Empirical Assessment Method of Ultimate Capability of Steel Stiffened Panel under Longitudinal Compressive Load

2021 ◽  
pp. 1-13
Author(s):  
Jin Pan ◽  
Tao Wang ◽  
Ming Cai Xu ◽  
Gui Gao
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Welded Joint ◽  
Compressive Load ◽  
Welding Current ◽  
Liquid Films ◽  
Assessment Method ◽  
Welding Parameters ◽  
Stiffened Panel ◽  
Welding Seam

Experiment of automatic gas tungsten arc welding of liquefied natural gas carrier Invar alloy with a thickness of .7 mm was completed, and the welding parameters were optimized, as well as microstructure and mechanical properties of the welded joint were measured and analyzed. The grain size of the area near the weld centerline was small, mainly cellular dendrites, and the grain size on both sides of the weld centerline increased gradually, mainly dendrites, whereas the grain size near fusion line was larger, and there were more columnar crystals. The heat-affected zone was composed of coarse austenite grains. Transgranular cracks were the main cracks in the welding seam. When welding current was 40 A, frequency was 120 Hz, and welding speed was 350 mm/min, tensile strength of the welded joint was 446.9 MPa, which 88.1% of the base metal’s tensile strength and 10.3% of the fracture elongation. The fracture surface of tensile specimens showed typical plastic fracture characteristics, with no obvious crack characteristics, and no eutectic liquid films were observed.

Microstructure and Mechanical Properties of GTAW Welded Joint of Invar Alloy

2021 ◽  
pp. 1-8
Author(s):  
DongSheng Zhao ◽  
TianFei Zhang ◽  
LiangLiang Wu ◽  
LeLe Kong ◽  
YuJun Liu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Welded Joint ◽  
Welding Current ◽  
Liquid Films ◽  
Invar Alloy ◽  
Welding Parameters ◽  
Welding Seam ◽  
Microstructure And Mechanical Properties

Experiment of automatic gas tungsten arc welding of liquefied natural gas carrier Invar alloy with a thickness of .7 mm was completed, and the welding parameters were optimized, as well as microstructure and mechanical properties of the welded joint were measured and analyzed. The grain size of the area near the weld centerline was small, mainly cellular dendrites, and the grain size on both sides of the weld centerline increased gradually, mainly dendrites, whereas the grain size near fusion line was larger, and there were more columnar crystals. The heat-affected zone was composed of coarse austenite grains. Transgranular cracks were the main cracks in the welding seam. When welding current was 40 A, frequency was 120 Hz, and welding speed was 350 mm/min, tensile strength of the welded joint was 446.9 MPa, which 88.1% of the base metal’s tensile strength and 10.3% of the fracture elongation. The fracture surface of tensile specimens showed typical plastic fracture characteristics, with no obvious crack characteristics, and no eutectic liquid films were observed.

Effect of friction stir welding parameters on properties and structure of 1151T alloy sheets joints

2021 ◽  
pp. 11-18
Author(s):  
V.V. Ovchinnikov ◽  
A.M. Drits ◽  
I.V. Solov’eva
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Friction Stir Welding ◽  
Welded Joint ◽  
Welding Parameters ◽  
Natural Ageing ◽  
Friction Stir ◽  
Cooling Speed ◽  
T State

The mechanical and corrosive properties of welded joints of sheets with 6 mm thickness made of the 1151 alloy of the Al—Cu—Mg system in the T state (hardening and natural ageing) obtained by friction stir welding by single, double welding and bobbin tool welding is studied. It is shown that the change in the friction stir welding scheme does not result in noticeable change in the tensile strength of the welded joint and the weld metal. The grain size in the weld increased from 4.8 µm (single welding) to 10.5 µm when bobbin tool welding. The intercrystall line corrosion resistance of all welding zones (except the base metal) increases by about 1.4 to 2 times depending on the structural area due to the higher cooling speed of single friction stir welding compared to the bobbin tool welding,

Optimization of friction stir welding parameters of dissimilar aluminium alloys 6061 and 5083 by using response surface methodology

2021 ◽  
pp. 095440622110058
Author(s):  
Sanjeev Verma ◽  
Vinod Kumar
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Tilt Angle ◽  
Feed Rate ◽  
Aluminium Alloys ◽  
Welded Joint ◽  
Welding Parameters ◽  
Friction Stir ◽  
Industrial Sectors ◽  
Tool Pin

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.

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%.

Effect of Welding Parameters on the Tensile Strength of the Weld-Deposition Layer

2020 ◽  
Vol 861 ◽  
pp. 101-106
Author(s):  
Trung Do Thanh ◽  
Son Minh Pham ◽  
Cong Chinh Nguyen
Keyword(s):  
Tensile Strength ◽  
Welding Current ◽  
Numerical Control ◽  
Welding Parameters ◽  
Specific Data ◽  
Welding Technology ◽  
Experimental Process ◽  
Near Net Shape ◽  
Wire Arc Additive Manufacturing

In general, tensile strength is an important factors when evaluating the quality of a product. In this study, samples are created using Wire Arc Additive Manufacturing (WAAM) technology. WAAM technology is a combination of Metal Active Gas welding technology and Computer numerical control technology, and is used to create products with a near net shape. Experimental process parameters, such as welding speed and welding current, are implemented and a deposition layer test is performed, where samples are deposited, layer-upon-layer, and then face milled to ensure the correct dimensions are achieved before subsequent deposition. Using specialized testing equipment, specific data is obtained in order to determine the tensile strength of the sample. Statistical methods are then used to process the data and establish the effect of the parameters on the tensile strength of the sample.

Weld Repair of Shell Plates During Seagoing Operations

2002 ◽  
Author(s):  
Per R. M. Lindstro¨m ◽  
Anders Ulfvarson
Keyword(s):  
Grain Size ◽  
Theoretical Model ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Base Material ◽  
Forced Flow ◽  
Welding Parameters ◽  
Weld Repair ◽  
Welding Seam ◽  
Welding Procedure

An algorithm to estimate the cooling rate of welding seams on the shell plating of a ship, below the waterline, while it is on voyage has been derived. The demand for this technique has arisen from the wish of ship operators to make it possible for the safe repair of ship structures without taking them out of operation. [1] The strength of the shell plating after welding is determined by its metallurgic structure, which is dependent on the cooling rate, its chemical composition and the original grain size of the base material. [2] The cooling rate for this type of welding seam depends on the velocity of the water flow, the distance from the bow, the thickness of the plate, and the heat from the heat input of the welding. The algorithm makes it possible to calculate the cooling rate for a base material affected by a forced flow of fluid by means of Rosenthal’s equation and thus enabling suitable welding parameters to be determined. As the welding parameters can be chosen to fit the specific repair to be made, it is now possible to determine the suitability of a welding procedure in advance. The algorithm is applicable when determining welding parameters at Hot-Tapping operations as well, where the base material is affected by a forced flow of fluid. A number of experiments have been performed and the results support the theoretical model. The research project continues with the aim of finding an algorithm to include the enhanced cooling rate due to the layer of boiling fluid on the back of the base material. A method to improve the measurements of the most important parameter in the algorithm has been developed and makes it possible to build up a quantitative database of typical values for various configurations.

Experimental Study on Tensile Strength of Butt Joints for Mild Steel with Thickness 6mm Using Gas Metal Arc Welding (GMAW)

2017 ◽  
Vol 740 ◽  
pp. 155-160 ◽  
Author(s):  
Z.A. Zakaria ◽  
K.N.M. Hasan ◽  
M.F.A. Razak ◽  
Amirrudin Yaacob ◽  
A.R. Othman
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Heat Affected Zone ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Welding Parameter ◽  
Welding Parameters ◽  
Low Carbon ◽  
Metal Arc Welding

In this study, the effects of various welding parameters on welding strength in low carbon steel JIS G 3101 SS400, welded by gas metal arc welding were investigated. Welding current, arc voltage and travel speed are the variable parameters were studied in this study. The ultimate tensile strength, hardness and heat affected zone were measured for each specimen after the welding operations, and the effects of these parameters on strength were examined. Then, the relationship between welding parameter and ultimate tensile strength, hardness and heat affected zone were determined. Based on the finding, the best parameter is formulated and used to calculate the heat input.

scholarly journals The effect of welded joint properties on the surface characteristics of laser-welded 2205 duplex stainless steel

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879744 ◽  
Author(s):  
Shanshan Hu ◽  
Dongrui Zheng ◽  
Guolin Zhao ◽  
Guangliang Li ◽  
Hongqun Tang
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Surface Quality ◽  
Welded Joints ◽  
Welded Joint ◽  
Surface Characteristics ◽  
Welding Parameters ◽  
Joint Properties ◽  
Welding Surface

Welded joints of poor welding surface quality are sensitive to stress concentrations, affecting both the tensile strength of workpieces and the fluidity of liquids and gases in pressure and liquid containers. Orthogonal experiments involving the laser welding of 1-mm-thick duplex stainless steel sheets were conducted using different electric current, pulse width and frequency values in order to analyse the effect of welding properties on the surface characteristics of the welded joints. Rapid judgement regarding the welded joint properties was made based on the observed welding surface quality. The results show that an even phase proportion and grain refinement are not necessarily guaranteed to provide good welding surface quality. A satisfactory welding surface quality characterised by a smaller spot pitch or spot pitch difference, smaller weld width, reduced surface roughness and valley depth of surface waviness implies better welded joint mechanical characteristics and a more even microstructure. The specimen with the most suitable welding parameters and the greatest heat input can reach the lowest volume fraction of ferrite phase of 42.5% and the highest tensile strength of 848 MPa, and its surface quality is the best.

Study on YAG Laser Welding Process of Fe-Mn-Si Shape Memory Alloy

2010 ◽  
Vol 37-38 ◽  
pp. 1364-1367 ◽  
Author(s):  
Chao Yu Zhou ◽  
Cheng Xin Lin ◽  
Lin Lin Liu
Keyword(s):  
Tensile Strength ◽  
Shape Memory Alloy ◽  
Laser Welding ◽  
Shape Memory ◽  
Cross Section ◽  
Welded Joint ◽  
Processing Parameters ◽  
Welding Seam ◽  
Yag Laser ◽  
Optimal Processing

In this study, 1mm thick Fe-Mn-Si shape memory alloy was welded by both sides using YAG laser welding. In a certain range of parameters, the optimal processing parameters for the maximum tensile strength are current 100 A, pulse frequency 3 Hz and pulse width 15 ms by orthogonal experiment. With the optimal processing parameters, the tensile strength of the welded joint can achieve 94% of base material,and the fracture appears in the center of welding seam and the surface morphology of welding seam is good. The influence of processing parameters on tensile strength of weld joint is directly embodied in cross-section of the welding seam morphology. In the laser welding, the tensile strength of nonpenetration in seam and hourglass shape welded joint is generally poor, and the perfect welded joint has conditions such as wide welding seam, deep penetration, weld pool filling and “non-hollow”. Most importantly, the central area in cross-section of the welding seam is the widest.

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