scholarly journals Hybrid Welding (Laser–Electric Arc MAG) of High Yield Point Steel S960QL

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5447
Author(s):  
Michał Urbańczyk ◽  
Janusz Adamiec
Keyword(s):  
Welded Joints ◽  
Base Material ◽  
Welding Process ◽  
Electric Arc ◽  
Coarse Grained ◽  
High Yield ◽  
Quality Level ◽  
Hybrid Welding ◽  
Plastic Properties ◽  
Welding Thermal Cycle

The article discusses the effect of the hybrid-welding process (laser–electric arc MAG Metal Active Gas) on the structure and properties of butt joints (having various thicknesses, i.e., 5 mm and 7 mm) made of steel S960QL. Welding tests were performed in the flat position (PA) and in the horizontal position (PC). Joints made of steel S960QL in the above-presented configuration are present in elements of crane structures (e.g., telescopic crane jibs). The welding tests involved the use of the G Mn4Ni1.5CrMo solid electrode wire and the Ar+18% CO2 shielding gas mixture (M21) (used in the MAG method). Non-destructive visual and radiographic tests did not reveal the presence of any welding imperfections in the joints. The welded joints obtained in the tests represented quality level B in accordance with the requirements of the ISO 12932 standard. Microscopic metallographic tests revealed that the heat-affected zone (HAZ) contained the coarse-grained martensitic structure resulting from the effect of the complex welding thermal cycle on the microstructure of the joints. Destructive tests revealed that the joints were characterised by tensile strength similar to that of the base material. The hybrid welding (laser–MAG) of steel S960QL enabled the obtainment of joints characterised by favourable plastic properties and impact energy exceeding 27 J. The tests revealed the possibility of making hybrid-welded joints satisfying the quality-related requirements specified in the ISO 15614-14 standard.

scholarly journals Assessment of the Makeability of T-welded Joints in 10 mm Thick TMCP Steel Using Laser Beam

2018 ◽  
Author(s):  
Jacek Górka
Keyword(s):  
Laser Beam ◽  
Welded Joints ◽  
Base Material ◽  
Scanning Transmission Electron Microscope ◽  
High Yield ◽  
Deep Penetration ◽  
Quality Level ◽  
Plastic Properties ◽  
Thin Foils ◽  
Scanning Transmission

The article presents tests aimed to verify the possibility of making T-joints in TMCP steel using laser. The tests involved the use of 10 mm thick high yield point steel S700MC obtained in an industrial manufacturing process. The joints made in the tests were single and double-sided. Subsequent non-destructive tests revealed that the joints obtained in the tests represented quality level B in accordance with PN-EN ISO 13919-1. Single-sided welding performed using the laser beam having a power of 11 kW enabled the obtainment of 8 mm deep penetration without visibly deforming the web of the joint. The double-sided welded joints were characterised by proper geometry and the presence of gas pores in the welds not compromising the requirements of quality level B (strict requirements). The weld structure was bainitic-ferritic. The weld hardness was by approximately 60 HV1 higher than that of the base material (280 HV1). The HAZ area was slightly softer than the base material. The tests of thin foils performed using a high-resolution scanning transmission electron microscope revealed that, during welding, an increase in the content of the base material in the weld was accompanied by an increase in contents of alloying microagents Ti and Nb, particularly near the fusion line. The above-named alloying microagents, in the form of fine-dispersive (Ti,Nb)(C,N) type precipitates, could reduce plastic properties of joints.

scholarly journals Assessment of the Effect of Laser Welding on the Properties and Structure of TMCP Steel Butt Joints

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1312 ◽  
Author(s):  
Jacek Górka
Keyword(s):  
Laser Beam ◽  
Welded Joints ◽  
Research Work ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Tensile Tests ◽  
Carbon Equivalent ◽  
Quality Level ◽  
Butt Joints ◽  
Plastic Properties

The research work and related tests aimed to identify the effect of filler metal-free laser beam welding on the structure and properties of butt joints made of steel 700MC subjected to the TMCP (thermo-mechanically controlled processed) process. The tests involved 10-mm thick welded joints and a welding linear energy of 4 kJ/mm and 5 kJ/mm. The inert gas shielded welding process was performed in the flat position (PA) and horizontal position (PC). Non-destructive testing enabled classification of the tested welded joints as representing the quality level B in accordance with the requirements set out in standard 13919-1. Destructive tests revealed that the tensile strength of the joints was 5% lower than S700MC steel. The results of tensile tests and changes in structure were referred to joints made using the MAG (Metal Active Gas) method. The tests of thin films performed using a high-resolution scanning transmission electron microscope revealed that, during laser beam welding, an increase in dilution was accompanied by an increase in the content of alloying microadditions titanium and niobium, particularly in the fusion area. A significant content of hardening phases in the welded joint during cooling led to significant precipitation hardening by fine-dispersive (Ti,Nb)(C,N) type precipitates being of several nanometres in size, which, in turn, resulted in the reduction of plastic properties. An increase in the concentration of elements responsible for steel hardening, i.e., Ti and Nb, also contributed to reducing the weld toughness below the acceptable value, which amounts to 25 J/cm2. In cases of S700MC, the analysis of the phase transformation of austenite exposed to welding thermal cycles and the value of carbon equivalent cannot be the only factors taken into consideration when assessing weldability.

scholarly journals Weldability of Thermomechanically Treated Steels Having a High Yield Point

2015 ◽  
Vol 60 (1) ◽  
pp. 469-475 ◽  
Author(s):  
J. Górka
Keyword(s):  
Yield Point ◽  
Welded Joints ◽  
Welding Process ◽  
High Yield ◽  
Plastic Properties ◽  
Nucleation Effect ◽  
The Matrix ◽  
Finely Disperse ◽  
Strengthening Phases

Abstract The article concerns the issue of weldability of S700MC steel, treated thermo-mechanically, with high yield point. The weakest area of welded joints of this steel is a high - temperature coarse heat affected zone (HAZ) in which due to the nucleation effect of the dissolved phases, strengthening the matrix and their subsequent uncontrolled separation precipitation in the form of finely disperse and rapid decrease impact strength is observed. Performed arc welding tests here have shown that in order to ensure high quality of welded joints, it is necessary to limit the welding linear heat input. During the welding process of S700MC steel, it is not recommended to use pre heating before the welding process and heat treatment after welding, and the number of repairs should be kept to a minimum, because it leads to a reduction of strength and plastic properties in the HAZ area, as a result of aging processes, dissolution of strengthening phases in the matrix and their subsequent uncontrolled precipitation during cooling.

scholarly journals Electron Beam Welding of TMCP steel S700MC

2020 ◽  
pp. 17-23
Author(s):  
Jacek Górka ◽  
Sylwester Błacha ◽  
Dawid Zagrobelny
Keyword(s):  
Electron Beam ◽  
Electron Beam Welding ◽  
Base Material ◽  
Welding Process ◽  
Tensile Tests ◽  
Quality Level ◽  
Plastic Properties ◽  
Hardness Tests ◽  
Static Tensile ◽  
Made In

The article discusses tests aimed to determine the effect of electron beam welding on the properties of butt welded joints made in 10 mm thick TMCP steel S700MC. The welding process was performed in the flat position (PA) using an XW150:30/756 welding and surface processing machine (Cambridge Vacuum Engineering). The joints obtained in the tests were subjected to non-destructive tests including visual tests and magnetic particle tests. The joints were also subjected to destructive tests including static tensile tests, bend tests, toughness tests (performed at a temperature of -30°C), hardness tests as well as macro and microscopic metallographic tests. The destructive tests revealed that the joint represented quality level B in accordance with the PN EN ISO 13919-1 standard. The analysis of the destructive test results related to the electron beam butt welded joint (made in steel S700MC) revealed its high mechanical and plastic properties. The toughness tests revealed a decrease in toughness in the HAZ (27 J/cm2) in comparison with that of the base material (50 J/cm2). In addition, the hardness of the HAZ and of the weld increased up to approximately 330 HV; the hardness of the base material amounted to 280 HV.

Characterization of Local Deformation in Welded Joints Using a Combined Experimental and Numerical Approach

2014 ◽  
Vol 627 ◽  
pp. 241-244 ◽  
Author(s):  
Pawel Kucharczyk ◽  
Sebastian Münstermann
Keyword(s):  
Chemical Composition ◽  
Weld Metal ◽  
Welded Joints ◽  
Base Material ◽  
Welding Process ◽  
Numerical Approach ◽  
Geometrical Model ◽  
Local Deformation ◽  
Heat Treated ◽  
Welded Structure

The microstructure of welded joints differs significantly from that of the base material, what changes their mechanical properties and influences fatigue life. The aim of this work was the investigation of the local deformation field within a butt joint made of 10 mm thick structural steel S355. However, a direct sampling even of the weld metal was impossible due to small dimensions of butt joints. Therefore, the following procedure was utilized in order to manufacture big samples of the microstructure identical to that of the local weldment areas.A geometrical model of the welded structure describing the relevant areas e.g. weld metal, heat-affected zone was established. It was based on the results of the metallographic investigations, hardness mapping and electron-probe-micro-analysis of the local chemical composition. The welding process was numerically simulated using SYSWELD program to estimate the time-temperature-transition (TTT) curves for each identified area. The parameters of the heat input source were calibrated. Afterwards, the material of the defined chemical composition was heat-treated according to the TTT curves. For the validation purpose the heat-treated work pieces were evaluated in terms of microstructure and hardness distribution. Finally, the up-scaled samples of the respective bulk microstructure were manufactured and investigated in monotonic tests.

Austenite Decomposition Kinetics in Laser-Hybrid Welding of Steel of Strength Class K52

2019 ◽  
Vol 946 ◽  
pp. 950-955 ◽  
Author(s):  
A.I. Romantsov ◽  
M.A. Fedorov ◽  
D.G. Lodkov
Keyword(s):  
Welded Joints ◽  
Strength Class ◽  
Defect Formation ◽  
Welding Process ◽  
Decomposition Kinetics ◽  
Hybrid Welding ◽  
Austenite Decomposition ◽  
Laser Hybrid Welding ◽  
Laser Hybrid ◽  
The Impact

A modern technology for joining materials welding is commonly used in various industries. It is a process of interaction of thermal, mechanical and metallurgical properties and behaviors. Complex phenomena, such as solidification, microstructural changes and defect formation, have a great impact on the quality of welded joints. This article presents the results of studying the features of the austenite decomposition kinetics in the application of laser-hybrid welding technology, in a combination with multi-arc automatic submerged arc welding. The cooling rates are determined, affecting the change in properties of HAZ of welded joints on pipe steel of strength class K52. Using the dilatometric method, studies were conducted and thermo-kinetic and structural diagrams were constructed. Analysis of diagrams and microstructures showed that, as a result of the impact of the laser-hybrid welding process in the area of HAZ, the decomposition of austenite occurs mainly in the martensitic zone, followed by the formation of a bainite-perlite structure, due to recrystallization from the heat generated by the facing seams.

scholarly journals Forming and Properties of Friction Stir Welding Process for Dissimilar Mg Alloy

2015 ◽  
Vol 9 (1) ◽  
pp. 859-864
Author(s):  
Tielong Li ◽  
Zhenshan Wang
Keyword(s):  
Magnesium Alloy ◽  
Process Parameters ◽  
Welded Joints ◽  
Defect Formation ◽  
Base Material ◽  
Welding Process ◽  
Fracture Initiation ◽  
Line Defect ◽  
Influence Of Process Parameters ◽  
Friction Stir

For hot extrusions of magnesium alloy sheets, Dissimilar AZ80 and AZ31 were used, in which AZ80 was placed on advancing side and AZ31 on retreating side, using friction stir butt welding with different process parameters. Some defect-free welded joints with good weld surfaces could be obtained with some suitable welding conditions. The maximum tensile strength of welded joint which is 225.5 MPa can reach 98% that of the AZ31 base material. Influence of process parameters on defects, weld shaping and mechanical property were discussed systematically. And the microstructure of different zones was compared. The fracture of the welded joints takes place at the junction of mechanical heat affected zone and nugget zone in AZ31 magnesium alloy set retreating side, since existing difference in metallographic structure of alloy diversely suffered by heat, pressure and depositing impurities. Fracture initiation site may be the P line defect which should be eliminated, and the P line defect formation was analyzed.

scholarly journals Comparative Study on Welding Characteristics of Laser-CMT and Plasma-CMT Hybrid Welded AA6082-T6 Aluminum Alloy Butt Joints

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3300 ◽  
Author(s):  
Zhibin Xin ◽  
Zhibin Yang ◽  
Han Zhao ◽  
Yuxin Chen
Keyword(s):  
Aluminum Alloy ◽  
Comparative Study ◽  
Welded Joints ◽  
High Speed ◽  
Shear Fracture ◽  
Welding Process ◽  
Hybrid Welding ◽  
Micro Hardness ◽  
Butt Joints ◽  
Promising Alternative

Laser-CMT (Cold Metal Transfer) and plasma-CMT hybrid welding are two promising alternative joining technologies for traditional Metal-Inert-Gas (MIG) welding of the aluminum alloy joints in the high speed trains manufacturing industry. In this work, a comparative study on the weld formation, microstructure, micro-hardness, and mechanical properties of the butt joints in the two welding methods was conducted. The results indicate that the overall quality of the laser-CMT and plasma-CMT welds were good, especially of the laser-CMT hybrid weld, and the laser-CMT hybrid welding process needed a lower heat input. The width of the partially melted zone of the laser-CMT hybrid weld was narrower than that in the plasma-CMT hybrid weld. Micro-hardness test results show that two distinct softening regions were identified in the heat affected zone, and the micro-hardness values of each zone in the laser-CMT hybrid weld were lower than that in the plasma-CMT hybrid weld. The tensile strength of the laser-CMT hybrid welded joints was higher than that of the plasma-CMT hybrid welded joints, which could reach up to 79.4% and 73.7% of the base materials, respectively. All the fractures occurred in the softening region and exhibited a ductile shear fracture with a shear angle of approximately 45°. The fractographs manifested that the laser-CMT and plasma-CMT hybrid welded joints presented ductile fracture and ductile-brittle fracture features, respectively.

scholarly journals EFFECT OF WELDING PROCESS PARAMETERS ON TENSILE OF LOW CARBON STEEL 283 G.C

2022 ◽  
Vol 26 (1) ◽  
pp. 79-86
Author(s):  
Hussain Hayyal ◽  
◽  
Nadhim M. Faleh ◽  
Keyword(s):  
Carbon Steel ◽  
Tensile Stress ◽  
Welded Joints ◽  
Arc Welding ◽  
Low Carbon Steel ◽  
Base Material ◽  
Welding Process ◽  
Welding Current ◽  
Low Carbon ◽  
Tungsten Electrode

In this study, three welding methods are used. The purpose to investigation the effects of SMAW, SAW, and gas tungsten arc welding (GTAW) on the tensile stress of low carbon steel conforming to ASTM 283 c. 8mm thick plates are used as base material for butt welded joints. The tensile properties of the welded joints were evaluated and the results were compared by experts using the Taguchi method to design three levels of each parameter (current, voltage and displacement speed). From this research, it is found that compared to metal shielded arc welding and submerged arc welding, the pulling effect of the gas shielded welding joint of the tungsten electrode is the best. This is mainly due to the presence of The results of using analysis of variance (ANOVA) to estimate important parameters show that welding current and speed of the weld have a significant effect on tensile stress .the experimental results are in agreement with predicted results, and the maximum error is 3%..

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