Determination of stability of MIG/MAG welding processes

2001 ◽  
Vol 17 (5) ◽  
pp. 345-353
Author(s):  
Marjan Suban
Keyword(s):  
Mag Welding ◽  
Welding Processes

Multi-Tier Tensile Strain Models for Strain-Based Design: Part 2 — Development and Formulation of Tensile Strain Capacity Models

2012 ◽  
Author(s):  
Ming Liu ◽  
Yong-Yi Wang ◽  
Yaxin Song ◽  
David Horsley ◽  
Steve Nanney
Keyword(s):  
Driving Force ◽  
Tensile Strain ◽  
Weld Strength ◽  
Experiment Data ◽  
Pipe Wall Thickness ◽  
Crack Driving Force ◽  
Strain Capacity ◽  
Welding Processes ◽  
Tensile Strain Capacity

This is the second paper in a three-paper series related to the development of tensile strain models. The fundamental basis of the models [1] and evaluation of the models against experiment data [2] are presented in two companion papers. This paper presents the structure and formulation of the models. The philosophy and development of the multi-tier tensile strain models are described. The tensile strain models are applicable for linepipe grades from X65 to X100 and two welding processes, i.e., mechanized GMAW and FCAW/SMAW. The tensile strain capacity (TSC) is given as a function of key material properties and weld and flaw geometric parameters, including pipe wall thickness, girth weld high-low misalignment, pipe strain hardening (Y/T ratio), weld strength mismatch, girth weld flaw size, toughness, and internal pressure. Two essential parts of the tensile strain models are the crack driving force and material’s toughness. This paper covers principally the crack driving force. The significance and determination of material’s toughness are covered in the companion papers [1,2].

Determination of Heat Input in Tungsten Inert Gas and Laser Welding of Type Optim 960 QC Structural Steel Using Adams’ Equation for 2-D Heat Distribution

2017 ◽  
Vol 750 ◽  
pp. 45-52
Author(s):  
Sveto Cvetkovski
Keyword(s):  
Laser Welding ◽  
Heat Input ◽  
Arc Welding ◽  
Research Work ◽  
Laser Beam Welding ◽  
Peak Temperature ◽  
Efficiency Coefficient ◽  
Zone Recrystallization ◽  
Welding Processes

The heat input during conventional arc welding processes can be readily calculated knowing the power taken from the power source. The efficiency coefficient can be taken from the appropriate literature standards. Here, the intention of the performed research work was to develop a procedure for determination of heat input in arc and laser welding processes implementing Adams equation - modified Rykalin equation for two dimensional heat distributions (2-D). To realize this idea, it is necessary to determine two characteristic temperatures points in the HAZ with known peak temperature, and to determine distance between them. Implementing measured values for distance in Adams’ equation, heat input in arc welding can be directly determined in arc welded joints.In laser beam welding, the absorption of the beam in the metal is not known, so that the welding heat input cannot be calculated directly, and direct implementation of Adam’s equation is not possible i.e. absorption coefficient has to be determined first, and after that calculation of heat input is possible.The peak temperatures corresponding to specific microstructures can be obtained by performing welding simulation, by the Gleeble 1500 simulator in our case. As one of the peak temperatures, the melting temperature can be used corresponding to the fusion line, so that at least one characteristic peak temperature such as coarse grain zone, fine grin zone, intercritical zone, recrystallization, has to be determined by the simulation.Performed research showed that obtained values for heat input using Adam’s equation correspond pretty well with standard equation for heat input in arc welding.

scholarly journals Monitoring of the process of Flash-Butt Welding

2013 ◽  
Vol 18 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Yevgenia Chvertko ◽  
Mykola Shevchenko ◽  
Andriy Pirumov
Keyword(s):  
Neural Networks ◽  
Real Time ◽  
Statistical Methods ◽  
Welded Joints ◽  
Welding Parameter ◽  
Monitoring Systems ◽  
Butt Welding ◽  
On Line ◽  
Welding Processes

Statistical methods of analysis are currently widely used to develop control and monitoring systems for different welding processes. These methods allow to obtain information about the process including effect of all factors on its results, which is often difficult to evaluate due to the complexity of the process. The authors made efforts to apply these methods to develop the system for monitoring the parameters of flash-butt welding in real-time mode. The paper gives brief information about the features of flash-butt welding of reinforcement bars and some basic limitation of this process application. The main reasons of formation of defects in welded joints are given as well as analysis of possibility of application of monitoring systems for their determination. The on-line monitoring system based on neural networks was developed for evaluation of process deviations. This system is believed to be adequate for determination of process violations resulting in disturbances of welding parameter and can be used for prediction of possible defects in the welded joints.

scholarly journals The Use of Arc Welding Processes in the Additive Manufacturing of Metallic Products

2020 ◽  
pp. 43-48
Author(s):  
Krzysztof Pańcikiewicz
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Maraging Steel ◽  
Arc Welding ◽  
Mag Welding ◽  
Unalloyed Steels ◽  
Manufactured Products ◽  
Welding Processes ◽  
Unalloyed Steel

The article presents examples of additive manufactured products obtained using MIG /MAG welding processes (13). The research-related tests revealed that it is possible to make products of unalloyed steels having the structure similar to castings subjected to heat treatment. Products made of maraging steel require homogenising (heat treatment). It is possible to produce bimetallic products, e.g. unalloyed steel-bronze.

Residual Stresses Evaluation on Radial Friction Welded Joints

2005 ◽  
Author(s):  
Rosa Irene Terra Pinto ◽  
Telmo Roberto Strohaecker
Keyword(s):  
Residual Stresses ◽  
Friction Welding ◽  
Deformation Gradient ◽  
Welding Process ◽  
Hole Drilling ◽  
Welding Parameters ◽  
Hole Drilling Method ◽  
Joint Quality ◽  
Welding Processes

The Radial Friction Welding (RFW) is a solid-state welding process in which two long elements of several metallic alloys can be joined, without the occurrence of common problems to the conventional welding processes that include fusion. During friction welding the temperature evolution is directly related with the deformation gradient, and these fields govern the joint properties. In this work, the finite element method was used to solve the full coupled termomechanical problem in order to determine the deformation and the stress fields and the variation of the temperature during RFW process. The simulation of the RFW process permitted to establish the influence of the welding parameters, like rotation and approximation speed, on the joint quality. Furthermore, the knowledge of the temperature gradient and cooling rates allowed the prediction of the resulting microestruture and determination of the level of residual stresses of the joint. To verify the analytical results the determination of the residual stresses was accomplished by the hole drilling method in several points along the perimeter of two welded workpieces.

Chromium(VI) compounds – inhalable fraction. Determining in workplace air with ionic chromatography

2018 ◽  
Vol 35 (3(97)) ◽  
pp. 17-34
Author(s):  
Małgorzata Szewczyńska ◽  
Małgorzata Pośniak
Keyword(s):  
Limit Of Detection ◽  
Selective Determination ◽  
Chromium Vi ◽  
Nasal Cancer ◽  
Workplace Air ◽  
Chromium Compounds ◽  
Welding Processes ◽  
Ionic Chromatography

The metallurgical, mining and tanning industries are, among others, very important sources of chromium compounds emission to the environment. Moreover, chromium is widely used in the production of dyes, pigments, paints and wood preservatives. Welding processes are one of the sources of exposure to chromium compounds under occupational conditions. Long-term occupational exposure to Cr(VI) chromium compounds increases the risk of developing lung or nasal cancer. The aim of the study was to develop a method for selective determination of Cr(VI) compounds in the workplace air with a combination of ion chromatography technique and post-column derivatisation. The method is based on separating the inhalable fraction of chromium(VI) compounds on a filter using an I.O.M. type probe, extraction with 10 mL of 2% sodium hydroxide/3% sodium carbonate solution and further analysis with ionic chromatography with a post-column reaction of Cr(VI) with 1.5-diphenyl carbazide (DPC) and spectrophotometric determination of the formed Cr(VI)-DPC complex. The measuring range for chromium (VI) compounds is 0.072–1.44 µg/mL. Precision, chromium recovery from filters, limit of detection and quantification were calculated. The overall uncertainty was 12.2 %. The expanded uncertainty for Cr(VI) was 24.3%. The developed method enables the separation and quantification of Cr(VI) compounds in the presence of Cr(III) compounds in air samples (avoiding adverse reactions of one form of chromium to another) at a level of 0.0009 mg/m3 for Cr(VI) compounds converted into Cr at 720-L intake of air. The procedure for determining chromium(VI) compounds is included in the annex.

Numerical simulation of welding-induced residual stress in fusion welding process using adaptive volumetric heat source

2014 ◽  
Vol 228 (16) ◽  
pp. 2960-2972 ◽  
Author(s):  
S Singh ◽  
N Yadaiah ◽  
S Bag ◽  
S Pal
Keyword(s):  
Residual Stress ◽  
Numerical Model ◽  
Heat Source ◽  
Measurement Errors ◽  
High Performance ◽  
Welding Process ◽  
Fusion Welding ◽  
Volumetric Heat Source ◽  
Welding Processes

The mechanical properties of a weldment structure are influenced by the level of residual stress generated during fusion welding process. The experimental determination of residual stress is cumbersome and not free from measurement errors. A sophisticated numerical model is relatively easy approach to predict residual stress due to the advancement of high performance computational technology. However, the integration of all process physics to make a sophisticated numerical model is ever demanding. The present work is motivated in that direction and involves a finite element based numerical model for simulation of welding-induced residual stresses. A thermal model using adaptive volumetric heat source has been used to estimate temperature distribution. Subsequently, the thermal history is used to perform stress analysis for butt welded plates using three different fusion welding processes. The material behaviour is assumed as elasto-plastic in nature. The calculated results and their trend have been validated with experimental results available in open literature.

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