and it gives the estimated output value. And according to this we can also estimate the error between the actual and predicted results. Neural network is implemented here because of having remarkable ability to derive meaning from complicated or imprecise data and can be used to extract patterns and detect trends that are too complex to be noticed by either humans or other computer techniques. Hence a trained neural network can be thought of as an "expert" in the category of information it has been given to analyses.