Numerical prediction of heat affected zone (HAZ) grain refinement for multiple weld-bead deposits during the SMAW welding process of Cr–Mo–V steel

2003 ◽  
Vol 17 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Z Mazur ◽  
G Urquiza ◽  
C Mariño ◽  
A Hernándex ◽  
G Gonzalez ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Heat Affected Zone ◽  
Welding Process ◽  
Numerical Prediction ◽  
Weld Bead

An integrated evolutionary approach for simultaneous optimization of laser weld bead characteristics

2016 ◽  
Vol 232 (8) ◽  
pp. 1407-1422 ◽  
Author(s):  
C. Govinda Rajulu ◽  
A Gopala Krishna ◽  
Thella Babu Rao
Keyword(s):  
Heat Affected Zone ◽  
Welding Process ◽  
Weld Bead ◽  
Welding Parameters ◽  
Process Conditions ◽  
Multi Objective Optimization ◽  
Depth Of Penetration ◽  
Control Variables ◽  
Bead Width ◽  
Multi Objective

The selection of optimal welding parameters in any welding process significantly improves the quality, production rate, and cost of a component. The weld bead characteristics such as bead width, depth of penetration, and heat-affected zone are the prominent factors for evaluating the performance of a welded joint. The work presents a novel evolutionary multi-objective optimization approach to derive the optimal laser welding conditions for the weld bead geometrical parameters. The welding experiments were conducted with the consideration of pulse frequency, pulse width, welding speed, and pulse energy as the process-control variables to evaluate the weld bead characteristics. Empirical models for the bead characteristics were developed in terms of the input variables using response surface methodology. The individual and interactive effects of the variables on the responses were also analyzed. As the influence of control variables on the bead characteristics is conflicting in nature, the problem is formulated as a multi-objective optimization problem to simultaneously optimize the output parameters. The aim is to simultaneously minimize the bead width, maximize the depth of penetration, and minimize the heat-affected zone. An efficient evolutionary algorithm called non-dominated sorting genetic algorithm-II was applied to derive the set of Pareto-optimal solutions. The derived optimal process responses were confirmed with the experimental values. The proposed integrated methodology can be applied to any welding process to automate the process conditions in computer-integrated manufacturing environment.

scholarly journals APLICAÇÃO DO MÉTODO DMAIC PARA MELHORIA NO PROCESSO DE SOLDA LASER NA INDÚSTRIA AUTOMOTIVA

2019 ◽  
Vol 10 (2) ◽  
pp. 03
Author(s):  
Luiz Ricardo De Paiva ◽  
Michael Fidelis da Cruz ◽  
Rodrigo Otávio Venturini Salamão ◽  
Luís De Souza Sanchez ◽  
Erika Peterson Gonçalves
Keyword(s):  
Laser Beam ◽  
Automotive Industry ◽  
Heat Affected Zone ◽  
Energy Supply ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Weld Bead ◽  
Robotic Systems ◽  
Welding Wire ◽  
Root Cause

A soldagem a laser é amplamente utilizada na indústria automotiva, pois apresenta qualidade no acabamento, aporte de energia e redução da zona afetada pelo calor. No entanto, a limitação quanto à espessura do cordão de solda, instabilidade no foco do laser e a dificuldade em guiá-lo para a região de soldagem exigem sistemas robotizados de alta precisão para a aplicação de maneira adequada. O processo na unidade fabril em questão é totalmente robotizado, porém, apresentou instabilidade durante a soldagem, resultando em falhas no cordão e desgaste prematuro dos bicos de soldagem. Este trabalho, por meio da metodologia DMAIC, estabeleceu a correlação entre as falhas no cordão de solda, troca excessiva dos bicos e cast do arame de soldagem. Foi determinada a causa raiz do problema e propôs-se soluções viáveis, as quais foram implementadas. A partir dessas ações na empresa automotiva, foi possível reduzir o consumo de bicos em 60% durante o processo de soldagem, permitindo manter o índice de falhas abaixo de 0,6 a cada mil unidades inspecionadas.Palavras-chave: DMAIC. Soldagem a Laser. Indústria Automotiva.ABSTRACTLaser welding is widely used in the automotive industry, because it offers quality in finishing, energy supply and reduction of the heat affected zone. However, limiting the thickness of the weld bead, instability in the focus of the laser and the difficulty in guiding it to the welding region, requires high-precision robotic systems for proper application. The process in the industry in question is totally robotized, but it showed instability during welding, resulting in cord failure and premature wear of the welding nozzles. This work, through the DMAIC methodology, established the correlation between weld bead failures, excessive nozzle exchange and cast welding wire. The root cause of the problem was determined and viable solutions were proposed and implemented. From these actions in the automotive industry it was possible to reduce the nozzle consumption by 60% during the welding process, allowing to keep the failure rate below 0.6 per thousand inspected units.Keywords: DMAIC. Laser Beam Welding. Automotive Industry.

Influence of Thermal Simulated and Real Tandem Submerged Arc Welding Process on the Microstructure and Mechanical Properties of the Coarse Grained Heat Affected Zone

2011 ◽  
Vol 110-116 ◽  
pp. 3191-3198
Author(s):  
Sadegh Moeinifar
Keyword(s):  
Grain Boundaries ◽  
Heat Affected Zone ◽  
Heat Input ◽  
Arc Welding ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Rolled Plate ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Tandem Submerged Arc Welding

The high-strength low-alloy microalloyed steel was procured as a hot rolled plate with accelerated cooling. The Gleeble thermal simulated process involved heating the steel specimens to the peak temperature of 1400 °C, with constant cooling rates of 3.75 °C/s and 2 °C/s to room temperature. The four-wire tandem submerged arc welding process, with different heat input, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat affected zone regions. The martensite/austenite constituents were obtained by a combination of field emission scanning electron microscopes and image analysis software The Charpy absorbed energy of specimens was assessed using Charpy impact testing at-50 °C. Brittle particles, such as martensite/austenite constituent along the grain boundaries, can make an easy path for crack propagation. Similar crack initiation sites and growth mechanism were investigated for specimens welded with different heat input values.

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 Validation of Welding Simulations Using Thermal Strains Measured with DIC

2011 ◽  
Vol 70 ◽  
pp. 129-134 ◽  
Author(s):  
Maarten De Strycker ◽  
Pascal Lava ◽  
Wim Van Paepegem ◽  
Luc Schueremans ◽  
Dimitri Debruyne
Keyword(s):  
Residual Stresses ◽  
Cross Section ◽  
Circular Cross Section ◽  
Welding Process ◽  
Weld Bead ◽  
Image Correlation ◽  
Steel Tubes ◽  
Element Analysis ◽  
Strain Evolution ◽  
The Cross

Residual stresses can affect the performance of steel tubes in many ways and as a result their magnitude and distribution is of particular interest to many applications. Residual stresses in cold-rolled steel tubes mainly originate from the rolling of a flat plate into a circular cross section (involving plastic deformations) and the weld bead that closes the cross section (involving non-uniform heating and cooling). Focus in this contribution is on the longitudinal weld bead that closes the cross section. To reveal the residual stresses in the tubes under consideration, a finite element analysis (FEA) of the welding step in the production process is made. The FEA of the welding process is validated with the temperature evolution of the thermal simulation and the strain evolution for the mechanical part of the analysis. Several methods for measuring the strain evolution are available and in this contribution it is investigated if the Digital Image Correlation (DIC) technique can record the strain evolution during welding. It is shown that the strain evolution obtained with DIC is in agreement with that found by electrical resistance strain gauges. The results of these experimental measuring methods are compared with numerical results from a FEA of the welding process.

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