Droplet Transfer and Microstructure of Q235 Steel Thick Plate Using CO2 Welding with Additional Longitudinal Magnetic Field Controlling

2010 ◽  
Vol 102-104 ◽  
pp. 451-454
Author(s):  
Qian Luo ◽  
Duan Min Lu ◽  
Jian Luo

In this paper, a new welding experiment is studied by applying an additional longitudinal electromagnetic field to CO2 welding process (abbr. LEM-CO2 welding).The characteristics of droplet transfer, macrostructure and microstructure are compared between LEM- CO2 welding and general CO2 welding on Q235 low carbon steel thick plate joint. The research results shows that, an additional longitudinal magnetic field can have a significant effect on properties of the droplet transfer in CO2 welding, the frequency and stability of the droplet transfer in LEM-CO2 welding are improved. The grains of welding seam are refined and welding joints has a higher quality. So the additional longitudinal magnetic field is a very simple and effective method to improve the properties of CO2 welding thick plate joint.

Teknomekanik ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 56-61
Author(s):  
Zetri Firmanda ◽  
Abdul Aziz ◽  
Bulkia Rahim

The purpose of this study was to determine the effect of alternating current (AC) and direct current (DC) on the bend testing results of low carbon steel welding joints. The results of this study are expected to determine the cracks that occur from the root bend and face bend testings in the AC and DC welding process. This study used experimental method, where the research was done by giving AC and direct polarity DC (DC-) SMAW welding treatments. The material used in this research was low carbon steel plate DIN 17100 Grade ST 44, thickness 10 with E7016 electrode type. The process of welding joints used a single V seam, strong current of 90A, and the welding position of 1G. The testing of welding joints was carried out by bend testing using the standard acceptance of AWS D1.1 root bend and face bend testing results. The results of the bend testing showed that the AC welding root bend test specimen held no cracks while the DC welding root bend test held cracks with incompelete penetration and open crack defects. On the contrary, the AC welding face bend test had open crack defects and in the DC welding face bend test was found a crack. Thus, there was a difference in the crack resistance of the welding joint from the types of current used through the root bend test and face bend test. Therefore, it can be summarized that AC welding is better for root welding and DC welding is good for capping welding.


2012 ◽  
Vol 538-541 ◽  
pp. 1447-1450 ◽  
Author(s):  
Shu Yuan Jiang ◽  
Xiao Wei Wang ◽  
Huan Ming Chen ◽  
Pin Liu

Aiming at the welding arc can act with the magnetic field, has electrical quasi-neutral and electrical conductivity. This paper introduced an adscititious longitudinal magnetic field to control the CO2 welding process and used the Hanover Welding Quality Analyzer to acquire the real-time welding signal. Meanwhile, the short circuit behavior of CO2 welding under the adscititious longitudinal magnetic field, was monitored with the High-speed Photography System. The results show that when the excitation current in an optimal range, the welding current decay and the frequency of short circuit transition is uniform and faster, smaller droplet size and the welding process is more stability than welding without adscititious magnetic field.


2010 ◽  
Vol 154-155 ◽  
pp. 1271-1274
Author(s):  
Yun Hai Su ◽  
Zheng Jun Liu ◽  
Ming Su

In order to systematically study the influence of surfacing current and magnetic field current on hardness and wear resistance of surfacing layer, longitudinal DC magnetic field was applied during plasma arc surfacing Co-based alloy on low-carbon steel. The hardness, wear resistance, microstructure and phase constitution of the surfacing layer were investigated through the tests of hardness, wear, SEM and XRD analysis. The results show that the surfacing current and magnetic field current must be matched properly to achieve the optimal properties of surfacing layer. The optimal values are obtained when the surfacing current is 160A and the magnetic field current is 3A, where the hardness is 43.7 HRC and the wear loss is 0.5493g. The proper electromagnetic stirring induced by electromagnetic field can not only refine the microstructure but also improve the hardness and wear resistance of the surfacing layer.


With the advancement of welding techniques, Arc-welding is one of the most commonly and widely used welding technique for variety of purposes. The underside of welding to be performed makes the molten pool going downward because of gravity vector pulling affects the molten pool. The main purpose of this study is to study how the molten of electrode produced reduce on going downward and produce a good root fusion in overhead position of welding in single V-butt joint with the help of magnetic field on the workpiece. The study of magnet characteristic which includes thebehaviour of molten pool toward magnetic field, the macrostructure and microstructure and its strength should be carried out. Each magnet strength has their own characteristics that affects toward weldment on base metal.As a result, it can be concluded that having a magnetic field applies on base metal A36 low carbon steel may reduce the molten pool from going downward. The selection of a correct magnet strength and welding process may produce good and quality weldment especially in terms of its weld properties and geometry.


2012 ◽  
Vol 557-559 ◽  
pp. 1742-1746 ◽  
Author(s):  
Zheng Jun Liu ◽  
Duo Liu ◽  
Chang Jun Liu

plasma arc sufacing; magnetic field style ;Ni-based alloy;microstructure and properties Abstract. The Ni60 alloy was overlaid on low carbon steel by plasma arc surfacing with Longitudinal magnetic field or transverse magnetic field. The magnetic field current and surfacing current could been changed during surfacing. After plasma arc surfacing with magnetic field, the XRD, wear loss tes, micro-hardness test were used to analyze the effect of magnetic field style on properties of overlay deposit. The acting mechanism of magnetic field style and parameters on properties and microstructure of overlay deposit was researched. The results indicate that longitudinal magnetic field and transverse magnetic field all can improve the properties of overlay deposit, but give little effectives intervention to the process parameters. The active effect of transverse magnetic field is better than longitudinal magnetic field because of transverse magnetic field can make the microstructure finer, component more uniform.


2021 ◽  
Vol 100 (01) ◽  
pp. 1-12
Author(s):  
JIANG YU ◽  
◽  
HONGTAO ZHANG ◽  
PENG HE ◽  
XIAO YANG ◽  
...  

Low-carbon steel Q235B was successfully joined by plasma-pulsed gas metal arc welding (plasma-GMAW-P) with an external magnetic field. The arc profile, temperature field, electrical signal, microstructure, and mechanical properties of this method were analyzed. The results indicated that the coupling degree of the two arcs increased with the strengthening of the magnetic field current. However, when the magnetic field current was greater than 1 A, the arc pro-file changed slightly with the increase of the magnetic field current. Fixed on the magnetic field current, the coupling degree first increased and then decreased with the increase of the plasma welding current, GMAW-P welding current, plasma gas flow rate, and nozzle height, respectively. The maximum temperature had no obvious influence on joint penetration at different magnetic field cur-rents. However, the average temperature had an inverse effect on joint penetration at different magnetic field currents. The weld fusion zone joint tensile test results showed that the ratio of depth to width increased with the application of magnetic field currents. Moreover, tensile strength on the upper and lower part of the tensile samples were 521 and 488 MPa, respectively, which were 4.6% and 3.2% higher than those without the magnetic field. The microhardness of the weld joints was higher than that without the magnetic field.


2011 ◽  
Vol 189-193 ◽  
pp. 993-996 ◽  
Author(s):  
Sheng Zhu ◽  
Qi Wei Wang ◽  
Feng Liang Yin ◽  
Yuan Yuan Liang ◽  
Xiao Ming Wang

The stress and motion state of droplet in MIG welding with alternating longitudinal magnetic field were analyzed, and the impact of alternating longitudinal magnetic field on the droplet transfer were studied by high-speed video camera. The results show that the droplet is spherical approximately and transfer to molten pool along the welding wire axis without external longitudinal magnetic field. When alternating longitudinal magnetic field was introduced into welding process, the droplet rotate around the welding wire clockwise and counter-clockwise alternately. Shape of droplet became flat and direction of transfer deviated from the welding wire axis under the action of magnetic field. As the exciting current increased, extent of deviation from the wire axis increases. When the exciting current is too large (I >20A), extent of deviation is too large and droplet are disintegrated into several small droplet during the transition. So droplet can not transfer into molten pool successfully and the bead can’t be formed.


2021 ◽  
pp. 85-91
Author(s):  
А.С. Угловский ◽  
И.М. Соцкая ◽  
Е.В. Шешунова

Цель рассмотрения численного метода заключалась в получении подробных данных, позволяющих оценить проведение сварочного процесса: изменение объёма сварного шва, радиуса сварного шва, радиуса зоны термического влияния. При проведении моделирования авторами выведены зависимости параметров точечной сварки низкоуглеродистой стали толщиной до 3,2 мм. Данные зависимости будут определять качество сварных швов. Соответствующее сочетание параметров точечной сварки обеспечит прочное соединение и хорошее качество сварки. The purpose of the numerical method consideration was to obtain detailed data allowing evaluating the performance of the welding process: changing the volume of the weld, the radius of the weld, the radius of the weld-affected zone. During the simulation the authors have derived dependencies of the parameters of spot welding of low-carbon steel up to 3.2 mm thick. These dependencies will determine the quality of the welds. The correct combination of spot welding parameters will ensure a firm joint and good welding quality.


2019 ◽  
Vol 13 (1) ◽  
pp. 4415-4433
Author(s):  
I. B. Owunna ◽  
A. E. Ikpe

Induced residual stresses on AISI 1020 low carbon steel plate during Tungsten Inert Gas (TIG) welding process was evaluated in this study using experimental and Finite Element Method (FEM). The temperature range measured from the welding experimentation was 251°C-423°C, while the temperature range measured from the FEM was 230°C-563°C; whereas, the residual stress range measured from the welding experimentation was 144MPa-402Mpa, while the residual range measured from the FEM was 233-477MPa respectively. Comparing the temperature and stress results obtained from both methods, it was observed that the range of temperature and residual stresses measured were not exactly the same due to the principles at which both methods operate but disparities between the methods were not outrageous. However, these values can be fed back to optimization tools to obtain optimal parameters for best practices.  Results of the induced stress distribution was created from a static study where the thermal results were used as loading conditions and it was observed that the temperature increased as the von-Mises stress increased, indicating that induced stresses in welded component may hamper the longevity of such component in service condition. Hence, post-weld heat treatment is imperative in order to stress relieve metals after welding operation and improve their service life.


2014 ◽  
Vol 680 ◽  
pp. 97-101
Author(s):  
Hai Bin Huang ◽  
Jian Chun Liu ◽  
Xiao Long Ke ◽  
Xiao Hui Lin

In order to weld the skin and skeleton of bus roof, it analysis the welding process of bus Outer Roof-panels , and specify the weld area and solder joint distance of outer roof-panel firstly , then built a single-sided double-point resistance welding experiment platform for bus outer roof-panels, the platform consists of guide、gantry、gantry moving mechanism、 pneumatic torch、electrode support mechanism、transformers、torch lateral movement organizations and torch longitudinal movement phenomenon . it set the unevenness of the skin and the skeleton as 1mm, single-sided double-point resistance welding experiment was conducted on the welding experiment platform. The experimental results of welding area visual examination and tear experiments indicate that welding heat will penetrate the skeleton when the welding current is greater than 11.0KA;the welding Reliability of galvanized steel is better than low carbon steel.


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