Wyniki wyszukiwania - BazTech

1

Consequences of using overlays on welded joints

Wojsyk Kwiryn, Nawrocki Jerzy

Welding Technology Review

|

2023

|

R. 95

78--86

EN

The article refers to an earlier publication regarding "reinforcing" overlays on welded joints. In this context, the main principles of designing welded structures were reminded. To verify the principle of not using overlays on the welds, an FEM simulation of such a model was performed. Simulation proved that weld overlays used in plate girder structures are ballast, because they do not participate in stress transfer when tensile is dominant. In addition, they generate a stress concentration in the corner of the pad, which greatly reduces the time to fatigue failure of the structure. A list of the recommendations, requirements for the correct use of overlays on welded joints is given.

2

Impact analysis of micro-jet cooling for stress concentration in a crane bumper during a collision

Haniszewski Tomasz, Węgrzyn Tomasz, Szczucka-Lasota Bożena

Transport Problems

|

2023

|

T. 18, z. 2

97--110

EN

In the structure of crane bumpers, there is a need to join various types of steel. Usually, low-alloy steel structures are used for this purpose, which can be represented by S355J2 steel. The tensile strength of S355J2 low-alloy steel is slightly below 600 MPa, and the tensile strength of S355J2 steel is at the high level of 200 J at ambient temperature. The impact strength of this steel in negative temperatures is also good at over 47 J at -60 °C, so it meets the 6th class of impact toughness. Welding structures, after classic gas metal arc welding (GMAW) processes, meet only the second impact toughness class. An improved GMAW process was used by micro-jet cooling application to raise the mechanical properties of the joints. The microstructure and main properties of the joints were carefully analyzed. The influence of using the new suggested welding process on the various properties of the welds is presented (UTS - ultimate tensile strength, YS - yield strength, Poisson ratio, elongation, Young’s modulus). Then, the effects of tests for use in crane bumper construction were checked by using a hybrid finite element method (FEM) analysis.

3

Obróbka cieplna w procesie kwalifikowania technologii spawania łukowego stali. Cz. 1

Makówka Arkadiusz

Stal, Metale & Nowe Technologie

|

2023

|

nr 9-10

8--12

PL

Artykuł opisuje jedno ze szczególnych zagadnień związanych z kwalifikowaniem technologii – obróbkę cieplną po spawaniu, w szczególności w aspekcie wymagań dodatkowych opisanych w normach dotyczących różnych zastosowań (normach wyrobów) uznanych specyfikacjach technicznych oraz raporcie technicznym ISO/TR 14745.

4

How to replace the original material for the welded structure manufacturing

Ivković Djordje, Arsić Dušan, Cvetković Radica Prokić, Popović Olivera, Nikolić Ružica R., Bokuvka Otakar

Production Engineering Archives

|

2023

|

Vol. 29, Iss. 4

369-378

EN

Due to difficult pandemic situation with COVID-19 decease, as well as due to current geopolitical circumstances in the world, we are facing the shortage of steel and therefore the impossibility of delivering the contracted products within the agreed deadlines. It is thus necessary to find suitable steel for replacement. The procedure for selecting one such steel for substituting the deficit steel 25CrMo4,for the purposes of producing a responsible welded assembly, is described in this paper. After the careful analysis, the steel 42CrMo4 was taken into consideration as a possible substitute material. Prior to applying the new selected steel, it was necessary to perform the following tests: analyze its chemical composition, determine its most important mechanical properties and evaluate its weld ability. Then, the optimal welding and heat treatment technologies were determined, so that the quality of the responsible welded structure would meet all the requirements, as the structure made of originally used steel. For the new steel, all the mentioned and some additional tests were conducted and the appropriate welding technology was prescribed. To verify the selected technology, appropriate tests were conducted on the model welded samples, the results of which are presented in this paper. Based on the analysis of the obtained results, it was concluded that the 25CrMo4 steel can be replaced by the 42CrMo4 steel, however, with the mandatory application of appropriate supplementary measures.

5

Metody upraszczania procesów produkcyjnych w aspekcie braków kadrowych

Lonkwic Paweł

Obróbka Metalu

|

2023

|

nr 3

16--20

PL

Rozwój przemysłu maszynowego ukierunkowany jest obecnie na wdrażanie rozwiązań pozwalających na produkcję w jak największym stopniu bez omyłkową. Głównym powodem takiego podejścia są coraz większe braki kadrowe. Odpowiedzią na takie działania jest m.in.: zastosowanie przyrządów uwzględniających Poka-Yoke, których konstrukcja wymusza prawidłowe operacje w procesie produkcyjnym, wdrażanie częściowej automatyzacji lub robotyzacji procesów produkcyjnych. W niniejszym artykule opisano niektóre wdrożenia z zakresu procesów spawalniczych na przykładzie ustawiaka spawalniczego oraz szablonu.

EN

The current development of the machinery industry is aimed at implementing solutions that allow production to the greatest extent possible without errors. The main reason for this approach is growing staff shortages. The answer to such actions are, among others: the use of Poka-Yoke devices, whose design forces correct operations in the production process, the implementation of partial automation or robotization of production processes. In this paper there are described some implementations in the field of welding processes, such as a welding adjuster, an instrument and a template.

6

Influence of the base metal grain size and heat input on decarburization in single pass SAW and multi pass SMAW welded joints of dissimilar ferritic steels

Nimko M. O., Skulskyi V. Yu.

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 119, nr 1

14--26

EN

Purpose This paper aims to assess a separate influence of heat input and base metal grain size on microstructural evolution in the weld adjacent zone of bainitic steels with 1.5…2.0% Cr, welded or overlayed with consumables with 9% Cr after post-weld heat treatment. Design/methodology/approach Analysis of the width of decarburised layer on microphotographs of welded or overlayed specimens after tempering at 750°C. Specimens were made by using different welding approaches: single-pass welding, multi-pass welding and overlaying. Findings It is shown that with an increase of the heat input energy, the width of the resulting decarbonised layer decreases linearly; the increase of the base metal grain size leads to a decrease in the layer width after tempering at 750°C. The microhardness testing showed the average hardness in the decarburised layer of 15Kh2M2FBS steel was 161 HV0.1 (minimum – 154 HV0.1), while the average hardness in the rest of the heat-affected zone was 192 HV0.1. Research limitations/implications Future research may include comparing the creep rupture strength of the weldments made with different welding parameters or base metal grain size to assess the influence of these factors on creep rupture strength. Practical implications Results permit to achieve minimisation of the rate of carbon diffusion in the weld-adjacent area of the heat-affected zone by means of variation of welded parameters and base metal grain size. Originality/value An influence of high-diffusivity paths (grain boundaries) on carbon diffusion in the heat-affected zone of dissimilar weldments was confirmed experimentally; the correlation between base metal grain size/welding parameters and the rate of the diffusion during high-temperature exposure was found.

7

Application of the heat treatment in the welding process of ferritic stainless steels – causes and effects

Walczyk G., Pakieła W., Roszak M., Snopek P.

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 119, nr 2

72--79

EN

Purpose This paper aims to analyse the application, importance and impact of heat treatment operations used in ferritic stainless steel welding processes on the properties of the welds obtained. In addition, the article aimed to formulate the main problems that occur during the welding process of ferritic stainless steels, including, in particular, the phenomenon of ferrite grain growth due to thermal processes. Design/methodology/approach The analysis of the available literature covered issues related to heat treatment processes used in the welding of ferritic stainless steels, taking into account the issue of the growth of the ferrite grain under the influence of heat supplied during welding and the possibility of heat treatment of the obtained welds. The analysis also included determining the possibility of inhibiting the growth of ferrite grains by using elements such as titanium, niobium, and molybdenum, thus improving the strength properties of welds. Findings Organisation of knowledge in the field of the impact on the mechanical properties of ferritic stainless-steel welds and heat treatment processes used before, during, and after welding. Practical implications Properly selected parameters of the welding process of ferritic stainless steels, especially the amount of heat input, together with appropriate heat treatment parameters, should improve the mechanical properties of ferritic stainless steels. Originality/value The analysis of the possibility of a wider application of ferritic stainless steels allowed to draw one of the main conclusions stating that the limited possibilities of using ferritic stainless steels in heavy industry are related to their high susceptibility to ferrite grain growth under the influence of high temperature during welding and, consequently, decreases in strength properties of welding joints made of ferritic stainless steels. Additional heat treatment operations are introduced before, during, or after the sapping process to improve their mechanical properties.

8

Analysis of the process of qualifying the welding technology of S355JR structural steel using the submerged arc welding method

Wieczorska A., Labuda W.

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 118, nr 1

18--27

EN

Purpose This paper presents the issue of welding technology qualification using the example of structural steel S355JR with a plate thickness of 25 mm and 100 mm, bevelling ½V. The main objective of this work was to attempt to perform a full qualification of the submerged arc welding process in accordance with the requirements of PN EN ISO 15614. Particular attention was paid to the issue of the qualification of welding technology. The samples were subjected to non-destructive testing, i.e. visual and penetrant testing, as well as ultrasonic testing and heat treatment. This was followed by destructive testing, including macroscopic testing and hardness testing. According to the proposed procedure for the recognition of submerged arc welding technology, once the necessary tests had been carried out and the protocols with positive results had been obtained. The documentation had been completed, the analysis needed to obtain certificates of conformity for factory production control and welding quality was carried out. Design/methodology/approach Submerged arc welding is often used for highly responsible butt joints, particularly when joining thick components. This has been achieved through the proper design of the preparation of the parts to be welded and the development of a welding technology that practically eliminates the pre-phase that occurs in traditional technology, thereby eliminating the risk of it affecting the quality of the welded joint. Findings During the implementation of submerged arc welding, a number of technological problems were encountered. The first test joints contained many defects, i.e. sticking and slag inclusions inside the welds. In addition, obtaining welds with the correct profile and removing the slag from the weld groove was difficult. These obstacles were eliminated experimentally by carrying out successive tests using different parameters and welding groove geometries. Practical implications The correct implementation of any welding process depends on its input parameters. These parameters include welding current, welding speed, welding current, wire diameter, welding voltage and many others. Submerged arc welding (SAW) is widely used in the industry for manufacturing as it is more reliable, provides deep penetration in the work, ensures a smooth finish on objects, and results in high productivity. Originality/value The technology was developed for a company that manufactures control discs for steam turbines.

9

Mechanical and corrosion properties of Friction Stir Welded and Tungsten Inert Gas welded phosphor bronze

Gopi S., Mohan Dhanesh G., Natarajan Elango

Advances in Materials Science

|

2023

|

Vol. 23, nr 4(78)

83--98

EN

This study investigated the mechanical and corrosion properties of Friction Stir Welded (FSW) and Tungsten Inert Gas (TIG) welded phosphor bronze (CuSn4) joints. Corrosion tests were conducted on the welded joints, and the percentage of weight loss due to corrosion was measured at different time intervals. Results revealed that the percentage of weight loss due to corrosion of the TIG joint increased with time, whereas the percentage of weight loss due to corrosion of the FSW welded joint remained constant. This could be attributed to recrystallisation that happened in the solid-state welding, which reduced corrosion in the FSW welded joint. In addition, tensile tests were conducted to evaluate the strength of the joints. FSW with a spindle speed of 1300 rpm, weld speed of 0.06mm/sec, plunge depth of 0.25mm, pin profile of pentagon, and flat shoulder profile was found to produce good results. TIG welding with a welding speed of 1.75mm/sec, a gas flow rate of 7.5 cm3/min and an amperage of 120A also produced good results. The tensile strength of FSW was found to be approximately 1.6 times higher than that of TIG welding.

10

Modern materials and innovative welding technology used in the construction of antenna mounts

Szczucka-Lasota Bożena, Węgrzyn Tomasz

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2022

|

z. 115

175--182

EN

Telecommunication, transport and civil engineering play an important role in new research areas. New antennas based on innovative materials are being developed. At the same time, the methods of antenna mounting with the use of high-strength materials to ensure high structural rigidity with the lowest possible weight are being planned. These materials include AHSS steels with ultimate tensile strength (UTS) up to 1700 MPa and elevated yield point (YS); however, welded joints made of these steels have much worse mechanical properties, compared to the native materials. In this paper, it was planned to test the MAG welding of DOCOL 1400M steel (AHSS group). Directly after welding, a micro-jet joint cooling was applied. It was determined to create thin-walled joints that could be used in the formation of antenna mounts.

11

Welding of 690 QL steel for the construction of vehicles and antenna elements

Węgrzyn Tomasz, Szczucka-Lasota Bożena, Döring Adam

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2022

|

z. 160

631--638

EN

Purpose: The novelty and the aim of the article is to check the possibility of welding high 9 strength steels with a mixture containing 7000 ppm of nitrogen. Design/methodology/approach: A new welding material and method have been developed in order to obtain a high-quality joint for automotive industry and for antenna holders and towers. The properties of the joint were checked by NDT (Non Destructive test) tests and the strength and fatigue were tested. Findings: Relations between process parameters and the quality of welds. Research limitations/implications: In the future, it can be suggested to investigate the effect of micro addition of nitrogen in gaseous shielding mixtures of the MIG/MAG welding process. Practical implications: The proposed innovation will not cause problems in the production process. Only the innovate shielding gas with micro additives will be modified without affecting the technological process, management and economic aspects. Social implications: Modifying the welding method will not affect the environment and production management methods. Originality/value: It is to propose a new solution with its scientific justification. The article is addressed to manufacturers of high-strength steel for automotive industry and to manufacturers of antenna components and instrumentation.

12

Konduktancja połączeń spawanych torów prądowych szynoprzewodów aluminiowych

Cybulko Piotr, Węgrzyn Tomasz, Szczucka-Lasota Bożena, Krzysztoforski Michał, Döring Adam

Wiadomości Elektrotechniczne

|

2022

|

R. 90, nr 9

28--30

PL

Systemy dystrybucji energii elektrycznej oparte na szynoprzewodach znajdują zastosowanie m.in. w obiektach przemysłowych wykorzystujących instalacje elektryczne o różnych mocach. Wymagania dotyczące zasilania są realizowane przy użyciu różnych grup szynoprzewodów. Rodzaj używanych połączeń toru prądowego w szynoprzewodach wpływa na przewodność elektryczną połączeń i określa warunki, w jakich można korzystać z szynoprzewodów. W tym artykule przedstawiono wpływ typu procesu spawania złączy w szynoprzewodach aluminiowych pod kątem ich przewodności elektrycznej.

EN

Electricity distribution systems based on busducts are used, among others, in industrial facilities using electrical installations with different capacities. The power requirements are realised by using different groups of busducts. The type of current path connections used in busducts influences the electrical conductivity of the connections and determines the conditions under which busduckts can be used. In this paper, the influence of the type of welding process for joints in aluminium busducts on their electrical conductivity is analysed.

13

Improvement of the mechanical properties of mobile platform stainless construction elements

Szczucka-Lasota Bożena, Węgrzyn Tomasz

Transport Problems

|

2022

|

T. 17, z. 4

91--102

EN

Stainless steel could be treated as the main material used to construct various means of transport, including mobile platforms and tank trucks. An austenitic steel known as 316L steel (1.4401) has high resistance to atmospheric corrosion, natural waters, water vapor, alkaline solutions, and acids, even at elevated temperatures. This steel is weldable, although it is also prone to various types of welding cracks. Many factors influence the quality and mechanical properties of a joint. The most significant of these is the appropriate selection of welding parameters, which should be determined precisely and separately for each type of sheet, depending on its thickness and geometric features. The aim of the present article is to study the influence of main TIG (Tungsten inert gas) welding parameters on the creation of proper joints used in the construction of mobile truck platforms or tank trucks. The proper selection of parameters enables the production of welds with good functional properties. A novelty of this article is the proposal to weld each layer of a thick joint with different parameters, which has an important influence on the mechanical properties of the joint. It is expected that the new material and technological solution will yield a joint with good corrosion resistance and increased mechanical properties. This is important in the responsible construction of means of transport, using the example of mobile platforms and tank trucks. Different tests verifying the properties of joints, including non-destructive testing, tensile strength tests, and fatigue tests, as well as a hardness probe, were applied.

14

Spawalnicze metody łączenia stopów tytanu. Cz. II

Szulc Tomasz

Stal, Metale & Nowe Technologie

|

2022

|

nr 1-2

60--66

PL

Tytan, a dokładniej jego stopy, okazał się doskonałym potencjalnym zamiennikiem stali. Ich łączenie jest możliwe z zastosowaniem wielu znanych technologii spawalniczych, ale w każdym przypadku wymaga szczególnego przygotowania procesu. W cz. I omówiono pokrótce podstawowe grupy stopów tytanu pod kątem specyfiki ich łączenia. Cz. II skupia się na metodach łączenia stopów tytanu, poczynając od najbardziej rozpowszechnionych, takich jak GTA, GMA, wiązką elektronów, a na rzadko stosowanych, takich jak lutozgrzewanie, łączenie wybuchowe i dyfuzyjne kończąc.

EN

Joining of titanium and its alloys is possible with the use of a wide range of welding technologies but in any separate case it needs special care and preparation of the process. The main groups of titanium alloys are briefly described regarding their specific joining requirements. Methods of Ti welding are presented, ranging from most widespread, like GTA, GMA and EBW, to the most unusual, like spot-brazing, detonation and diffusion joining. Guidelines and recommendations concerning the specific requirements of titanium welding with the chosen methods are also included.

15

Gazy osłonowe do spawania tytanu, cyrkonu i ich stopów

Niagaj Jerzy

Stal, Metale & Nowe Technologie

|

2022

|

nr 9-10

44---49

PL

W artykule omówiono rodzaj i skład gazów używanych podczas spawania tytanu, cyrkonu i ich stopów, jak również opisano wpływ poszczególnych gazów na proces spawania i jakość złączy spawanych.

EN

The type and composition of gases used in the welding of titanium, zirconium and their alloys are discussed in the paper. The influence of shielding gases on the welding process and quality of welded joints is also described.

16

Improving the quality of products created by additive technologies based on argon-arc welding

Salenko Alexander, Chencheva Olha, Schetynin Viktor, Zagirnyak Mykhaylo, Kostenko Anton, Tsurkan Daniil

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 2

182--186

EN

The article considers the features of additive prototyping with the use of additive material by means of high-energy heating. Mathematical modeling of the process of surfacing of filler metal is performed. A significant influence of the feed and electrical characteristics of the arc on the parameters of the surfacing roller was revealed. Regression equations of influence of parameters of mechanized argon-arc welding on the shape of the seam and parameters of accuracy of the obtained product are determined.

PL

W artykule omówiono cechy prototypowania przyrostowego z wykorzystaniem przyrostu materiału za pomocą nagrzewania wysokoenergetycznego. Przeprowadzane jest matematyczne modelowanie procesu napawania spoiwa. Wykazano istotny wpływ parametrów posuwowych i elektrycznych łuku na parametry walca napawającego. Wyznaczono równania regresji wpływu parametrów zmechanizowanego spawania argonem na kształt spoiny oraz parametry dokładności otrzymanego produktu.

17

Stosowanie termicznej metody prostowania wałów kosiarek bijakowych w przedsiębiorstwie SaMASZ Białystok

Jaroszewicz Jerzy, Szymonik Andrzej, Stolarski Jacek

Dozór Techniczny

|

2022

|

z. 5

10--17

PL

W artykule przedstawiono charakterystykę wału bijakowego, zjawisko powstawania naprężenia spawalniczego, ulepszenie metody prostowania. W uzgodnieniu z przedsiębiorstwem SaMASZ wypracowano propozycje bezpośrednich ulepszeń aktualnego stanowiska roboczego do prostowania. Sformułowano radykalne usprawnienie metody prostowania przez wstępne podgrzania rury przed i podczas procesu spawania, co powinno znacznie zmniejszyć naprężenia spawania. Pomimo zastosowania robotów przemysłowych do spawania uchwytów nadal występuje zjawisko termicznego wykrzywiania wałów bijakowych. Wykrzywienie wg wstępnych obserwacji dotyczy zarówno osi symetrii, jak i powierzchni bocznej rury.

18

Environmental assessment of the arc and the laser welding of austenitic steels

Wyciślik-Sośnierz Joanna, Matusiak Jolanta

Biuletyn Instytutu Spawalnictwa w Gliwicach

|

2022

|

Vol. 66, No. 4

61--75

EN

The article presents results of research work enabling the environmental assessment of the arc and the laser welding of corrosion resistant austenitic steel X5CrNi18-10 (1.4301). The steel, characterised by high corrosion resistance, favourable mechanical properties and good weldability enjoys growing popularity in many industrial sectors. The application of welding technologies in industry necessitates the performance of tests aimed to identify conditions guaranteeing safe work and protecting workers’ health. Welding and allied technologies belong to the group of processes adversely affecting a work environment. Various welding processes trigger the emission of welding fumes and other pollutants containing numerous substances posing health hazards. The performance of environmental assessment makes it possible to identify and analyse how a given product or a technological process affect the environment. The assessment also enables the comparison of manufacturing processes and technologies in order to indicate those characterised by the lowest environmental impact. The primary ingredients of corrosion resistant steels are chromium and/or nickel. The compounds of the aforesaid chemical elements, present in welding fumes, are rated among substances having a potential or proven carcinogenic effect.

PL

W artykule przedstawiono wyniki prac badawczo-rozwojowych, na podstawie których przeprowadzono ocenę ekologiczną procesu spawania łukowego i laserowego stali odpornej na korozję o mikrostrukturze austenitycznej w gatunku X5CrNi18-10 (1.4301). Stal ta, oprócz wysokiej odporności na korozję, charakteryzuje się również dobrymi właściwościami mechanicznymi. Dzięki tym zaletom znajduje zastosowanie w wielu gałęziach przemysłu, a głównymi technikami jej łączenia są technologie spawalnicze. Stosowanie w przemyśle technologii spawalniczych związane jest z potrzebą badania i określenia warunków bezpieczeństwa pracy i ochrony zdrowia pracowników. Spawanie i techniki pokrewne należą do grupy procesów wytwórczych oddziałujących negatywnie na środowisko pracy. Podczas różnych metod spajania do środowiska pracy wydzielane są zanieczyszczenia pyłowe i gazowe, które zawierają liczne substancje niebezpieczne dla zdrowia pracowników. Przeprowadzenie oceny ekologicznej pozwala na identyfikację oraz analizę oddziaływania na środowisko konkretnego produktu lub procesu technologicznego. Analiza środowiskowa umożliwia również porównanie procesów i technologii wytwarzania oraz wskazanie tych, które mają najmniejszy wpływ na środowisko. Jest to szczególnie istotne w przypadku stali odpornych na korozję, których podstawowym składnikiem stopowym jest chrom, a większość z tych stali zawiera również nikiel. Związki tych pierwiastków, występujące w pyle spawalniczym, zaliczane są do substancji o udowodnionym lub prawdopodobnym działaniu rakotwórczym.

19

Finite element simulation of edge welding in a fin plate: a study incorporating experimental measurement of input factors

Sudharsanam V., Sathiya Narayanan C., Shanmugarajan B., Prakash L.

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 4

art. no. e208, 2022

EN

The present paper discusses the finite element analysis (FEA) performed using SYSWELD software, simulating the Gas Metal Arc Welding (GMAW) of a fin plate on one of its edges. The objective of this work is to study how experimentally measured input factors contribute in the close prediction of thermal and mechanical behaviour of the edge welded fin plate, using FE simulation. The fin plate material considered is ASME SA 387 Gr 12 Cl 2 and of size 1200 mm × 50 mm × 6 mm. Three input factors required for the FEA namely the weld profile, solidus temperature, heat input of welding were identified given their possible influence on the accuracy of FEM prediction. All these factors were determined experimentally using appropriate methods. Then, using these factors as inputs, FEA of edge welding in the fin plate was performed in SYSWELD. This was followed by an experimental trial for validation purpose. The trends of thermal history, strain history and longitudinal bending distortion predicted by FEA and their closeness with the experimentally measured values have been discussed. Based on the findings, it was concluded that the experimental measurement of input factors has enabled the accurate FE simulation of edge welding in fin plate.

20

Investigation on the microstructure and mechanical properties of ASTM A131 steel manufactured by different welding methods

Ata Fatih, Calık Adnan, Ucar Nazim

Advances in Materials Science

|

2022

|

Vol. 22, nr 4(74)

32--40

EN

Welding is an indispensable manufacturing process in the shipbuilding industry. The fierce competition involved often necessitates a cost-effective and reliable welding method. In this study, the weldabilities, microstructures and some mechanical properties of ASTM A131 (Grade A) steel joints fabrication by submerged arc welding (SAW), metal active gas (MAG) welding and plasma arc welding (PAW) have been investigated. The microstructures of the welds were examined by optical microscopy. The mechanical properties of the joints were determined by microhardness measurements, tensile and impact tests. The results showed that tensile strength of the joints reached a tensile strength of up to 462 MPa. The locations of the fractures were always adjacent to the base metal. The Charpy impact energy of the weld metal reached a value of 72.5 J, which was 25 % higher than that of the base metal at 57.7 J. A relatively high hardness of 221 HV was obtained in the PAW method compared to 179 HV in the base metal.