scholarly journals The influence of manual metal arc multiple repair welding of long operated waterwall on the structure and hardness of the heat affected zone of welded joints

2017 ◽  
Vol 62 (1) ◽  
pp. 327-333 ◽  
Author(s):  
J. Pikuła ◽  
M. Łomozik ◽  
T. Pfeifer
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Power Plants ◽  
Welded Joint ◽  
Weld Bead ◽  
Boiler Steel ◽  
Metallographic Examination ◽  
Metal Arc Welding ◽  
High Degree

Abstract Welded installations failures of power plants, which are often result from a high degree of wear, requires suitable repairs. In the case of cracks formed in the weld bead of waterwall, weld bead is removed and new welded joint is prepared. However, it is associated with consecutive thermal cycles, which affect properties of heat affected zone of welded joint. This study presents the influence of multiple manual metal arc welding associated with repair activities of long operated waterwall of boiler steel on properties of repair welded joints. The work contains the results of macro and microscopic metallographic examination as well as the results of hardness measurements.

scholarly journals Influence of welding method on microstructural creation of welded joints  

2011 ◽  
Vol 57 (Special Issue) ◽  
pp. S50-S56 ◽  
Author(s):  
P. Čičo ◽  
D. Kalincová ◽  
M. Kotus
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Structural Phase ◽  
Welding Parameters ◽  
Welding Method ◽  
Welding Technology ◽  
Metal Arc Welding

This paper is focused on the analysis of the welding technology influence on the microstructure production and quality of the welded joint. Steel of class STN 41 1375 was selected for the experiment, the samples were welded by arc welding including two methods: a manual one by coated electrode and gas metal arc welding method. Macro and microstructural analyses of the experimental welded joints confirmed that the welding parameters affected the welded joint structure in terms of the grain size and character of the structural phase.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

Assessment of Weld Bead Performance for Pulsed Gas Metal Arc Welding (P-GMAW) Using Acoustic Emission (AE) and Machine Vision (MV) Signals Through NDT Methods for SS 304 Material

2020 ◽  
Author(s):  
Rudreshi Addamani ◽  
Holalu Venkatdas Ravindra ◽  
S. K. Gayathri Devi ◽  
Ugrasen Gonchikar
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Cost Effective ◽  
Weld Bead ◽  
Spray Transfer ◽  
Metal Arc Welding ◽  
Ss 304 ◽  
Wire Feed

Abstract To gain high cost effective products along with quality and productivity, Pulsed Gas Metal Arc Welding (P-GMAW) process is used in many highly developed industries for fabrication of welded joints. The input parameters are the most important factors which affects the productivity, quality and cost effective for the welding process. The processes enable low net heat input, stable spray transfer and with low mean current. To enhance efficiencies with constant voltage GMAW process, P-GMAW is an outstanding substitute for those industries which are looking to improve quality of welds since the process helps over varying operator’s skills. It is essential to determine the input/output relationship parameters, in order to recognize and control the P-GMAW welding process. P-GMAW applies waveform control logic to fabricate a very precise control of the arc during speed range and a broad wire feed. The power source switches between low background current and a high peak current between 30 to 400 times per second to obtain modified spray transfer process. The peak current pinches off wire droplets and drive it to the welded joints over this period. The process produces low heat input allowing weld pool to solidify, that metal transfer cannot occur but by the mean time, background current maintains the arc with stable spray transfer. Trials have been conducted on SS 304 material using copper coated filler wire of size 1.4 mm based on the Taguchi’s L27 standard orthogonal array. Current, Gas Flow Rate (GFR) and Wire Feed Rate (WFR) with a constant speed are the input parameters considered to carry out trials. The output parameters are Yield strength (YS, N/mm2), percentage of elongation and Ultimate Tensile Strength (UTS, N/mm2). Indirect response parameters are Viz., AE signals such as welding AERMS, welding AEENERGY, tensile AERMS and tensile AEENERGY along with MV signals like area and height of the weld bead are considered to assess the performance of the weld bead joint. It is clearly observed from the obtained results that an excellent relationship exists between welding AERMS welding AEENERGY with tensile AERMS and tensile AEENERGY along with MV signals which were taken at the time of tensile test to evaluate the performance of the weld bead joint. Verification of the results are carried out through performing different NDT testing methods on weld bead joint Viz., X–radiography, Scanning Electron Microscope (SEM) images to analyse external defects in the welded joints. On different zones of welded joint, Energy dispersive analysis (EDX) examination is carried out for elemental composition.

scholarly journals Impact of Electromagnetic Stirring on the Gas Metal Arc Welding of an MAR-M247 Superalloy

2021 ◽  
Author(s):  
Yu-Chih Tzeng ◽  
Cheng-Yu Lu ◽  
RenYu Chen
Keyword(s):  
Crack Resistance ◽  
Heat Affected Zone ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Weld Bead ◽  
Electromagnetic Stirring ◽  
Metal Arc Welding ◽  
Hole Defects ◽  
The Impact

Abstract In this paper, the impact of electromagnetic stirring (EMS) on the gas metal arc welding (GATW) of an MAR-M247 superalloy was investigated. Results revealed that, without electromagnetic stirring, it was easy for carbides in the heat-affected zone (HAZ) of the weld bead to liquefy during welding, leading to weld bead cracks. Electromagnetic stirring refined the grains in the HAZ and the weld bead, leading to grain strengthening and subsequently resulting in the effective improvement in the hardness of the weld bead. In addition, electromagnetic stirring significantly facilitated the formation of the weld bead by the removal of large inclusions which in turn effectively improved crack resistance at the joint. It also accelerated the floating up of gas holes thereby reducing the generation of gas hole defects.

Optimization of Argon Gas Metal Arc Welding Process Parameters with Regard to Tensile Strength for AISI 310 Stainless Steel Using Taguchi Technique

2022 ◽  
Vol 58 ◽  
pp. 1-10
Author(s):  
Hanmant Virbhadra Shete ◽  
Sanket Dattatraya Gite
Keyword(s):  
Tensile Strength ◽  
Arc Welding ◽  
Welded Joint ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Taguchi Technique ◽  
Argon Gas ◽  
Metal Arc Welding ◽  
310 Stainless Steel ◽  
Arc Welding Process

Gas metal arc welding (GMAW) is the leading process in the development of arc welding process for higher productivity and quality. In this study, the effect of process parameters of argon gas welding on the strength of T type welded joint of AISI 310 stainless steel is analyzed. The Taguchi technique is used to develop the experimental matrix and tensile strength of the welded joint is measured using experimental method and finite element method. Optimization of input parameter is performed for the maximum tensile strength of welded joint using ANOVA. The results showed that welding speed is the most significant factor affecting the tensile strength followed by voltage in argon gas metal arc welding (AGMAW) process. Argon gas welding process performance with regard to the tensile strength is optimized at voltage: 18.5 V, wire feed speed: 63 m/min and welding speed: 0.36 m/min.

Gas metal arc welding of XPF800 steel for automotive industry: Microstructural evaluation and mechanical properties investigation

2021 ◽  
pp. 146442072110567
Author(s):  
Emre Korkmaz ◽  
Cemal Meran
Keyword(s):  
Mechanical Properties ◽  
Base Metal ◽  
Automotive Industry ◽  
Heat Affected Zone ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Charpy Impact ◽  
Optical Microscope ◽  
Metal Arc Welding ◽  
Heat Affected Zone Softening

In this study, the effect of gas metal arc welding on the mechanical and microstructure properties of hot-rolled XPF800 steel newly produced by TATA Steel has been investigated. This steel finds its role in the automotive industry as chassis and seating applications. The microstructure transformation during gas metal arc welding has been analyzed using scanning electron microscope, optical microscope, and energy dispersive X-ray spectrometry. Tensile, Charpy impact, and microhardness tests have been implemented to determine the mechanical properties of welded samples. Acceptable welded joints have been obtained using heat input in the range of 0.28–0.46 kJ/mm. It has been found that the base metal hardness of the welded sample is 320 HV0.1. On account of the heat-affected zone softening, the intercritical heat-affected zone hardness values have diminished ∼20% compared to base metal.

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