Effect of Oxygen Content on Toughness in High Strength Weld Metal

2010 ◽  
Vol 638-642 ◽  
pp. 3687-3692 ◽  
Author(s):  
Shuichi Nakamura ◽  
Toshiei Hasegawa ◽  
Ryuuichi Shimura ◽  
Isamu Kimoto
Keyword(s):  
Oxygen Content ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Harmful Effect ◽  
High Strength ◽  
Fracture Initiation ◽  
Initiation Point ◽  
Weld Metals ◽  
Effect Of Oxygen ◽  
Welding Processes

The effect of oxygen content on toughness in the high strength weld metals with full martensitic microstructures was investigated for Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). Solid and Flux cored two types wires were examined for their influence on the resulting oxygen content in weld metals. It has succeeded in controlling the oxygen contents without changing welding processes. As expected, the increasing oxygen content obviously decreased the upper shelf energy (vEshelf). One of the primary reasons of this tendency is considered that the higher density of oxide makes dimples on the ductile fracture surface smaller. On the other hand, as unexpected, the oxygen content from 7 to 450 ppm had no impact on the fracture appearance transition temperature (FATT), and oxides at the brittle fracture initiation point have not been found. This result supports that the oxides in high strength full martensitic weld metals (Vickers hardness = 360 ~ 430) have no harmful effect on FATT.

Investigation of Microstructure and Hardness Properties of Hardfacing Surface on SCM 440 Alloy Steel by Using Metal Active Gas and Flux Cored Arc Welding Processes

2017 ◽  
Vol 728 ◽  
pp. 31-35 ◽  
Author(s):  
Siva Sitthipong ◽  
Prawit Towatana ◽  
Amnuay Sitticharoenchai
Keyword(s):  
Alloy Steel ◽  
Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Side Plate ◽  
Weld Metals ◽  
Flux Cored Arc Welding ◽  
The Difference ◽  
Arc Welding Process ◽  
Welding Processes

This research aimed to investigate the microstructure and hardness properties of hardfacing surface on SCM440 alloy steel by using metal active gas and flux cored arc welding processes. Due to the difficulty of welding the high strength steel, the changes in base metals’ microstructures were found after welding. Preheating the specimens at 350°C and post weld heat treatment the specimens at 550°C were performed for 1 hour, to reduce the residual stresses and avoid the undesired formation of microstructures. The weld metals’ microstructures that were found from both welding processes are acicular ferrite, polygonal ferrite and side plate ferrite. The hardness value of weld metal resulted from flux cored arc welding process is higher than that of the metal active gas welding process. Each welding process produced different quantities of weld metals’ microstructures, causing the difference in hardness values. The data will be used for investigating and improving parameters of shaft repairing, in order to use it more effectively.

Hybrid Laser-Arc Welding of HSLA-65 Steel Plate: Microstructural and Mechanical Property Evaluation of Butt Welds

2012 ◽  
Vol 706-709 ◽  
pp. 2992-2997 ◽  
Author(s):  
Cameron Munro ◽  
Allison E. Nolting ◽  
Xin Jin Cao ◽  
Priti Wanjara
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Hsla Steel ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
High Heat ◽  
Impact Testing ◽  
Fibre Laser ◽  
Butt Welds ◽  
Welding Processes

High strength low alloy (HSLA) steel, namely HSLA-65, has shown promise as a replacement for more common high strength shipbuilding steels. However, conventional high heat input welding processes can cause significant distortion, often requiring expensive post-weld reworking. Butt welds in HSLA-65 steel were fabricated using a hybrid fibre laser-gas metal arc welding (GMAW) procedure to investigate the efficacy of distortion mitigation via low heat input joining. Heat input from the laser and arc sources were roughly equal at ~5.2 kW each, and plates were welded in either the laser-leading or arc-leading configuration. In either case, butt welds in ~9 mm thick plates could be made in a single pass at a total heat input of ~0.4 kJ/mm. Welding induced distortion was minimal. Analysis of the microstructure and microhardness of the welds is provided, along with some preliminary results of mechanical and impact testing.

Hybrid Laser/Gas Metal Arc Welding of High Strength Steel Gas Transmission Pipelines

2008 ◽  
Author(s):  
Ian D. Harris ◽  
Mark I. Norfolk
Keyword(s):  
Fiber Laser ◽  
High Power ◽  
Arc Welding ◽  
Fiber Lasers ◽  
Band System ◽  
Gas Metal Arc Welding ◽  
High Strength ◽  
Travel Speed ◽  
Metal Arc Welding ◽  
Welding Processes

Despite significant investment, one-shot welding and power beam processes have not been very successful in achieving real benefits in pipeline construction. The most promising of the newer and more innovative welding processes is the hybrid Laser/arc welding process (HLAW), which can complete 5G welds, assure weld soundness, material properties, and an acceptable geometric profile. The combination of new lasers and pulsed gas metal arc welding (GMAW-P) power source technologies have led to important innovations in the HLAW process that have been shown to increase the travel speed for successful root pass welding. In particular, high power Yb fiber lasers with high efficiency (25% compared with 3% for a Nd:YAG laser) allow a 10kW laser to be built the size of a refrigerator. This allows for previously unheard of portability and power levels for use outside the laboratory and on the pipeline right-of-way. The objective was to develop and apply an innovative HLAW system for mechanized welding of high strength, high integrity, pipelines and develop 5G welding procedures for X80 and X100 pipe, including mechanical testing to API 1104. The main goal of a cost-matched JIP was to develop a prototype hybrid high power Yb fiber laser and GMAW head based on a commercially available bug and band system (Figure 1). Under the DOT project, the subject of this paper, innovative technologies for pipeline girth welding were developed. External hybrid root pass welding techniques were developed for variations of laser power (4–10 kW) and root face thickness (4–8 mm) as this has the greatest potential to meet existing pipeline integrity requirements and facilitate the use of new high power Yb fiber lasers for high speed HLAW of pipe root passes. Following the integration of the Yb fiber laser and GMAW head onto a commercially available bug and band system (CRC-Evans P450) the system was used to achieve full penetration welds with a 4 mm root at a travel speed of 2.3 m/min. The root welds were made in a “double down” configuration using laser powers up to 10kW and travel speeds up to 3 m/min. The final objective of the project is to demonstrate the hybrid LBW/GMAW system under field conditions.

scholarly journals PC-GMAW effect on the welding thermal cycle and weld metal geometry for high strength steels

2020 ◽  
Vol 1 ◽  
pp. 5-16
Author(s):  
Anatoliy Zavdoveev ◽  
Valeriy Poznyakov ◽  
Hyuong Seop Kim ◽  
Massimo Rogante ◽  
Mark Heaton ◽  
...  
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Low Frequency ◽  
High Strength Steels ◽  
Welding Current ◽  
High Strength ◽  
High Amplitude ◽  
Depth Of Penetration ◽  
Temper Ature Range ◽  
Welding Processes

Welding of medium carbon alloy steels used in the manufacture of special-purpose machinery imposes to solve two mutually exclusive problems – to increase the depth of penetration of the base metal and to reduce the width of the thermal impact zone of the welded joints. To successfully solve this problem, it is necessary to use arc welding processes with a concentrated heat source. One of these processes is pulsed current gas metal arc welding (PC-GMAW). The present researches have allowed estab-lishing, that with PC-GMAW change of welding current is a difficult character, namely: on high-frequency impulse signal (60 kHz), impulses of the current of low frequency (from 90–150 Hz) are imposed. The change in the values of the mean welding current at PC-GMAW is achieved by increasing the pause current and the frequency of high-amplitude current pulses. It is shown that the PCGMAW allows reducing the amount of metal splashing, to increase the depth of penetration (almost 2 times) in comparison with stationary welding. At the same time, the cooling rate of HAZ metal in the temper-ature range 600–500°C decreases almost 1.5 times, which allowed to reduce the width of HAZ by 40%.

scholarly journals Porosity Characteristics and Effect on Tensile Shear Strength of High-Strength Galvanized Steel Sheets after the Gas Metal Arc Welding Process

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1077 ◽  
Author(s):  
Seungmin Shin ◽  
Sehun Rhee
Keyword(s):  
Shear Strength ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Galvanized Steel ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Tensile Test Specimen ◽  
Metal Arc Welding

In this study, lap joint experiments were conducted using galvanized high-strength steel, SGAFH 590 FB 2.3 mmt, which was applied to automotive chassis components in the gas metal arc welding (GMAW) process. Zinc residues were confirmed using a semi-quantitative energy dispersive X-ray spectroscopy (EDS) analysis of the porosity in the weld. In addition, a tensile shear test was performed to evaluate the weldability. Furthermore, the effect of porosity defects, such as blowholes and pits generated in the weld, on the tensile shear strength was experimentally verified by comparing the porosity at the weld section of the tensile test specimen with that measured through radiographic testing.

Microstructural Effects between AHSS Dissimilar Joints Using MIG and TIG Welding Process

2015 ◽  
Vol 1766 ◽  
pp. 29-35 ◽  
Author(s):  
G.Y. Pérez Medina ◽  
M. Padovani ◽  
M. Merlin ◽  
A.F. Miranda Pérez ◽  
F.A. Reyes Valdés
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Hardness ◽  
Inert Gas ◽  
Mechanical Degradation ◽  
Low Alloy Steels ◽  
Dissimilar Joints ◽  
Lap Shear ◽  
Welding Processes

ABSTRACTGas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.

Effect of DE-GMAW (Double Electroda Gas Metal Arc Welding)’s Resistance on Mechanical and Physical Properties of Aluminium Alloy Weld

2018 ◽  
Vol 789 ◽  
pp. 64-68
Author(s):  
Yustiasih Purwaningrum ◽  
Medilla Kusriyanto ◽  
Rudi Kurniawan ◽  
Okto Akbar Rizky
Keyword(s):  
Physical Properties ◽  
Aluminium Alloy ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Weld Metals ◽  
Metal Arc Welding ◽  
Mechanical And Physical Properties ◽  
Double Electrode ◽  
Gmaw Welding

This paper presented the effect of DE-GMAW (Double electrode gas metal arc welding)resistance on mechanical and physical properties of aluminium alloywelded. DE-GMAWis amethodof welding process that use two electrode. A non consumable torch is added to bypass the current inorder to reduce the heat input. The variation resistance used were 15Ω, 30Ω and 45Ω. Universaltesting machine and Vickers microhardness were used to measured mechanical properties of weldmetals with respect to strength and hardness. The microstructure was investigated by microscopeoptic with 100 x magnification. The grain size of weld metals with resistance value 30Ω is finer than15Ω and 45Ω. Dye penetrant test shows DE-GMAW welding machine that made have goodperformance because it can produce welding joint without surface crack. The results show thatresistance values optimum to DE-GMAW welding on aluminium alloy 5051 with 4 mm thickness is30Ω. It can be seen from the tensile test that shows the highest tensile strength is found in the DEGMAWwelding with resistance values 30Ω.

A study on sustainability assessment of welding processes

2019 ◽  
Vol 234 (3) ◽  
pp. 501-512 ◽  
Author(s):  
Jaber Jamal ◽  
Basil Darras ◽  
Hossam Kishawy
Keyword(s):  
Arc Welding ◽  
Social Impact ◽  
Sustainability Assessment ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Friction Stir ◽  
Gas Tungsten Arc ◽  
Metal Arc Welding ◽  
Sustainability Assessments ◽  
Welding Processes

The concept of “sustainability” has recently risen to take the old concept of going “green” further. This article presents general methodologies for sustainability assessments. These were then adapted to measure and assess the sustainability of welding processes through building a complete framework, to determine the best welding process for a particular application. To apply this methodology, data about the welding processes would be collected and segregated into four categories: environmental impact, economic impact, social impact, and physical performance. The performance of each category would then be aggregated into a single sustainability score. To demonstrate the capability of this methodology, case studies of three different welding processes were performed. Friction stir welding obtained the highest overall sustainability score compared to gas tungsten arc welding and gas metal arc welding.

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