scholarly journals Shielded Active Gas Forge Welding of an L80 Steel in a Small Scale Shielded Active Gas Forge Welding Machine

2021 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
Vinothkumar Palanisamy ◽  
Jan Ketil Solberg ◽  
Per Thomas Moe
Keyword(s):  
Weld Zone ◽  
Weld Line ◽  
Electrical Heating ◽  
Welding Parameters ◽  
Small Scale ◽  
Corrosion Properties ◽  
Welding Machine ◽  
Complete Set ◽  
Zone Microstructure ◽  
Grade Steel

The Shielded Active Gas Forge Welding (SAG-FW) method is a solid-state welding technique in which the mating surfaces are heated by induction heating or direct electrical heating before being forged together to form a weld. In this article, an API 5CT L80 grade carbon steel alloy has been welded using the SAG-FW method. A small-scale forge welding machine has been used to join miniature pipes extracted from a large pipe wall. The welding was performed at three different forging temperatures, i.e., 1300 °C, 1150 °C and 950 °C, in some cases followed by one or two post weld heat treatment cycles. In order to qualify the welds, mechanical and corrosion testing was performed on miniature samples extracted from the welded pipes. In addition, the microstructure of the welds was analysed, and electron probe microanalysis was carried out to control that no oxide film had formed along the weld line. Based on the complete set of experimental results, promising parameters for SAG-FW welding of the API 5CT L80 grade steel are suggested. The most promising procedure includes forging at relative high temperature (1150 °C) followed by rapid cooling and a short temper. This procedure was found to give a weld zone microstructure dominated by tempered martensite with promising mechanical and corrosion properties. The investigation confirmed that small scale forge welding testing is a useful tool in the development of welding parameters for full size SAG-FW welding.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

Evaluation of Tensile Properties Profile of Weld Zone Using Instrumented Indentation

2010 ◽  
Author(s):  
Seung-Kyun Kang ◽  
Young-Cheon Kim ◽  
Chan-Pyoung Park ◽  
Dongil Kwon
Keyword(s):  
Tensile Properties ◽  
Weld Zone ◽  
Indentation Test ◽  
Tensile Tests ◽  
Structural Safety ◽  
Small Scale ◽  
Stress And Strain ◽  
Instrumented Indentation ◽  
Deformation And Fracture ◽  
Instrumented Indentation Test

Understanding the property distribution in the weld zone is very important for structural safety, since deformation and fracture begin at the weakest point. However, conventional tensile tests can measure only average material properties because they require large specimens. Small-scale tests are being extensively researched to remove this limitation, among such tests, instrumented indentation test (IIT) are of great interest because of their simple procedures. Here we describe the evaluation of tensile properties using IIT and a representative stress-strain approach. The representative stressstrain method, introduced in 2008 in ISO/TR29381, directly correlates the stress and strain under the indenter to the true stress and strain of tensile testing by defining representative functions. Using this technique, we successfully estimate the yield strength and tensile strength of structural metallic materials and also obtain profiles of the weld-zone tensile properties.

Demonstration of Intelligent Welding Machine for Polyethylene Pipe

2021 ◽  
Author(s):  
Guangte Xiang ◽  
Yurui Hu ◽  
Sheng Zeng ◽  
Jianfeng Shi ◽  
Jinyang Zheng
Keyword(s):  
Welding Process ◽  
Maximum Temperature ◽  
Welding Parameters ◽  
Welding Time ◽  
Constant Voltage ◽  
Welding Machine ◽  
Reinforced Composite ◽  
Composite Pipe ◽  
The Difference

Abstract Electrofusion (EF) welding is one of the most common connection methods for polyethylene (PE) pipe, as well as thermoplastic pipe and reinforced composite pipe. Conventional EF welding generally adopts constant-voltage welding mode. The welding machine outputs a constant welding voltage to heat the resistance wire within specific welding time. In our previous study, intelligent welding machine was designed to ensure the quality of the EF joint, based on the study of the temperature field in EF joint. In this paper, three experiments were used to show the difference between the intelligent welding machine and traditional welding machine. The intelligent welding machine can actively adjust the welding parameters to ensure the quality of EF joint even it was given the wrong welding voltage and welding time. Compared with the traditional welding machine, the intelligent welding machine can automatically control the maximum temperature and the depth of melting region in EF joint during the welding process, and this method applies for EF joints with various diameters or design welding parameters.

Characterization of Surface Defects Associated with Flash Butt-Welded Pearlitic Rails and their Contribution to Overload and Fatigue Failures

2009 ◽  
Vol 83-86 ◽  
pp. 1262-1269 ◽  
Author(s):  
Mostafa Mousavizade ◽  
Hassan Farhangi
Keyword(s):  
Surface Defects ◽  
Weld Zone ◽  
Welding Process ◽  
Electrical Heating ◽  
Main Concern ◽  
Zone Formation ◽  
Butt Welding ◽  
Fatigue Failures

Generally about 80 percent of railway tracks are welded by flash-butt welding that consists of electrical heating and hydraulic forging. Fracture of rails specially weld zone fractures are of main concern because of potential risk of a catastrophic derailment. In this paper, surface defects associated with flash butt welding process are examined. Metallographic and fractographic studies show various defects can be formed at the surface of weld zone. Formation mechanism of these defects and their contribution to the observed fatigue and overload weld failures are discussed. Fracture mechanics is also utilized to clarify the role of these defects in fatigue and overload failures.

High-Temperture Structural Analysis on a Small-Scale PHE Prototype Considering Mechanical Properties in the Heat-Affected Zone and in the Weld Zone

2012 ◽  
Author(s):  
Kee-Nam Song ◽  
Sung-Deok Hong ◽  
Hong-Yoon Park
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Structural Analysis ◽  
Performance Test ◽  
Weld Zone ◽  
Parent Material ◽  
Small Scale ◽  
Hastelloy X ◽  
Production Of Hydrogen ◽  
Gas Loop

PHE (Process Heat Exchanger) is a key component in transferring the high temperature heat generated from a VHTR (Very High Temperature Reactor) to the chemical reaction for massive production of hydrogen. A performance test on a small-scale PHE prototype made of Hastelloy-X is currently undergoing in a small-scale gas loop at the Korea Atomic Energy Research Institute. Previous researches on the high-temperature structural analysis of the small-scale PHE prototype had been performed using parent material properties over the whole region. In this study, high-temperature elastic structural analysis considering mechanical properties in the weld zone was performed and the analysis result was compared with previous researches.

Establishment of Testing Methodology for Forge Welded Tubular Products

2012 ◽  
Author(s):  
Ganesan S. Marimuthu ◽  
Per Thomas Moe ◽  
Bjarne Salberg ◽  
Jan Inge Audestad
Keyword(s):  
Material Flow ◽  
Large Scale ◽  
Flow Behavior ◽  
Treatment Options ◽  
Full Scale ◽  
International Standards ◽  
Small Scale ◽  
Test Plan ◽  
Welding Machine

A state-of-the-art small-scale solid state forge welding machine has been fabricated for checking weldability by Shielded Active Gas Forge Welding (SAG-FW) of tubular products applicable predominantly for, but not limited to offshore Industries. Effective, fast and inexpensive welding and testing of joints make this small-scale method suitable for evaluating weldability of a material before starting regular qualification and fabrication in a full-scale welding machine normally located in spool base or offshore. The small-scale machine provides a complete package for pre-qualification studies, including assessment of welding conditions, material flow behavior, heat treatment options. However, there are considerable challenges relating to application of international standards of testing as well as interpretation and use of results in the context of large-scale welding. In this paper results from small-scale welding and weld characterization of an API 5L X65 quality are presented. First, a detailed test plan for analyzing the weld is outlined. This procedure is subsequently applied for checking the welds to be produced in the full-scale machine. Short-comings in using the small-scale process as well as the possible remedies are discussed in detail.

scholarly journals Effect of the t8/5 Cooling Time on the Properties of S960MC Steel in the HAZ of Welded Joints Evaluated by Thermal Physical Simulation

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 229 ◽  
Author(s):  
Miloš Mičian ◽  
Daniel Harmaniak ◽  
František Nový ◽  
Jerzy Winczek ◽  
Jaromír Moravec ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Welded Joints ◽  
Physical Simulation ◽  
Weld Zone ◽  
Cooling Time ◽  
Temperature Cycle ◽  
Welding Parameters ◽  
Hardness Profile ◽  
Specimen Thickness ◽  
Soft Zone

The heat input into the material during welding significantly affects the properties of high-strength steels in the near-weld zone. A zone of hardness decrease forms, which is called the soft zone. The width of the soft zone also depends on the cooling time t8/5. An investigation of the influence of welding parameters on the resulting properties of welded joints can be performed by thermal physical simulation. In this study, the effect of the cooling rate on the mechanical properties of the heat-affected zone of the steel S960MC with a thickness of 3 mm was investigated. Thermal physical simulation was performed on a Gleeble 3500. Three levels of cooling time were used, which were determined from the reference temperature cycle obtained by metal active gas welding (MAG). A tensile test, hardness measurement, impact test with fracture surface evaluation, and microstructural evaluation were performed to investigate the modified specimen thickness. The shortest time t8/5 = 7 s did not provide tensile and yield strength at the minimum required value. The absorbed energy after recalculation to the standard sample size of 10 × 10 mm was above the 27 J limit at −40 °C. The hardness profile also depended on the cooling rate and always had a softening zone.

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