Rail surfacing repairing technique with self-shielded flux-cored wires

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040056
Author(s):  
Jia Chen ◽  
Guoqing Gou ◽  
Zhongyin Zhu ◽  
Wei Gao
Keyword(s):  
Heat Treatment ◽  
Process Parameters ◽  
Great Influence ◽  
Welding Process ◽  
Welding Parameter ◽  
Post Heat Treatment ◽  
Cored Wire ◽  
Preheating Temperature ◽  
Welding Defects ◽  
Cored Wires

A newly self-protecting flux-cored wire was used for simulated U75V rail repairing and five welding process parameters were applied. The influence of welding parameter on the hardness and microstructure of the wire and solder layers was investigated. The single-pass welding process with different preheating parameters and post-treatment parameters were also taken into research. The results showed that the welding process parameters have a significant influence on the weld quality, and mismatched parameters will increase the welding defects. The number of welding layers has a great influence on the hardness and structure. Increasing preheating temperature and a post-heat treatment at a high-temperature can enhance the hardening effect.

scholarly journals A Novel Method of Defect Detection Based on Experimental Investigation of Galvanized Steel Welded Plates Using Wobble Laser Process

2021 ◽  
Author(s):  
Sasan Sattarpanah Karganroudi ◽  
Ahmad Aminzadeh ◽  
Vincent Blériot Feujofack Kemda ◽  
Noureddine Barka
Keyword(s):  
Process Parameters ◽  
Predictive Models ◽  
Welding Process ◽  
Galvanized Steel ◽  
Welding Parameters ◽  
Indentation Hardness ◽  
Hardness Profile ◽  
Weld Width ◽  
Welding Defects ◽  
Geometrical Defects

Abstract This paper aims at investigating the effect of laser welding parameters on the hardness profile, using hardness mapping analyses, and welding geometry of galvanized steel plates. Hardness distribution and geometry deflection of galvanized welded thin plates are commonly applied in fields where the weld quality is of utmost importance. Due to the welding process and material condition, welding galvanized steel is one of the problematic matters in welding technology. Here, the design of experiment (DOE) approach is used to study the effect of process parameters. Using a pattern matrix of micro-indentation hardness experiment, the welding defects are visualized on hardness profile of the weld cross-section. The effect of process parameters on welding defect formation is then qualitatively analyzed. The geometrical defects of welding such as weld width and voids are then quantitatively studied based on analysis of variance (ANOVA), and predictive models of welding voids and weld seam width are developed based on the regression method. Response surface method (RSM) is then applied to define the trend of process factors interaction on the welding defects. The experimental results confirm the reliability of developed predictive models of welding defects geometry, weld width, and voids area of laser-welded galvanized plates.

Study on Welding Techniques of 316L Lined Bimetallic Pipe

2019 ◽  
Vol 944 ◽  
pp. 944-949
Author(s):  
Fa Gen Li ◽  
Xun Ji Li ◽  
Wei Wei Li ◽  
Xian Ming Li ◽  
Ze Liang Chang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Failure Analysis ◽  
Research Work ◽  
Welding Process ◽  
High Hardness ◽  
Gas Production ◽  
Structure Design ◽  
Cored Wire ◽  
Welding Defects ◽  
Weld Corrosion

It is well known that welding technique was often a knotty problem for bimetallic lined steel pipes to use widely. A number of failures in secession of weld cracking and weld corrosion had been observed in oil fields in recent years, which seriously disrupted the order of oil and gas production. To solve welding problems of 316L bimetallic lined pipes, works outcome about failure analysis and welding process research were presented in this paper. Failure analysis results confirmed that Welding defects, high hardness regions was the main reasons about failure problems of weld crack while structure design defects of seal weld and bad back-protection effects of flux-cored wire resulted in weld corrosion. Welding defects in the regions of seal weld became the failure source while the high hardness both in the region of seal weld and weld joint formed the crack propagation channel, and therefore both initially contributed to weld cracking. Additionally owing to the structure design of seal weld, liner layer would be heated over and over again during the period of seal weld and then it was not enough to protect CRA layers from being damaged during the period of girth weld. As a result the corrosion resistance in the welding area was reduced to become a weak area. On the basis of failure analysis, further research work was carried out to improve welding performance. Seal weld structure and girth weld process was improved. The difference of welding wires and welding process was analyzed, and their defects were described separately. Results showed that the welding performance welding by ERNiCrMo-3 and supporting technology was more reliable than ATS-F309L and supporting technology, whether seal weld or butt welding. The distribution and value of the hardness could be effectively controlled; Moreover, corrosion resistance performance was also better. Therefore, the seal weld and girth weld conducted by ERNiCrMo-3 and supporting technology was feasible.

The Comparative Analysis of the Concentration of Microparticles during Mechanized MAG Welding Using Cored Wires

2013 ◽  
Vol 814 ◽  
pp. 76-81
Author(s):  
Dănuţ Mihailescu ◽  
Octavian Frincu ◽  
Marius Corneliu Gheonea
Keyword(s):  
Carbon Dioxide ◽  
Comparative Analysis ◽  
Welding Process ◽  
Mag Welding ◽  
Gas Mixture ◽  
Metal Powders ◽  
Shielding Gas ◽  
Cored Wire ◽  
Metal Frame ◽  
Cored Wires

Use of cored wire - shielding gas (gas mixture) pair, during mechanized MAG welding, causes the microparticles formation which is harmful for the welder’s health. The paper presents the experimental method for determining the concentration of the microparticles generated during MAG welding when rutile cored wires (standard and low fume emission) and metal powder cored wires (standard and low fume emission) are used. Carbon dioxide and the shielding gas mixture are investigated, too. Four types of cored wires were comparatively analysed, when three wire speed values were applied. The research of the microparticles concentration was conducted after each welding bead deposition, at the upper part of the welding enclosure, using MicroDust Pro particulate monitor. After each weld bead was deposited, the metal frame of the welding enclosure was removed, and, the fumes and gases, produced during the welding process, were eliminated through two fans, positioned inside and outside of the equipment. Using rutile cored wire with low fume emission, a decrease of microparticles concentration up to 30% is noticed in comparison with standard rutile cored wire. Using metal powders cored wire with low fume emission, the microparticles concentration is diminished with 12.5% comparing with standard metal powders cored wire.

scholarly journals Managing the influence of microstructure defects on the strength of EN AW 5754 aluminium alloy welded joints executed with the TIG method

2018 ◽  
Vol 182 ◽  
pp. 02025
Author(s):  
Piotr Woźny ◽  
Józef Błachnio
Keyword(s):  
Aluminium Alloy ◽  
Process Parameters ◽  
Welded Joints ◽  
Welding Process ◽  
Inert Gases ◽  
Weld Strength ◽  
Tungsten Electrode ◽  
Welding Defects ◽  
Strong Relation ◽  
The Impact

The paper concerns the issue of the impact of welding defects on the strength of EN AW 5754 aluminium alloy welded joints, executed with the TIG welding method (tungsten inert gas, i.e., a method of welding with a non-consumable tungsten electrode shielded with inert gases). The article presents examples of operating damage to welded joints and discusses the factors impacting the weld quality. The strength test results of welding samples taken under different process parameters were presented. The impact of welding defects and non-conformities identified with a CAT test on the weld joint impact was analysed. The studies showed a strong relation between the presence of welding defects, welding process parameters and weld strength.

Mechanized Welding with Metal Cored Wire

2020 ◽  
Vol 1157 ◽  
pp. 113-122
Author(s):  
Andrey A. Golyakevich ◽  
Leonid N. Orlov ◽  
Sergey Yu. Maksimov
Keyword(s):  
High Performance ◽  
Welding Process ◽  
Global Market ◽  
Cored Wire ◽  
Global Trends ◽  
Wide Range ◽  
Mechanized Welding ◽  
The Stability ◽  
Welding Consumables ◽  
Cored Wires

Currently, there is a steady upward trend in the consumption of flux-cored wires in the global market of welding consumables. One of the rapidly developing technologies for the manufacture of metal structures is shielded gas arc welding with flux-cored wire with a metal core. According to the technology of use, metal cored wires do not differ from solid wires, and even surpass them in some technological characteristics. Taking into account global trends in the development of mechanized welding and the lack of domestic analogues, LLC TM.VELTEK has developed and mastered the manufacturing of high-performance metal cored wire TMB5-MK for welding in mixtures of 82% Ar + 18% CO2, 90% Ar + 10% CO2. The research aimed to study the features of the process of welding with metal cored wire compared to welding with solid wire. It has been established that metal cored wire provides high stability of arc burning in a wide range of welding modes. When welding at the same conditions in the optimal range, the index of stability of arc burning when using solid wire Sv-08G2S is 3 times lower. At the same time, the TMV5-MK wire provides a reduction in spatter losses, an increase in welding productivity and high mechanical properties of the weld metal. It is shown that the stability of the welding process is significantly affected by the electrodynamic properties of the power source and this factor must be taken into account when evaluating the welding and technological properties of welding wires and developing recommendations for their use.

Effect of Pre/Post Heat Treatment on the Friction Stir Welded SSM 356 Aluminum Alloys

2012 ◽  
Vol 488-489 ◽  
pp. 328-334 ◽  
Author(s):  
Worapong Boonchouytan ◽  
Thanate Ratanawilai ◽  
Prapas Muangjunburee
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Welding Speed ◽  
Treatment Condition ◽  
Welding Process ◽  
Heat Treatment Condition ◽  
Post Heat Treatment ◽  
Rotating Speed ◽  
Friction Stir ◽  
Tool Pin

The butt joints of semi solid 356 were produced in as cast conditions by friction stir welding process (FSW). This experiment studied in pre/post heat treatment (T6) using the welding speed 160 mm / min with tilt angle tool at 3 degree and straight cylindrical tool pin. The factors of welding were rotating speed rates at 1320, 1750 rpm and heat treatment conditions. They were divided into (1) As welded (AW) joints, (2) T6 Weld (TW) joints, (3) Weld T6 (WT) joints, (4) T6 Weld T6 (TWT) joints, (5) Solution treated Weld Artificially aged (SWA) joints and (6) Weld Artificially aged (WA) joints. Rotating speed and heat treatment (T6) condition were an important factor to micro, macro structure of metal and mechanical properties of the weld. Increasing rotating speed and different heat treatment condition impacted onto tensile strength due to the defects on joints. Therefore the optimum welding parameter on joint was a rotating speed 1320 rpm, the welding speed 160 mm/min, heat treatment condition of Weld T6 (WT) which obtained the highest tensile strength 228.92 MPa, as well as, highest hardness of 98.1 HV

scholarly journals Effect of Pre-Heating and Post-Heating on Electron Beam Welding of Reduced Activation Ferrite/Martensite Steel

2021 ◽  
Vol 2 (3) ◽  
pp. 225-238
Author(s):  
Yong Zhang ◽  
Jiefeng Wu ◽  
Zhihong Liu ◽  
Songlin Liu ◽  
Mingzhun Lei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Electron Beam ◽  
Electron Beam Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
High Energy ◽  
High Energy Density ◽  
Post Heat Treatment ◽  
Rafm Steel

Reduced activation ferritic/martensitic (RAFM) steels are considered the main candidate material for the water-cooled ceramic breeder (WCCB) in a fusion reactor. High-energy density welding approaches, such as electron beam welding (EBW) and laser beam welding (LBW), are frequently utilized in the welding of RAFM steels. During the welding process, cracks and other defects are prone to appear. In this paper, EBW was selected for the welding of RAFM steels. Those with and without pre-heat and post-heat treatment by electron beams are studied by finite element simulation and trials. The results show that the experimental results are consistent with the simulation. In particular, in the case of similar deformation, the residual stress after electron beam heat treatment is far less than that without heat treatment. Without heat treatment, the residual stress near the weld is more than 400 MPa, while the residual stress after heat treatment is about 350 MPa. As the reduction of residual stress is essential to prevent the occurrence of cracks and other defects after welding, pre-heat and post-heat treatment by the electron beam is deemed as an effective way to greatly improve the welding quality in RAFM steel welding.

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