Abstract When a weldment suffers structural impact, the base and filler metals ductility is one of the main features. However, despite the increasing use of high strength low alloy steels (HSLA), this factor is not always considered and it can result in global and/or localized instabilities within a structure. So, the main objective of this work was to compare the behavior to structural impact of welded I-profiles, made with ASTM A36 and EN10149-2 S700MC, a regular and a HSLA structural steel, respectively, using GMAW process and AWS ER70S-6 and AWS ER110S-G as filler metals, which produce weld metals with great differences in tensile strength and ductility. Besides, all weldments were made with both filler metals and the profiles with or without stiffening reinforcements (on the web), keeping the original finishing of the fillet welds. Among the main results, the behavior of the material with high strength (EN10149-2 S700MC) when subjected to dynamic loading, have shown fracture on the upper flange, with crack lengths significantly greater than those presented by ASTM A36 steel, under the same welding and loading conditions. Furthermore, the presence of vertical reinforcement acts as a stiffening of the structure and ends up transferring the load to the opposite flange of the profile, however without nullifying the fracture condition in the high-strength material. features However HSLA, , (HSLA) andor So Iprofiles, Iprofiles I profiles, I-profiles A A3 EN101492 EN EN10149 2 EN10149- S700MC SMC S MC steel respectively ER70S6 ERS ER70S 6 ER ER70S- ER110SG ERSG ER110S G Besides web, web web) welds results (EN10149- conditions Furthermore profile highstrength (HSLA EN1014 SG (EN10149 EN101 (EN1014 EN10 (EN101 EN1 (EN10 (EN1 (EN

Resumo Quando uma estrutura soldada sofre impacto estrutural, a ductilidade do material é uma das características preponderantes. Contudo, com o crescente destaque e utilização dos aços de alta resistência e baixa liga (ARBL) nem sempre este fator é considerado na sua utilização. Isto pode resultar em instabilidades globais e/ou localizadas numa estrutura. Desta forma, o objetivo principal deste trabalho foi comparar o comportamento ao impacto estrutural de perfis I soldados, produzidos com ASTM A36, um aço estrutural “comum”, e EN10149-2 S700MC, aço ARBL, soldados em filete por processo de soldagem por arco elétrico com atmosfera de proteção gasosa MAG (GMAW) e utilizando metais de adição, AWS ER70S- 6 e AWS ER110S-G, que depositam metais de solda com grandes diferenças em resistência à tração e ductilidade. No desenvolvimento deste trabalho foram elaborados conjuntos soldados (CS) na forma de perfis I de chapas soldadas e mantendo-se as soldas com acabamento original. Os CS foram feitos em ambos materiais variando o metal de adição e condições de reforços. Entre os principais resultados, destaca-se o comportamento do material de alta resistência (EN10149-2 S700MC) quando submetido a carregamento dinâmico, apresentou fratura na mesa superior, com comprimentos significativamente maiores que os apresentados pelo aço ASTM A36, sob mesmas condições de soldagem e carregamento. Além disso, a presença de reforço vertical na estrutura acaba por transferir o carregamento para a mesa oposta do perfil, porém sem anular a condição de fratura no material de alta resistência. preponderantes Contudo ARBL (ARBL eou ou A36 A comum, comum , “comum” EN101492 EN EN10149 2 EN10149- S700MC SMC S MC GMAW (GMAW ER70S ERS ER ER110SG, ER110SG ERSG ER110S G, G ER110S-G (CS mantendose mantendo se original reforços resultados destacase destaca (EN10149- dinâmico superior disso perfil A3 “comum EN1014 SG (EN10149 EN101 (EN1014 EN10 (EN101 EN1 (EN10 (EN1 (EN

Abstract The wire arc additive manufacturing process or WAAM (Wire Additive Arc Welding) is recognized as a process able of making pieces of high geometric complexity, with mechanical properties comparable to those of the cast material. However, there are significant challenges associated with WAAM, such as undesirable microstructures and mechanical properties, high residual stresses and geometric distortion. This study aims to contribute to the selection of deposition parameters for VP50IM steel using WAAM via pulsed TIG (Tungsten Inert Gas) and characterization of the generated stacking, using the Central Composite Complete methodology, CCC. In this study, the peak (Cp) and base (Cb) current, wire feed speed during peak (Vap), base (Vab) and welding speed (Vs) were varied. The ideal parameter presented was Cp=200A, Cb=100A, Vap=2.9cm/min, Vab=1.2cm/min and Vs=20cm/min. Tensile tests showed up to 15% greater resistance in the samples in the longitudinal section in the welding direction compared to the transverse direction. Hardness tests demonstrated up to 9% less hardness at the center of the stack compared to the top and bottom. The fracture analysis of the specimens showed ductile fracture. Wire Welding complexity material However distortion VPIM VP IM Tungsten Gas stacking methodology CCC Cp (Cp Cb (Cb current Vap, Vap , (Vap) Vab (Vab Vs (Vs varied Cp200A CpA 200A A Cp=200A Cb100A CbA 100A Cb=100A Vap29cmmin Vapcmmin 2 9cm min cm Vap=2.9cm/min Vab12cmmin Vabcmmin 1 2cm Vs20cmmin Vscmmin 20cm Vs=20cm/min 15 9 bottom (Vap cmmin

Resumo O processo de manufatura aditiva a arco arame ou WAAM (Wire Additive Arc Welding) é reconhecido como um processo capaz de confeccionar peças de elevada complexidade geométrica, com propriedades mecânicas comparáveis às do material fundido. Entretanto, existem desafios significativos associados ao WAAM, como microestruturas e propriedades mecânicas indesejáveis, elevadas tensões residuais e distorção geométrica. Este estudo visa contribuir com a seleção de parâmetros de deposição do aço VP50IM utilizando WAAM via TIG (Tungsten Inert Gas) pulsado e caracterização do empilhamento gerado, utilizando a metodologia Central Composto Completo, CCC. Neste estudo variou-se a corrente de pico (Cp) e de base (Cb), velocidade de alimentação de arame durante pico (Vap), base (Vab) e velocidade de soldagem (Vs). O parâmetro ideal apresentado foi Cp=200A, Cb=100A, Vap=2,9cm/min, Vab=1,2cm/min e Vs=20cm/min. Ensaios de tração mostraram uma resistência até 15% maior nas amostras na seção longitudinal ao sentido de soldagem em comparação ao sentido transversal. Ensaios de dureza demonstraram uma dureza até 9% menor no centro do empilhamento em comparação ao topo e base. A análise de fratura dos corpos de prova evidenciou fratura dúctil. Wire Welding geométrica fundido Entretanto indesejáveis VPIM VP IM Tungsten Gas gerado Completo CCC variouse variou se Cp (Cp Cb, Cb , (Cb) Vap, Vap (Vap) Vab (Vab Vs. Vs . (Vs) Cp200A CpA 200A Cp=200A Cb100A CbA 100A Cb=100A Vap29cmmin Vapcmmin 2 9cm min cm Vap=2,9cm/min Vab12cmmin Vabcmmin 1 2cm Vs20cmmin Vscmmin 20cm Vs=20cm/min 15 transversal 9 dúctil (Cb (Vap (Vs cmmin

Abstract Underwater wet welding using the flux-cored self-shielded wire (FCAW-S) process has been the focus of study in recent years mainly due to its higher productivity compared to the shielded metal arc welding (SMAW) process. In the present investigation, the effect of an increase in heat input on the geometric and microstructural characteristics of weld beads on the ASTM A36 steel plate is evaluated. For this purpose, three experimental weld beads have been produced at different travel speeds, resulting in three different levels of heat input. The geometric characteristics evaluated were the penetration, reinforcement, and heat-affected zone (HAZ) width. In addition, the analysis of the internal porosity and the microstructure in the cross-section of each weld bead was realized. The main results showed that the increment in heat input increases the HAZ's reinforcement, penetration, and width. On the other hand, the microstructure of the fusion zone consisted of ferrite and bainite, while the presence of martensite was detected in the coarse-grained HAZ. The general analysis of the results indicated that it is possible to obtain class B welds according to underwater welding code AWS D3.6. fluxcored flux cored selfshielded self FCAWS FCAW S (FCAW-S SMAW (SMAW investigation A A3 purpose speeds penetration reinforcement heataffected affected HAZ (HAZ width addition crosssection cross section realized HAZs s hand bainite coarsegrained coarse grained D36 D D3 6 D3.6 D3.

Resumen La soldadura subacuática mojada utilizando el proceso con alambre tubular autoprotegido ha sido foco de estudio en los últimos años debido principalmente a su mayor productividad en comparación con el proceso de soldadura manual con electrodo revestido. En la presente investigación se evalúa el efecto del aumento del aporte térmico sobre las características geométricas y microestructurales de cordones de soldadura desarrollados sobre placas de acero ASTM A36. Para este propósito, fueron realizadas tres soldaduras experimentales con diferentes velocidades de avance resultando en tres niveles diferentes de aportación térmica. Las características geométricas evaluadas fueron la penetración, el refuerzo y el ancho de la zona afectada por el calor (ZAC), además, se llevó a cabo el análisis de la porosidad interna y de la microestructura en la sección transversal de cada cordón. Los principales resultados mostraron que el aumento de aporte térmico incrementa el refuerzo, la penetración y el ancho de la ZAC. Por otra parte, la microestructura de la zona de fusión consistió básicamente de ferrita y bainita, mientras que en la ZAC se detectó presencia de martensita. El análisis general de los resultados indicó que es posible obtener soldaduras clase B según el código de soldadura AWS D3.6. revestido A36 A propósito térmica ZAC, , (ZAC) además cordón parte bainita martensita D36 D D3 6 D3.6 A3 (ZAC D3.

Abstract Accurate measurement of the residual stress in welded joints is still a major challenge for both welding quality control and non-destructive testing. One of the most recent and innovative magnetic techniques for this purpose, known as Magnetic Barkhausen Noise (MBN), is based on the reorganization of magnetic domains (regions with uniform magnetic orientations) in the presence of a varying magnetic field in the studied ferromagnetic material. A significant difficulty in using this method for the analysis of welded joints lies in evaluating of the contribution that each altered material property induces in the resulting noise signal. Therefore, the objective of this study was to correlate the MBN signal with the typical changes that occur in the weld bead and its specific regions during the welding process applied to ASTM A36 steel. Thus, the root mean square (RMS) value of the signal was correlated with micro- and macrostructural changes in the joint, as well as with hardness and residual stress state, including its tensile and compressive magnitudes, demonstrating to be an effective non-destructive tool for characterizing of welded structures. nondestructive non destructive testing purpose MBN, , (MBN) orientations Therefore A3 steel Thus RMS (RMS micro joint state magnitudes structures (MBN

Abstract In this present examination, AA6092 alloys are friction-stir welded at various welding conditions to develop a welded joint with optimal ultimate tensile strength (UTS) and microhardness. This work deals with replacement of application of AA6061 alloys as bumper and bonnet by means of AA6092 alloys and this alloys tensile strength and microhardness is further increased by performing friction stir welding. This study investigates the performance of the friction stir welded butt joints of AA6092 alloys by varying the FSW process parameters such as tool rotational speed (TRS), welding speed (WS), axial load (AL), tool tilt angle (TTA), tool pin profile (TPP), shoulder diameter (SD), etc. In the current investigation, the empirical relationships are developed between most contributing FSW process parameters (TRS, WS, and AL) and their output responses (UTS and weld nugget microhardness (WNH)). The optimal UTS and WNH is predicted by the desirability approach of response surface methodology (RSM). The conforming values of input FSW process parameters are TRS of 1451.67 rpm, WS of 42.22 mm/min, and AL of 5.29 kN. For the existing examination, calculated UTS and WNH are 465.6 MPa and 151.8 HRB respectively, and the results of validation experiments are also invariable with these values. examination AA AA609 frictionstir AA606 TRS, , (TRS) (WS) AL, (AL) TTA, TTA (TTA) TPP, TPP (TPP) SD, SD (SD) etc investigation (TRS WNH. . (WNH)) RSM. RSM (RSM) 145167 1451 67 1451.6 rpm 4222 42 22 42.2 mmmin mm min mm/min 529 5 29 5.2 kN 4656 465 6 465. 1518 151 8 151. respectively AA60 (WS (AL (TTA (TPP (SD (WNH) (RSM 14516 145 1451. 422 4 2 42. 52 5. 46 15 AA6 (WNH 14 1

Abstract Stainless steels enjoy a favorable scenario for applications in various fields of engineering. The proper choice of welding parameters for these metals can result in greater productivity through increased equipment life. Thus, the objective of this work is to evaluate the influence of heat input on the microstructure present in the heat-affected zone (HAZ) of welded steel joints, through metallographic characterization and mechanical tests. The analyzed material is stainless steel plates, welded by the GMAW process, varying the thermal inputs. After this step, the plates were cut, prepared, metallographic analyses, mechanical tensile and bending tests performed. The quantification of phases presents in the heat-affected zone, of the three conditions experienced, 4.2 kJ/cm, 6.7 kJ/cm 9.1 kJ/cm and base metal, were carried out in this study, as well as the mechanical properties of the welded joints. It was verified that the cooling rates were not enough to cause significant microstructural changes in the balance of delta ferrite and martensite phases, found in the HAZ. As for the mechanical properties, they were stable in the tensile and bending tests, with no results that could prevent the application of the material because it was outside the resistance limit required by the application standards. engineering life Thus heataffected affected HAZ (HAZ joints process inputs step cut prepared analyses performed experienced 42 4 2 4. kJcm kJ cm 67 6 7 6. 91 9 1 9. metal study standards

Resumo Os aços inoxidáveis desfrutam de um cenário propicio para aplicações em variados campos da engenharia. A escolha adequada dos parâmetros de soldagem destes metais pode resultar numa maior produtividade através do aumento da vida útil dos equipamentos. Assim, o objetivo deste trabalho é avaliar a influência do aporte térmico na microestrutura presente na zona afetada pelo calor (ZAC) das juntas soldadas do aço, através de caracterização metalográfica e ensaios mecânicos. O material analisado são chapas de aço inoxidáveis, soldadas pelo processo GMAW, variando os aportes térmicos. Após essa etapa, as chapas foram cortadas, preparadas, realizadas análises metalográficas, ensaios mecânicos de tração e dobramento. A quantificação de fases presentes na zona afetada pelo calor, das três condições experimentadas, 4,2 kJ/cm, 6,7 kJ/cm 9,1 kJ/cm e metal base, foram realizadas nesse estudo, como também as propriedades mecânicas das juntas soldadas. Verificado que as taxas de resfriamento não foram suficientes para provocar mudanças microestruturais significativas no balanço das fases ferrita e martensita, encontradas na ZAC. Já às propriedades mecânicas prevaleceram estáveis nos ensaios de tração e dobramento, não havendo resultados que poderiam vir a impedir a aplicação do material por estar fora do limite de resistência exigido pelas normas de aplicação. engenharia equipamentos Assim ZAC (ZAC GMAW térmicos etapa cortadas preparadas metalográficas dobramento experimentadas 42 4 2 4, kJcm kJ cm 67 6 7 6, 91 9 1 9, base estudo martensita

Abstract This article describes the effect of CO2 LBW performance parameters for the welded joint of 1.5 mm thin sheet of Nimonic 80A superalloy. Superalloy 80A used in high temperature application as aero-engine components- blade, rings, exhaust gas turbine part, nuclear tube support and automobile valve. The study focused on optimizing the welding process for the welded joints. Here, LP, WS, FD, and shielding GR will be optimised to improve the weld quality of Nimnic 80A material. Two different optimization techniques were used. The first method is SOO, which is based on the S/N ratio. The aim of this method is to find the Single-optimal values of process parameters. The second method employed MOO, combining the Taguchi grey relational analysis (TGRA) with the principal component analysis (PCA) technique. The researchers used these methods in an effort to identify the set of parameters for obtaining improved weld quality. Authors find best setting parameters p3-v3-f3-g1, with the specific parameter values are LP 2400 W, WS 1800 mm/min, FD 18 mm, and GR 10 lpm. The optimized parameters have yield significant improvements in the depth of penetration 6.03%, weld bead 8.74%, Vickers hardness 12.5%, and tensile strength 16.48% by using TGRA coupled with PCA. CO 15 1 5 1. A superalloy aeroengine aero engine components blade rings part valve joints Here material SOO SN S N ratio Singleoptimal Single optimal MOO (TGRA PCA (PCA technique p3v3f3g1, p3v3f3g1 pvfg p3 v3 f3 g1, g1 p v f g p3-v3-f3-g1 240 W 180 mmmin min mm/min lpm 603 6 03 6.03% 874 8 74 8.74% 125 12 12.5% 1648 16 48 16.48 p3v3f3g p3-v3-f3-g 24 60 0 6.03 87 7 8.74 12.5 164 4 16.4 2 6.0 8.7 12. 16. 6. 8.

Abstract: This work aims to analyze the influence of low temperature on the toughness of a high-strength steel HARDOX 450® joints welded by the Metal Core Arc Welding (MCAW) process. Impact toughness tests (Charpy V-notch test) were performed on the 10 mm base metal (BM), weld metal (WM), and heat-affected-zone (HAZ) at temperatures of -100 °C, -80 °C, -60 °C, -20 °C, 0 °C, and 25 °C to obtain the ductile-brittle transition curve for each of these regions. Additionally, the tensile test and metallographic characterization were performed in order to complement the evaluation of the welded joint. The results of the impact tests showed higher toughness values of the base metal compared to the other two regions of the weld joint analyzed (WM and HAZ). The low toughness present in the HAZ is related to its microstructure composed of Widmanstätten ferrite and coarse grain. However, temperatures of -100 °C and -80 °C show the absorbed energy values in the three regions remarkably close to each other (between 11 J and 20 J). Abstract highstrength high strength 450 MCAW (MCAW process Charpy Vnotch V notch 1 BM, BM , (BM) WM, WM (WM) heataffectedzone heat affected zone (HAZ 100 -10 C 80 -8 60 -6 -2 2 ductilebrittle ductile brittle Additionally HAZ. . HAZ) grain However between J. J) 45 (BM -1 8 - 6 4

Resumo: O presente trabalho visa analisar a influência da temperatura baixa na tenacidade ao impacto de juntas de aço de alta resistência HARDOX 450® soldadas através do processo Metal Core Arc Welding (MCAW). Para tanto foram realizados ensaios de tenacidade ao impacto (ensaio de Charpy com entalhe em V) no metal base de 10 mm (MB), no metal de solda (MS) e na zona termicamente afetada (ZTA) nas temperaturas de -100 °C, -80 °C, -60 °C, -20 °C, 0 °C e 25 °C com o objetivo de levantar a curva de transição dúctil-frágil para cada uma dessas regiões. Adicionalmente, foi realizado ensaio de tração e caracterização metalográfica a fim de complementar a avaliação da junta soldada. Os resultados dos ensaios de impacto mostraram maiores valores de tenacidade do metal base em relação às outras duas regiões da junta solda analisada (MS e ZTA). A baixa tenacidade apresentada na ZTA está relacionada à sua microestrutura composta por ferrita de Widmanstätten e grão grosseiro. Contudo, as temperaturas de -100 °C e -80 °C apresentam os valores de energia absorvida nas três regiões bem próximos entre si (de 11 J a 20 J). Resumo 450 MCAW. MCAW . (MCAW) V 1 MB, MB , (MB) MS (ZTA 100 -10 C 80 -8 60 -6 -2 2 dúctilfrágil dúctil frágil Adicionalmente soldada ZTA. ZTA) grosseiro Contudo J. J) 45 (MCAW (MB -1 8 - 6 4

Abstract The demand for light weight and small components has increased tremendously over the years. The present work describes the plasma micro welding of SS304 alloy. Plasma arc micro welding is carried out on thin sheet to characterize the effect of welding parameters. The proper ranges of welding current at constant welding speed for two different plasma gas flow rates are evaluated to obtain better quality of weld at butt joint configuration. Distortion is a major problem for welded structures especially for the thinner materials. Hence, the variation of process parameters viz. welding current and plasma gas flow rate are studied on weld-induced distortion. Distortion analysis both longitudinal shrinkage and transverse shrinkage are done for six different welding conditions. It is predicted that both longitudinal shrinkage and transverse shrinkage increases with increase in plasma gas flow rate and current. The tensile strength and microstructure are also determined at different gas flow rates and welding currents. This may be due to the application of more heat at higher values. years SS SS30 alloy configuration materials Hence viz weldinduced induced distortion conditions currents values SS3

Abstract This paper shows results of an investigation on the behavior of assemblies produced with welded fillet joints subjected to eccentric, quasi-static and “out-of-plane” structural impact loads. Therefore, weldments were manufactured, with one of the elements in “balance”, using ASTM A-36 and ASTM A-572 grade 50 structural steels, joined by the process of gas metal arc welding (GMAW or MAG). For the purpose of comparison, all weld beads were made with parameters kept constant and classes AWS ER70S-6 and AWS ER120S-G electrodes. Among the main results, it was observed that in tests with quasi-static loading, for both base metals, the parallel weld beads welded with AWS ER120S-G preheated to 150 °C withstood greater loads for shorter times, and the transverse weld beads withstand smaller loads for longer periods of time. Related to structural impact tests of ASTM A572 grade 50 base metal weldments, the parallel weld beads welded with electrode AWS ER70S-6, preheated to 150 °C, withstood near to 50% of the designed load. Fracture surfaces produced by structural impact loading of the weld beads with the AWS ER120S-G electrode were analyzed by scanning electron microscopy. Parallel weld beads produced fractures witch ductile characteristics, and perpendicular weld beads produced ductile fractures with cleavage planes. eccentric quasistatic quasi static outofplane out plane “out-of-plane Therefore manufactured balance, balance , “balance” A36 A 36 A-3 572 A-57 5 steels GMAW MAG. MAG . MAG) comparison ER70S6 ERS ER70S 6 ER S ER70S- ER120SG ERSG ER120S G electrodes metals 15 C times time A57 ER70S6, 6, load microscopy characteristics planes “balance A3 3 A- 57 A-5 SG 1 A5

Resumo Este artigo mostra resultados de uma investigação sobre o comportamento de conjuntos produzidos com juntas soldadas de filete, submetidos a carregamentos excêntricos, quase estáticos e de impacto estrutural “fora do plano”. Sendo assim, os conjuntos soldados foram fabricados, com um dos elementos em “balanço”, utilizando-se aços estruturais ASTM A-36 e ASTM A-572 grau 50, unidos pelo processo de soldagem a arco com proteção gasosa (MAG). Para fins de comparação, todas as soldagens foram realizadas com os parâmetros mantidos constantes e eletrodos classes AWS ER70S-6 e AWS ER120S-G. Dentre os principais resultados foi observado que nos ensaios com carregamento quase estático, para ambos os metais base, os cordões paralelos soldados com AWS ER120S-G pré-aquecidos a 150 °C suportaram maiores carregamentos por tempos menores, e os cordões transversais suportaram menores carregamentos por tempos maiores. Nos ensaios de impacto estrutural dos conjuntos soldados com metal base ASTM A572 grau 50, cordões paralelos soldados com eletrodo AWS ER70S-6, pré-aquecidos a 150 °C resistiram cerca de 50% da carga projetada. Superfícies de fratura produzidas pelo carregamento por impacto estrutural dos cordões soldados com eletrodo AWS ER120S-G foram analisadas por microscopia eletrônica de varredura. Cordões de solda paralelos produziram fraturas com características dúcteis e cordões perpendiculares fraturas dúcteis com planos de clivagem. filete excêntricos fora plano. plano . plano” assim fabricados balanço, balanço , “balanço” utilizandose utilizando se A36 A 36 A-3 572 A-57 50 MAG. MAG (MAG) comparação ER70S6 ERS ER70S 6 ER S ER70S- ER120SG. ER120SG ERSG ER120S G. G estático préaquecidos pré aquecidos 15 C A57 ER70S6, 6, projetada varredura clivagem “balanço A3 3 A- 57 A-5 5 (MAG SG 1 A5

Abstract The in-service welding of natural gas distribution pipes is a critical operation. The shield metal arc welding (SMAW) process has low cost and is very simple, but it has limitations in the minimum pipe thickness. Gas tungsten inert arc welding (GTAW) employs more qualified operators and expensive welding machines and accessories. However, it can weld thinner pipes. In this work, both processes were tested and compared for the welding of an API 5L grade B pipe, often used in the distribution lines of Rio de Janeiro State. The results obtained showed that both processes gave satisfactory results. The minimum tensile strength was 430 MPa for both methods, under the standard range of 415 to 760 MPa. The impact toughness was 50 and 48 J for GTAW and SMAW, respectively. The GTAW showed more fine grains than the SMAW process. The hardness values in the SMAW HAZ was around 220 HV, while the GTAW HAZ was slightly lower, at 180 HV. For both processes, the hardness measured in the heat affected zone (HAZ) was superior to the base metal (BM), but much lower than the limit of 350 HV considered critical for hydrogen induced cold cracking. inservice service operation (SMAW simple thickness (GTAW accessories However work L State 43 methods 41 76 5 4 respectively 22 18 (HAZ BM, BM , (BM) 35 cracking 7 2 1 (BM 3

Resumo A soldagem em operação de um duto de distribuição de gás natural é uma operação crítica. O processo de soldagem com eletrodo revestido, embora simples e barato, encontra limitações quanto à espessura do duto. O processo TIG exige soldadores mais treinados e equipamentos de maior custo, mas o controle do aporte de calor permite soldar menores espessuras. Neste trabalho, os dois processos foram comparados para a soldagem de um tubo de aço API 5L grau B frequentemente utilizado nas linhas de distribuição. Os resultados mostraram que os dois processos forneceram resultados satisfatórios de propriedades mecânicas, a resistência à tração mínima foi de 430 MPa em ambos os processos, dentro do intervalo esperado de 415 a 760 MPa. A tenacidade também ao impacto foi de 50 e 48 J para as juntas por TIG e eletrodo revestido, respectivamente. Comparativamente, a solda pelo processo TIG apresentou mais regiões de grãos refinados. A dureza da ZTA com eletrodo revestido foi em torno de 220 HV, quanto para o TIG o valor foi ligeiramente menor, 180 HV. Nos dois processos, foi superior ao metal base, porém muito abaixo do valor limite de 350 HV considerado crítico para fissuração por hidrogênio (trinca a frio). crítica barato custo espessuras trabalho L mecânicas 43 41 76 5 4 respectivamente Comparativamente refinados 22 menor 18 base 35 trinca frio. frio . frio) 7 2 1 3

Abstract Numerical simulations are commonly employed for comprehending and prognosticating welding procedures. However, repair often requires supplementary actions such as gouging for defect removal. Thermal cycles and non-uniform expansion and contraction of the base metal can engender internal and residual stresses in the gouged region. Residual stresses can wield influence over mechanical properties, thereby underscoring the necessity for their investigation. This study endeavors to establish a numerical method to simulate gouging while devising a rationale for thermal cutting processes. The model was validated by comparing computational and experimental results, which showed good agreement. Mechanical simulation unveiled residual stresses characterized by modest magnitude. This methodology can prevent mechanical failures in repaired components by providing valuable insights into the effects of the gouging process. procedures However removal nonuniform non uniform region properties investigation processes results agreement magnitude process

Abstract Overlay welding with stainless steels has gained attention in several sectors of industry by increasing the mechanical and electrochemical properties of surfaces, in order to obtain them using lower cost substrates. However, the control of welding parameters can become complex due to the multiple control variables, being of interest to obtain deposits with greater productivity. In this context, the objective of this paper is to analyze the effect of the heat input on weld overlays of austenitic stainless steel 316L-Si obtained by the GMAW process, to determine the best welding conditions. For this, a Design of Experiments was implemented to analyze the response variables, which include heat input, reinforcement, width, dilution and hardness of the weld metal. The models were considered significant, presenting R2>0.9 for all responses, based on a 95% confidence limit. Surface graphs indicated influence of welding speed or/and voltage for all responses, in addition to the results demonstrating optimal parameters for overlays such as high ratio between reinforcement and width (0.631), and low dilution values (8.81%). The microstructural analysis indicated the presence of residual γ-austenite and δ-ferrite in all samples, and also the formation of peninsulas and islands, added to defects such as voids, for some weld deposits. surfaces substrates However variables productivity context 316LSi LSi 316L Si L process conditions metal significant R209 R R2 0 9 R2>0. responses 95 limit orand or 0.631, 0631 0.631 , 631 (0.631) 8.81%. 881 8.81% . 8 81 (8.81%) γaustenite γ austenite δferrite δ ferrite samples islands voids R20 R2>0 063 0.63 63 (0.631 88 8.81 (8.81% R2> 06 0.6 6 (0.63 8.8 (8.81 0. (0.6 8. (8.8 (0. (8. (0 (8 (

Abstract In this study, the influence of heat input on the mechanical properties and microstructure of welded joints in ASTM A572 grade 50 steel using the GMAW process and 90Ar-10CO2 shielding gas was investigated. Process parameters were varied between 20-30 V and 230-250 A, which were adjusted aiming to obtain spray transfer together producing two heat inputs with a 10% difference between them. Visual inspection, tensile tests, microhardness scans, measurements of the width of the heat-affected zone (HAZ), and metallography were performed. The experimental measurements were complemented by calculating the continuous cooling transformation (CCT) diagram of the steel from its chemical composition. The results showed that discontinuity-free and visually acceptable welded joints were obtained. The microstructure of the fusion zone was primarily composed of acicular ferrite, and the HAZ contained a mixture of bainite, pearlite, and ferrite as calculated by the CCT diagram. No statistically significant variations were observed in the microhardness measurements, with the highest value (240 MHV) obtained in the fusion zone. The width of the HAZ varied proportionally with the heat input, while no significant differences were found in the stress results as a function of the heat input. study A A57 5 90Ar10CO2 ArCO 90Ar 10CO2 Ar CO 90Ar-10CO investigated 2030 20 30 20-3 230250 230 250 230-25 10 them inspection tests scans heataffected affected HAZ, , (HAZ) performed (CCT composition discontinuityfree discontinuity free bainite pearlite 240 (24 MHV A5 90Ar10CO 10CO 203 2 3 20- 23025 23 25 230-2 1 (HAZ 24 (2 2302 230- (

Abstract Friction stir welding (FSW) is considered one of the most prominent methods for joining ductile materials. In this process, joining occurs in a plastic state without melting the base metals. Therefore, there is a lack of solidification cracking and shrinking of friction stir weld joints. Although, the improper stirring action of the FSW tool reduces the frictional heat input and flow of plasticized material, which deteriorates the weld joint quality. Insufficient and excessive heat input both results in the formation of weld flaws. The FSW is assisted with various new supporting tools to reduce weld flaws. The main objective of this paper is to provide collective information regarding supportive tool systems employed with FSW for the mitigation or elimination of weld flaws. FSW tool systems such as non-rotational shoulder assisted FSW, counter-rotating twin tool, reverse dual rotation, self-reacting tool, and in-situ rolling tool, and their impact on the weld joint formation is presented in this article. This paper also presented an overview of the remarkable effect of optimizing the FSW process parameters and the influence of tool pin profiles on weld joint quality. From this review, it is concluded that various FSW supporting tool systems significantly reduce the weld flaws. (FSW materials metals Therefore joints Although material quality flaws nonrotational non rotational counterrotating counter rotating rotation selfreacting self reacting insitu situ article review