scholarly journals Microstructural Evaluation of the High-Frequency Induction Welded Joints of Low Carbon Steel Pipes

2021 ◽  
Vol 21 (4) ◽  
pp. 19-33
Author(s):  
Adam Bunsch ◽  
Janusz Krawczyk ◽  
Piotr Matusiewicz

Abstract The work presents the results of research on the structure of welded joints in the area of heat affected zone (HAZ). Based on precisely performed metallographic tests, the contribution of individual structural components in the area of welds of pipes welded with the induction method was assessed. The volume fraction of individual structural components in various areas of the heat affected zone, the size of the grain formed in the welding process, as well as its shape coefficients were determined. On the basis of metallographic observations, an attempt was made to describe the course of the pressure induction welding process, taking into account the structural changes, phase changes and the recovering and recrystallization processes taking place in this process.

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5059
Author(s):  
Michail Nikolaevich Brykov ◽  
Ivan Petryshynets ◽  
Miroslav Džupon ◽  
Yuriy Anatolievich Kalinin ◽  
Vasily Georgievich Efremenko ◽  
...  

The purpose of the research was to obtain an arc welded joint of a preliminary quenched high-carbon wear resistant steel without losing the structure that is previously obtained by heat treatment. 120Mn3Si2 steel was chosen for experiments due to its good resistance to mechanical wear. The fast cooling of welding joints in water was carried out right after welding. The major conclusion is that the soft austenitic layer appears in the vicinity of the fusion line as a result of the fast cooling of the welding joint. The microstructure of the heat affected zone of quenched 120Mn3Si2 steel after welding with rapid cooling in water consists of several subzones. The first one is a purely austenitic subzone, followed by austenite + martensite microstructure, and finally, an almost fully martensitic subzone. The rest of the heat affected zone is tempered material that is heated during welding below A1 critical temperature. ISO 4136 tensile tests were carried out for the welded joints of 120Mn3Si2 steel and 09Mn2Si low carbon steel (ASTM A516, DIN13Mn6 equivalent) after welding with fast cooling in water. The tests showed that welded joints are stronger than the quenched 120Mn3Si2 steel itself. The results of work can be used in industries where the severe mechanical wear of machine parts is a challenge.


2015 ◽  
Vol 788 ◽  
pp. 218-224
Author(s):  
Aelita Nikulina ◽  
Vadim Yu. Skeeba ◽  
Alexandra Chevakinskaya ◽  
Pavel Komarov

This paper shows the results of solving a 3D problem to define types of structures and tensions which can appear during the butt contact welding process of dissimilar steels through low carbon steel inserts. The finite element method to calculate welded structures was used. The thickness of inserts was the main variable parameter. According to the results of numerical simulation using inserts can increase the reliability of welded joints between pearlitic high-carbon steel and austenitic chromium-nickel steel. The best result was obtained by using an insert with a thickness less than 20 mm. Structural studies of the welded joints between high-carbon steel and chromium-nickel steel through low-carbon inserts confirm the results of mathematical modeling.


2022 ◽  
Vol 26 (1) ◽  
pp. 79-86
Author(s):  
Hussain Hayyal ◽  
◽  
Nadhim M. Faleh ◽  

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%..


Author(s):  
Anjas Nurcahyo Kurniawan ◽  
Suharno Suharno ◽  
Indah Widiastuti

<p>The purpose of this research is to investigate the influence of groove weld type on the welding joint to the physical and mechanical characteristic using the Shielded Metal Arc Welding (SMAW) method. The welding process causes the around metal has thermal cycles and then resulting metallurgical changes, deformations and thermal stresses. Because of these structural changes, the mechanical characteristic will change as well.</p><p>This research use experimental method that is researcher doing butt joint welding with X, V and ½ V groove weld type by using low carbon steel SS400 with carbon content 0,1% then testing micro structure, hardness and tensile strength.</p>Based on the results of the study, it can be concluded that the results of microstructure test showed improvement of acicular structure of ferrite and pearlite after welding. In raw material, the grain boundary structure of ferrite is evenly distributed. Hardness values on welding results indicate a different level of violence. The specimen with V type has the highest hardness of 248,6 VHN, then the specimen with ½ V form is 233,7 VHN and the specimen with the X type is 228,6 VHN while the raw material has hardness value 200,58 VHN. The value of tensile strength on the welding results indicates a difference. The specimen with the V type have the highest tensile strength level of 430,97 MPa and strain 18,11% then the ½ V type is 419,93 MPa and strain 15,52% followed by the X type with the average of tensile strength 414,88 MPa and strain 14,92% and on raw material has a tensile strength value 401,94 MPa and strain 13,26%. This study shows that welding using variations of groove weld type changes the microstructure and affects the hardness and tensile strength of SS400 Steel


2014 ◽  
Vol 2 (1) ◽  
pp. 59-76
Author(s):  
Abdullah Daie'e Assi

This research deals with the choice of the suitable filler metal to weld the similar and dissimilar metals (Low carbon steel type A516 & Austenitic stainless steel type 316L) under constant conditions such as, plate thickness (6 mm), voltage (78 v), current (120 A), straight polarity. This research deals with three major parts. The first parts Four types of electrodes were used for welding of dissimilar metals (C.St A516 And St.St 316L) two from mild steel (E7018, E6013) and other two from austenitic stainless steel (E309L, E308L) various inspection were carried out include (Visual T., X-ray T., δ- Ferrite phase T., and Microstructures T.) and mechanical testing include (tensile T., bending T. and micro hardness T.) The second parts done by used the same parameters to welding similar metals from (C.St A516) Or (St.St 316L). The third parts deals with welding of dissimilar weldments (C.St And St.St) by two processes, gas tungsten are welding (GTAW) and shielded metal are welding (SMAW).        The results indicated that the spread of carbon from low carbon steel to the welding zone in the case of welding stainless steel elect pole (E309L) led to Configuration Carbides and then high hardness the link to high values ​​compared with the base metal. In most similar weldments showed hardness of the welding area is  higher than the hardness of the base metal. The electrode (E309L) is the most suitable to welding dissimilar metals from (C.St A516 With St.St 316L). The results also showed that the method of welding (GTAW) were better than the method of welding (SMAW) in dissimilar welded joints (St.St 316L with C.St A516) in terms of irregular shape and integrity of the welding defects, as well as characterized this weldments the high-lift and resistance ductility good when using the welding conditions are similar.


Author(s):  
Aleksander Siwek

AbstractThis paper presents a numerical model of the laser welding of steel, taking into account the heat and mass flows, as well as thermal effects associated with phase transformations. It was assumed that the heat source is a laser with a symmetrical power distribution of the TEM10 beam in two welding condition variants: a stationary heat source and a source moving at a constant speed along the sample. After reaching the melting temperature, the movement of the liquid phase was forced by the Marangoni effect acting on the surface of the welding pool. For the laser power applied, the surface of the welding pool was assumed to be flat. It was proposed an algorithm for the forecasting of the phase changes during heating and cooling. Diffusive phase transformations during cooling were modelled using Johnson-Mehl-Avrami-Kolmogorov (JMAK) equations. Diffusionless transformations occurring when cooling rates exceed the critical ones were modelled using Koistinen-Marburger (KM) equations. Calculations were made for a rectangular sample welded in air and cooled spontaneously in the atmosphere. The boundary conditions were simulated assuming a constant coefficient of heat exchange and radiation to the environment. The start and end time of the changes occurring in the cooling phase were calculated based on the average cooling rate in the temperature range 800–500°C (v8/5). The model was tested for the test material: S355J2 steel.


2017 ◽  
Vol 17 (2) ◽  
pp. 29-40 ◽  
Author(s):  
M. A. Tashkandi ◽  
J. A. Al-Jarrah ◽  
M. Ibrahim

AbstractThe main aim of this investigation is to produce a welding joint of higher strength than that of base metals. Composite welded joints were produced by friction stir welding process. 6061 aluminum alloy was used as a base metal and alumina particles added to welding zone to form metal matrix composites. The volume fraction of alumina particles incorporated in this study were 2, 4, 6, 8 and 10 vol% were added on both sides of welding line. Also, the alumina particles were pre-mixed with magnesium particles prior being added to the welding zone. Magnesium particles were used to enhance the bonding between the alumina particles and the matrix of 6061 aluminum alloy. Friction stir welded joints containing alumina particles were successfully obtained and it was observed that the strength of these joints was better than that of base metal. Experimental results showed that incorporating volume fraction of alumina particles up to 6 vol% into the welding zone led to higher strength of the composite welded joints as compared to plain welded joints.


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.


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.


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