Effects of the Process Parameters on Beads by Plasma Arc Welding of the Membrane for LNG Ships

2007 ◽  
Vol 26-28 ◽  
pp. 507-510 ◽  
Author(s):  
B.J. Kim ◽  
Y.R. Son ◽  
J.O. Yun ◽  
Jeong Soo Lee
Keyword(s):  
Process Parameters ◽  
Gas Flow ◽  
Welding Process ◽  
Welding Current ◽  
Tensile Tests ◽  
Optimum Process ◽  
Plasma Welding ◽  
Lap Welding ◽  
Etched Surface ◽  
Membrane Sheet

The membrane, which forms the primary barrier of the cargo tank onboard LNG carrier, is made of corrugated sheets, angle pieces and sealing caps and so on. These components are manufactured from SUS 304L sheets of 1.2mm thickness and assembled by the plasma welding. There are several welding defects such as overlap, excessive convexity, excessive concavity of weld and incomplete inclusion in the plasma welding. These unacceptable portions of the weld should be removed and repaired in order to prevent propagation of the defects. So a study is undertaken to determine the optimum process parameters such as the welding current, traveling speed, gas flow rates and frequency in the plasma lap welding process for LNG ships in order to prevent these defects. The polished and etched surface of the welded membrane sheet is examined if the cross section shows a properly made weld. And the tensile tests are conducted to consider if the tensile strength is less than the minimum required for the parent metal of the membrane sheet.

scholarly journals Comparison between PCA analysis and Grey based Taguchi analysis of TIG welding process parameters on Duplex stainless steel

2021 ◽  
pp. 67-74
Author(s):  
Sandip Mondal ◽  
Goutam Nandi ◽  
Pradip Kumar Pal
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Process Parameters ◽  
Gas Flow ◽  
Welding Process ◽  
Principal Component ◽  
Welding Current ◽  
Tig Welding ◽  
Welding Parameters ◽  
Welding Quality

Tungsten inert gas (TIG) welding on Duplex stainless steel (DSS) is more easy, comfortable and useful, if the process is precisely understood and controlled through development of the science & technology. TIG welding on DSS has been performed with the help of specific controlled welding process parameters. Welding quality has been strongly depended on these process parameters. In this study, some valuable welding parameters are chosen. These are welding current, shielding gas flow rate and speed of welding. These process parameters of TIG welding for ASTM/UNS 2205 DSS welds are optimized by using Principal Component Analysis (PCA) method and Grey based Taguchi’s L9 Orthogonal array (OA) experimental plan with the conception of signal to noise ratio (N/S). After that, compression results of above mentioned two analyses of TIG welding process parameters have been calculated. The quality of the TIG welding on DSS has been evaluated in term of ultimate tensile strength, yield strength and percentage of elongation. Compression results of both analyses indicate application feasibility for continuous improvement of welding quality on DSS in different components of chemical, oil and gas industries.

Parametric Studies on TIG Welding of 316L Stainless Steel by RSM and TLBO

2019 ◽  
Vol 969 ◽  
pp. 744-749 ◽  
Author(s):  
Shubhash Chandra Moi ◽  
Ramesh Rudrapati ◽  
Asish Bandyopadhyay ◽  
Pradip Kumar Pal
Keyword(s):  
Gas Flow ◽  
Welding Process ◽  
Austenitic Stainless Steels ◽  
Welding Current ◽  
Tensile Tests ◽  
Tig Welding ◽  
Welding Parameters ◽  
Welding Operation ◽  
Input Parameters ◽  
Contour Plots

Present study is planned to analyze the effects of welding process parameters on quality characteristics of TIG welded 316L austenitic stainless steels (ASS). The input parameters considered in the study are: welding current, speed and gas flow rate. Butt-joints of ASS sheets have been made as per Box-Behnken design of response surface methodology (RSM). After welding operation, tensile tests have been conducted on welded samples and observations of ultimate tensile strength (UTS) has been noted. Mathematical modeling has been made to relate the input parameters and output response by RSM. Teaching leaning-based optimization (TLBO) approach has been used to optimize the UTS. The influences of input welding parameters on UTS has been studied and analyzed through contour plots. Confirmatory tests have been conducted to validate the predicted parametric condition obtained by integrated RSM and TLBO. From the study, it is found that RSM and TLBO is efficient to maximize UTS in TIG welding operation.

scholarly journals Welding Process Optimization of WELDOX960 High Strength Steel

2018 ◽  
Vol 207 ◽  
pp. 04005
Author(s):  
Min Hu
Keyword(s):  
Penetration Depth ◽  
Process Optimization ◽  
Process Parameters ◽  
Welding Speed ◽  
High Strength Steel ◽  
Welding Process ◽  
Welding Current ◽  
High Strength ◽  
Influence Of Process Parameters ◽  
Steel Analysis

This paper studies WELDOX960 high strength steel, analysis of the welding ability of WELDOX960 high strength steel. Analyze the weld ability of WELDOX960 high-strength steel materials, and study the influence of process parameters such as welding current, welding voltage, and welding speed on penetration depth and weld width in the automated welding process. Through this test, the welding process is optimized to ensure the weld quality. The results show that WELDOX960 high-strength steel adopts multi-layer and multi-pass welding to form better welds.

Enhancing fatigue resistance of activated tungsten inert gas welded UNS S32750 super duplex stainless steel by optimizing its technological properties

2020 ◽  
pp. 1-11
Author(s):  
A. Arunmani ◽  
T. Senthilkumar
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Fatigue Resistance ◽  
Process Parameters ◽  
Gas Flow ◽  
Welding Process ◽  
Travel Speed ◽  
Inert Gas ◽  
Super Duplex Stainless Steel

In engineering industries and heavy manufacturing plants, fatigue life of joints plays a pivotal role in determining the overall life span of the welded joint. In this paper, an advanced fusion joining technique, namely activated tungsten inert gas welding, was used for joining UNS S32750 super duplex stainless steel, with ZnO as activation flux. For the enhancement of fatigue resistance of joints, important welding process parameters were fluctuated according to a developed central composite design model. Empirical relationships were developed between the process parameters and the fatigue strength of the joints, which was correlated with the number of cycles to failure (NCF). Using analysis of variance, the significance of the developed fatigue model was ascertained. Using response surface methodology, optimization of process parameters for enhancement of fatigue resistance was done. It was observed that at the optimized activated tungsten inert gas weld process parameters of travel speed of welding torch at 69.85 mm/min, weld current at 125.20 A, and shielding gas flow rate at 14.77 L/min, a high fatigue life of 7.66396 × 108 NCF was obtained and the model was validated to very high predictability. Microstructural variations in the fatigue-tested specimens were evaluated for identifying the grain modifications.

Optimization of Friction Stir Welding Process Parameters to Join Al 5052 and Al 6061 Alloy Plates Using Grey-Taguchi Technique

2017 ◽  
Author(s):  
R. Sandeep ◽  
D. Sudhakara ◽  
G. Prasanthi
Keyword(s):  
Friction Stir Welding ◽  
Process Parameters ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Fusion Welding ◽  
Optimum Process ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Grey Analysis ◽  
Grey Taguchi

Friction stir welding (FSW) is a solid state welding process used for welding similar and dissimilar materials. The process is widely used because it does not have common problems such as solidification and liquefaction cracking associated with the fusion welding techniques. The objective of the present research is to find the best combination of friction stir welding process parameters to join aluminium 5052 and 6061 alloy materials. The combination of process parameters is helpful to improve ultimate tensile strength, yield strength, percentage of elongation and hardness of welded joint. To achieve the research objective taguchi based grey analysis was used. The optimum process parameters were found be at rotational speed is 1400 rpm, transverse speed of 100 mm/min and axial force is at 11 KN.

scholarly journals Effect of welding sequence and welding current on distortion, mechanical properties and metallurgical observations of orbital pipe welding on SS 316L

2021 ◽  
Vol 2 (12 (110)) ◽  
pp. 22-31
Author(s):  
Agus Widyianto ◽  
Ario Sunar Baskoro ◽  
Gandjar Kiswanto ◽  
Muhamad Fathin Ginanjar Ganeswara
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Welding Process ◽  
Welding Current ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Depth Of Penetration ◽  
Welding Sequence ◽  
Pipe Welding

Orbital pipe welding was often used to manufacture piping systems. In orbital pipe welding, a major challenge is the welding torch’s position during the welding process, so that additional methods are needed to overcome these challenges. This paper discusses the influence of welding sequence and welding current on distortion, mechanical properties and metallurgical observations in orbital pipe welding with SS 316L pipe square butt joints. The variation of the orbital pipe welding parameters used is welding current and welding sequence. The welding current used is 100 A, 110 A, and 120 A, while the welding sequence used is one sequence, two sequences, three sequences, and four sequences. The welding results will be analyzed from distortion measurement, mechanical properties test and metallurgical observations. Distortion measurements are made on the pipe before welding and after welding. Testing of mechanical properties includes tensile tests and microhardness tests, while metallurgical observations include macrostructure and microstructural observations. The results show that maximum axial distortion, transverse distortion, ovality, and taper occurred at a welding current of 120 A with four sequences of 445 µm, 300 µm, 195 µm, and 275 µm, respectively. The decrease in ultimate tensile strength is 51 % compared to the base metal’s ultimate tensile strength. Horizontal and vertical microhardness tests show that welding with one sequence produces the greatest microhardness value, but there is a decrease in the microhardness value using welding with two to four sequences. Orbital pipe welding results in different depths of penetration at each pipe position. The largest and smallest depth of penetration was 4.11 mm and 1.60 mm, respectively

scholarly journals Optimization of TIG Welding Parameters for the 202 Stainless Steel Using NSGA-II

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Neeraj Sharma ◽  
◽  
Wathiq Sleam Abduallah ◽  
Manish Garg ◽  
Rahul Dev Gupta ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Flow Rate ◽  
Gas Flow ◽  
Welding Process ◽  
Welding Current ◽  
Welding Parameters ◽  
Shielding Gas ◽  
Gas Flow Rate ◽  
Electrode Diameter ◽  
Weld Region

Tungsten Inert Gas welding is a fusion welding process having very wide industrial applicability. In the present study, an attempt has been made to optimize the input process variables (electrode diameter, shielding gas, gas flow rate, welding current, and groove angle) that affect the output responses, i.e., hardness and tensile strength at weld center of the weld metal SS202. The hardness is measured using Vicker hardness method; however, tensile strength is evaluated by performing tensile test on welded specimens. Taguchi based design of experiments was used for experimental planning, and the results were studied using analysis of variance. The results show that, for tensile strength of the welded specimens, welding current and electrode diameter are the two most significant factors with P values of 0.002 and 0.030 for mean analysis, whereas higher tensile strength was observed when the electrode diameter used was 1.5 mm, shielding gas used was helium, gas flow rate was 15 L/min, welding current was 240A, and a groove angle of 60o was used. Welding current was found to be the most significant factor with a P value of 0.009 leading to a change in hardness at weld region. The hardness at weld region tends to decrease significantly with the increase in welding current from 160-240A. The different shielding gases and groove angle do not show any significant effect on tensile strength and hardness at weld center. These response variables were evaluated at 95% confidence interval, and the confirmation test was performed on suggested optimal process variable. The obtained results were compared with estimated mean value, which were lying within ±5%.

Development of Predictive Model for Quality Output of Welding Process of Steel NST 37-2 Using Response Surface Methodology

2018 ◽  
Vol 29 ◽  
pp. 12-18
Author(s):  
Lateef O. Mudashiru ◽  
Emmanuel O. Sangotayo ◽  
Samuel O. Alamu
Keyword(s):  
Tensile Strength ◽  
Welding Speed ◽  
Welding Process ◽  
Welding Current ◽  
Steel Sample ◽  
Quality Data ◽  
Optimum Process ◽  
Current Electrode ◽  
Welded Steel ◽  
Output Quality

The present study investigated the effect of operating parameters in modeling the output quality of welding process of steel sample. A three factor, three levels Box-Behnken Design (BBD) of RSM was applied to determine the effects of three independent variables (welding speed (A), welding current (B) and electrode potential (C)) on the tensile strength and to also develop a model for predicting the output quality. Data analysis shows that A, C, AB, BC, A2, B2and C2are the terms which significantly affected the ultimate tensile strength of the sample at 95% confidence level. The experimental values were very close to the predicted values and were not statistically different at p<0.05. The maximum tensile strength of 228 MPa was obtained at 250 A current, electrode diameter of 3.25 mm and 50 cm/min welding speed, respectively. The regression model obtained has provided a basis for selecting optimum process parameters for the improving output quality (tensile strength) of the welded steel sample.

A Study on Parameter Optimization With Numerical Heat Conduction Model For Circumferential Gas Tungsten Arc (GTA) Welding of Thin Pipes

1992 ◽  
Vol 206 (2) ◽  
pp. 101-111 ◽  
Author(s):  
T-J Lho ◽  
S-J Na
Keyword(s):  
Heat Conduction ◽  
Process Parameters ◽  
Small Diameter ◽  
Welding Current ◽  
Gta Welding ◽  
Optimum Process ◽  
Bead Width ◽  
Welding Condition ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

One of the important problems to be solved in welding engineering is to develop a mathematical method for the determination of optimum process parameters. In order to estimate the optimal process parameters in circumferential gas tungsten arc (GTA) welding of thin pipes, an objective was chosen to maintain a uniform bead width over the full circumferential joint, while the constraints consist of the capacity limit of the welding power source and equipment used. A transient three-dimensional finite difference model (FDM) of the heat conduction flow in the circumferential GTA welding of pipes was adopted for calculating the temperature field considering the temperature-dependent thermal properties of the workpiece, and consequently for determining the resultant bead width in circumferential welding of the pipe workpiece. An efficient optimization model for the numerical heat conduction flow was proposed to evaluate the optimal welding current with a given welding velocity for a required bead width. Its solution was obtained by employing the steepest descent method (SDM), where the initial value of the welding current was estimated by using the linear complementary problem (LCP), and the welding currents in the middle part of the pipe were interpolated by the least-squares approximation method of the second order. The experimental results of the bead formation showed that the developed mathematical model can be effectively applied to obtain the optimal welding condition in circumferential welding of thin pipes, especially thin pipes with a small diameter and high thermal conductivity.

INVESTIGATION OF TENSILE BEHAVIOUR OF TIG WELDED 316 STAINLESS STEEL USING TAGUCHI TECHNIQUES

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Karthimani T ◽  
Babu N
Keyword(s):  
Stainless Steel ◽  
Welding Speed ◽  
Gas Flow ◽  
Welding Process ◽  
Welding Current ◽  
Tig Welding ◽  
Filler Material ◽  
Tensile Behaviour ◽  
Welding Parameters ◽  
Taguchi Technique

This works aims at the analysis and optimization of joining similar grades of stainless steel by TIG welding. TIG welding may use a filler material. There is a variant in the process which does not require filler material. Such process is known as Autogenous TIG welding process. The parameters like current, welding speed and gas flow rate are the variables in the study. The objective of this research is to determine the influence of various welding parameters on the weld bead of 316 SS by using Taguchi technique. A plan of experiments based on Taguchi technique method has been carried out. Orthogonal array, signal to noise (S/N) Ratio, Analysis of variance (ANOVA) are employed for studying the welding characteristics of material & to optimize the weld parameters. The result obtained are the output from each parameter, through which optimal parameters are found out for maximum tensile strength. It is found that -welding current followed by welding speed are major parameters influencing mechanical properties of welded joint

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