scholarly journals Effect of Heat Input on Weld Formation and Tensile Properties in Keyhole Mode TIG Welding Process

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1327 ◽  
Author(s):  
Zhenyu Fei ◽  
Zengxi Pan ◽  
Dominic Cuiuri ◽  
Huijun Li ◽  
Bintao Wu ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Heat Input ◽  
Welding Process ◽  
Travel Speed ◽  
Tig Welding ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Weld Formation ◽  
Welding Technology ◽  
Jet Trajectory

Keyhole mode Tungsten Inert Gas (K-TIG) welding is a novel advanced deep penetration welding technology which provides an alternative to high power density welding in terms of achieving keyhole mode welding. In order to facilitate welding procedure optimisation in this newly developed welding technology, the relationship among welding parameters, weld formation and tensile properties during the K-TIG welding was investigated in detail. Results show that except for travel speed, the heat input level also plays an important role in forming undercut defect by changing the plasma jet trajectory inside keyhole channel, leading to the formation of hump in the weld centre and exacerbation of undercut formation. Both undercut defect and root side fusion boundary can act as a stress concentration point, which affects the fracture mode and tensile properties considerably. The research results provide a practical guidance of process parameter optimisation and quality assurance for the K-TIG welding process.

scholarly journals Comprehensive Analysis of TIG Welded Inconel–718 Alloy for Different Heat Input Conditions

2018 ◽  
Vol 7 (3.6) ◽  
pp. 206
Author(s):  
P Jerold Jose ◽  
M Dev Anand
Keyword(s):  
Tensile Properties ◽  
Heat Input ◽  
Inconel 718 ◽  
Welding Process ◽  
Welding Current ◽  
Tig Welding ◽  
Welding Parameters ◽  
Inconel 718 Alloy ◽  
Weld Joints ◽  
Welding Heat Input

In this research, the effects of heat input on tensile properties and microstructure were investigated for super alloy Inconel-718 sheets weld by Tungsten Inert Gas (TIG) welding process. The tensile properties and microstructure of weld joints were evaluated. The experiment was conducted with six different combinations of welding parameters like welding current, voltage and welding speed, which were give in six different welding heat input combinations of welding parameters. The experimental results shows that the welding joints weld with low welding heat input was yield higher tensile properties. From the experimentation it was understand that the tensile properties increases when the welding heat input decrease. Drastic grain coarsening was evidenced when the heat input was increases. For the weld joints experimented in this research it was also observed that amount of laves phase was increased with increase in the welding heat input which is the major fact for noticeable variation in the ultimate tensile strength of the weld joints welded by TIG welding process with different welding heat input. 

Optimization of CA-TIG welding parameters to predict and maximize tensile properties of super alloy 718 sheets for gas turbine applications

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tushar Sonar ◽  
Visvalingam Balasubramanian ◽  
Sudersanan Malarvizhi ◽  
Thiruvenkatam Venkateswaran ◽  
Dhenuvakonda Sivakumar
Keyword(s):  
Tensile Properties ◽  
Gas Turbine ◽  
Inconel 718 ◽  
Electron Beam Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Tig Welding ◽  
Welding Parameters ◽  
Content Type ◽  
Welding Processes

Purpose The primary objective of this investigation is to optimize the constricted arc tungsten inert gas (CA-TIG) welding parameters specifically welding current (WC), arc constriction current (ACC), ACC frequency (ACCF) and CA traverse speed to maximize the tensile properties of thin Inconel 718 sheets (2 mm thick) using a statistical technique of response surface methodology and desirability function for gas turbine engine applications. Design/methodology/approach The four factor – five level central composite design (4 × 5 – CCD) matrix pertaining to the minimum number of experiments was chosen in this investigation for designing the experimental matrix. The techniques of numerical and graphical optimization were used to find the optimal conditions of CA-TIG welding parameters. Findings The thin sheets of Inconel 718 (2 mm thick) can be welded successfully using CA-TIG welding process without any defects. The joints welded using optimized conditions of CA-TIG welding parameters showed maximum of 99.20%, 94.45% and 73.5% of base metal tensile strength, yield strength and elongation. Originality/value The joints made using optimized CA-TIG welding parameters disclosed 99.20% joint efficiency which is comparatively 20%–30% superior than conventional TIG welding process and comparable to costly electron beam welding and laser beam welding processes. The parametric mathematical equations were designed to predict the tensile properties of Inconel 718 joints accurately with a confidence level of 95% and less than 4.5% error. The mathematical relationships were also developed to predict the tensile properties of joints from the grain size (secondary dendritic arm spacing-SDAS) of fusion zone microstructure.

Effects of Wire Rotating Frequency on Metal Transfer Process in Rotating Arc Narrow Gap Horizontal GMAW

2011 ◽  
Vol 189-193 ◽  
pp. 3395-3399 ◽  
Author(s):  
Ning Guo ◽  
Yan Fei Han ◽  
Chuan Bao Jia ◽  
Yong Peng Du
Keyword(s):  
Transfer Process ◽  
High Speed ◽  
Stable Process ◽  
Welding Process ◽  
Metal Transfer ◽  
Welding Parameters ◽  
High Speed Photography ◽  
Narrow Gap ◽  
Weld Formation ◽  
Rotating Arc

The metal transfer process with different welding parameters in rotating arc narrow gap horizontal welding is successfully observed by the high-speed photography system. The effects of wire rotating frequency on metal transfer process in rotating arc narrow gap horizontal welding are novelly explored. The metal transfer with different wire rotating frequency presents different modes. The results indicate that the droplet transfer has stable process with the rotating frequency of 5-20 Hz. And the weld formation is quite shapely. But with the high rotating frequency of 50 Hz, the metal transfer process is not acceptable and the weld formation is very pool. Metal transfer process is one of the most important factors of effecting the weld formation in rotating arc horizontal welding process besides the molten pool behavior and welding thermal circles.

Features of structure formation processes in AA2024 alloy joints formed by the friction stir welding with bobbin tool

2021 ◽  
Vol 23 (2) ◽  
pp. 98-115
Author(s):  
Alexey Ivanov ◽  
◽  
Valery Rubtsov ◽  
Andrey Chumaevskii ◽  
Kseniya Osipovich ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Structure Formation ◽  
Welded Joints ◽  
Heat Input ◽  
Welded Joint ◽  
Welding Process ◽  
Tool Material ◽  
Travel Speed ◽  
Material System ◽  
Friction Stir

Introduction. One of friction stir welding types is the bobbin friction stir welding (BFSW) process, which allows to obtain welded joints in various configurations without using a substrate and axial embedding force, as well as to reduce heat loss and temperature gradient across the welded material thickness. This makes the BFSW process effective for welding aluminum alloys, which properties are determined by their structural-phase state. According to research data, the temperature and strain rate of the welded material have some value intervals in which strong defect-free joints are formed. At the same time, much less attention has been paid to the mechanisms of structure formation in the BFSW process. Therefore, to solve the problem of obtaining defect-free and strong welded joints by BFSW, an extended understanding of the basic mechanisms of structure formation in the welding process is required. The aim of this work is to research the mechanisms of structure formation in welded joint of AA2024 alloy obtained by bobbin tool friction stir welding with variation of the welding speed. Results and discussion. Weld formation conditions during BFSW process are determined by heat input into a welded material, its fragmentation and plastic flow around the welding tool, which depend on the ratio of tool rotation speed and tool travel speed. Mechanisms of joint formation are based on a combination of equally important processes of adhesive interaction in “tool-material” system and extrusion of metal into the region behind the welding tool. Combined with heat dissipation conditions and the configuration of the “tool-material” system, this leads to material extrusion from a welded joint and its decompaction. This results in formation of extended defects. Increasing in tool travel speed reduce the specific heat input, but in case of extended joints welding an amount of heat released in joint increases because of specific heat removal conditions. As a result, the conditions of adhesion interaction and extrusion processes change, which leads either to the growth of existing defects or to the formation of new ones. Taking into account the complexity of mechanisms of structure formation in joint obtained by BFSW, an obtaining of defect-free joints implies a necessary usage of various nondestructive testing methods in combination with an adaptive control of technological parameters directly in course of a welding process.

Effect of the Heat Input in the Transformation of Retained Austenite in Advanced Steels of Transformation Induced Plasticity (TRIP) Welded with Gas Metal Arc Welding

2013 ◽  
Vol 339 ◽  
pp. 700-705 ◽  
Author(s):  
Victor Lopez ◽  
Arturo Reyes ◽  
Patricia Zambrano
Keyword(s):  
Heat Input ◽  
Arc Welding ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Residual Austenite ◽  
Welding Parameters ◽  
Transformation Induced Plasticity ◽  
Metal Arc Welding

The effect of heat input on the transformation of retained austenite steels transformation induced plasticity (TRIP) was investigated in the heat affected zone (HAZ) of the Gas Metal Arc Welding GMAW process. The determination of retained austenite of the HAZ is important in optimizing the welding parameters when welding TRIP steels, because this will greatly influence the mechanical properties of the welding joint due to the transformation of residual austenite into martensite due to work hardening. Coupons were welded with high and low heat input for investigating the austenite transformation of the base metal due to heat applied by the welding process and was evaluated by optical microscopy and the method of X-Ray Diffraction (XRD). Data analyzed shows that the volume fraction of retained austenite in the HAZ increases with the heat input applied by the welding process, being greater as the heat input increase and decrease the cooling rate, this due to variation in the travel speed of the weld path.

scholarly journals Development of Welding P92 Pipes Using the Reduced Pressure Electron Beam Welding Process for a Study of Creep Performance

2014 ◽  
Author(s):  
Nick Bagshaw ◽  
Chris Punshon ◽  
John Rothwell
Keyword(s):  
Electron Beam ◽  
Heat Input ◽  
Power Plants ◽  
Electron Beam Welding ◽  
Welding Process ◽  
Welding Parameters ◽  
Pipe Material ◽  
Reduced Pressure ◽  
Type Iv ◽  
Type Iv Cracking

Boiler and steam piping components in power plants are fabricated using creep strength enhanced ferritic (CSEF) steels, which often operate at temperatures above 550°C. Modification of alloy content within these steels has produced better creep performance and higher operating temperatures, which increases the process efficiency of power plants. The improved materials, however, are susceptible to type IV cracking at the welded regions. A better understanding of type IV cracking in these materials is required and is the basis of the Technology Strategy Board (TSB) UK funded VALID (Verified Approaches to Life Management & Improved Design of High Temperature Steels for Advanced Steam Plants) project. In order to study the relationship between creep performance and heat input during welding, several welds with varying amounts of heat input and resultant HAZ widths were produced using the electron beam welding process. The welding parameters were developed with the aid of weld process modeling using the finite element (FE) method, in which the welding parameters were optimized to produce low, medium and high heat input welds. In this paper, the modeling approach and the development of electron beam welds in ASTM A387 grade P92 pipe material are presented. Creep specimens were extracted from the welded pipes and testing is ongoing. The authors acknowledge the VALID project partners, contributors and funding body: Air Liquide, Metrode, Polysoude, E.ON New Build & Technology Ltd, UKE.ON, Doosan, Centrica Energy, SSE, Tenaris, TU Chemnitz, The University of Nottingham, The Open University and UK TSB. Paper published with permission.

scholarly journals A Study on Vertical Upward Welding of Dissimilar Material and Thickness of Thin Plates Using Novel TIG Welding Process

2019 ◽  
Author(s):  
Ngo Huu Manh ◽  
Nguyen Van Anh ◽  
Murata Akihisa ◽  
Hideno Terasaki
Keyword(s):  
Base Metal ◽  
Heat Input ◽  
Weld Zone ◽  
Welding Process ◽  
Welding Current ◽  
Tig Welding ◽  
Dissimilar Material ◽  
Thin Plates ◽  
Welding Defects ◽  
Welding Position

A study about influence of heat input on welding defects in vertical upward welding position for dissimilar material and thickness using a new variation of TIG welding torch is done with support of advanced inspection methods SEM and EBSD. With vertical upward welding position, control heat input plays an important role to keep the weld stabilization without defects. On the other hand, TIG welding process using a conventional TIG torch (conventional TIG welding process) has low efficiency and it is difficult to control heat input with high accuracy. So, it is considered that using conventional TIG torch is still a challenge for welding thin plates. In this case, a new variation of TIG torch has been developed. This torch used a constricted nozzle to improve plasma arc characteristics. As a result, it can control efficiently the heat input to prevent the excessive or insufficiency for joining thin sheets. For evaluation of welding quality, advanced examination methods SEM and EBSD were applied to directly observe the welding defects. From the results, the formation mechanism of blowhole inside weld zone in case of welding dissimilar material and thickness was discussed. It is pointed out that when sufficient welding current, the change from weld zone to base metal is uniform, no welding defects such as blowhole was seen. However, in case of low welding current, the thinner base metal is insufficient fusion and the change between weld zone and base metal is not uniform. The blowhole was observed at SS400 material side.

Compatibility Welding Parameters with the Results Obtained in Testing of Fracture Mechanics in HSLA Steel

2017 ◽  
pp. 163-193
Author(s):  
Rafael González-Palma ◽  
María Carmen Carnero ◽  
Carlos López-Escobar ◽  
David Almorza ◽  
Pedro Mayorga
Keyword(s):  
Stress Intensity ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Heat Input ◽  
Hsla Steel ◽  
Welding Process ◽  
Welding Parameters ◽  
High Heat Input ◽  
Arc Welding Process ◽  
Experimental Values

Many investigations led to show that no crack begins to propagate to an increase of stress intensity factor. The life of the components of a structure containing premature cracks, can be governed by the degree of subcritical crack propagation. Thus, knowledge of crack propagation to determine the fatigue of the structure is necessary. One problem of steels of high resilience is their low toughness in the HAZ, when they are welded with a high heat input. In this work we have studied nine specimens that have been welded under a submerged arc welding process controlling the welding parameters and checking in the HAZ of such specimens, critical tensions at the ends of the cracks, the critical cracks lengths and stress intensity factors. It is intended to check that the parameters that indicate the values of fracture mechanics in the HAZ, after heat cycle to which the steel has undergone, under a process with a maximum heat input of 2.327kJ /mm, they are still valid, with the welding parameters applied. It is checked a correlation between the theoretical and experimental values.

A Study on the Welding Characteristics of Dissimilar Metal Using a High Power CW Nd:YAG Laser

2007 ◽  
Vol 26-28 ◽  
pp. 539-542
Author(s):  
Ho Jun Shin ◽  
Young Tae Yoo ◽  
Byung Heon Shin
Keyword(s):  
Welding Speed ◽  
Nd:Yag Laser ◽  
Continuous Wave ◽  
Research Work ◽  
Welding Process ◽  
Welding Parameters ◽  
Deep Penetration ◽  
Pressurized Water ◽  
Zone Formation ◽  
Dissimilar Metal

Laser welding process is widely used in the industrial field due to its numerous advantages: a small heat affected zone(HAZ), deep penetration, high welding speed, ease of automation, single-pass thick section capability, enhanced design flexibility, and small distortion after welding. In this paper, the laser weldability of Austenite stainless steel and INCONEL600 at dissimilar metal welds using a continuous wave Nd:YAG laser are experimentally investigated. INCONEL600 is being used in a steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion. Therefore stress corrosion cracking can occur on this material. A research work is conducted to determine effects of welding parameters, on eliminating or reducing the extent welding zone formation at dissimilar metal welds and to optimize those parameters that have the most influence parameters such as focus length, laser power and welding speed were tested.

Analysis of the Influence of the Heat Input and Bead Volume on HAZ Hardness for Submerged Arc Welding Process of Mild Steel Plates

2011 ◽  
Vol 284-286 ◽  
pp. 2469-2472
Author(s):  
Aniruddha Ghosh ◽  
Somnath Chattopadhyaya ◽  
S. Mukherjee
Keyword(s):  
Mild Steel ◽  
Heat Input ◽  
Arc Welding ◽  
Welding Process ◽  
Travel Speed ◽  
Submerged Arc Welding ◽  
Steel Plates ◽  
Critical Set ◽  
Arc Welding Process ◽  
Submerged Arc

In Submerged Arc Welding process involves critical set of variables which are needed to control. An attempt has been made in this paper to find out- the influence of the heat input and bead volume on HAZ Hardness for Submerged Arc Welding Process of Mild steel plates. Mild steel plates are welded by changing input variables (current, voltage, travel speed, i.e. heat input) and Rockwell hardness no. has been observed on welded portion and at the zone adjacent to the welded portion. A detailed analysis of the microstructure changes is carried out to understand the HAZ softening phenomenon.

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