Determination of some Mechanical Characteristics by Vibration Testing of Welded Structures with Tubular Wire

2013 ◽  
Vol 814 ◽  
pp. 127-134 ◽  
Author(s):  
Liviu Bereteu ◽  
Raul Moisa ◽  
Mihaela Popescu ◽  
Gheorghe Drăgănescu ◽  
Radu Alexandru Rosu ◽  
...  
Keyword(s):  
Steel Wire ◽  
Welding Process ◽  
Tensile Tests ◽  
Operating Conditions ◽  
Steel Plates ◽  
Vibration Testing ◽  
Welded Structures ◽  
Appropriate Behavior ◽  
Welded Structure

Applicability of the welded structures in different operating conditions requires experimental research developed in conditions previously imposed for each punctual application. There are analyzed in this case, in terms of vibration testing, some welded joints made with usual tubular steel wire. This is the case of the type carbon steel plates S235 JR according to EN 10025, with a thickness of 3 mm welded with MIG/MAG welding process with R713 tubular wire with a diameter of 1.2 mm, using SelcoNeoMig 3500 equipment. By processing the received signal based on the vibrations response to determine the elastic modulus of the welded structure, which will then be compared both with the modulus value obtained by tensile tests, and with the theoretical value obtained. The results thus obtained will be the basis of design, in optimal conditions of the welded structures regarding the appropriate behavior to the demands imposed.

scholarly journals Determination of Strain and Stress Fields in Welded Joints of S960-QC Steel

2017 ◽  
Vol 62 (4) ◽  
pp. 2081-2087 ◽  
Author(s):  
T. Pała ◽  
I. Dzioba
Keyword(s):  
Welded Joints ◽  
Experimental Studies ◽  
Welding Process ◽  
Tensile Tests ◽  
Stress Fields ◽  
Uniaxial Tensile ◽  
Displacement Fields ◽  
The Individual ◽  
Computational Part

Abstract The paper presents the results of two butt welded joints by conventional method. The welding process was performed using a variety of linear welding energy. The studies included experimental and computational part. In experimental studies determined the distribution of hardness and mechanical properties of the individual analyzed sections of welded joints. The data obtained were intended to determine the extent of zones in the welded joints that have certain strength characteristics. Also conducted uniaxial tensile tests of welded joints with the registration of displacement fields on the surface of specimens by means of Aramis video-system what the final result are images of strain fields map on the surface of welded joints. The resulting strain values were compared with the results of numerical computations FEM.

Computation of HAZ Hardness for Low Alloyed Welded Steels Using Five-Parameter Logistic Function

2014 ◽  
Vol 216 ◽  
pp. 103-109
Author(s):  
Marius Bodea ◽  
Radu Mureşan
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Chemical Composition ◽  
Heat Flow ◽  
Welding Process ◽  
Logistic Function ◽  
Steel Plates ◽  
Maximum Hardness ◽  
Welded Structures ◽  
Asymmetric Data

The mechanical properties of the welded structures are directly related to the weldability of the steels, thus the estimation of the microstructural constituents in the weld and maximum hardness in the HAZ according to the welding process parameters represent a problem of great interest. The microstructural changes in the HAZ are estimated using a five-parameter logistic function (5PL), which is very accurate in the fitting highly asymmetric data. Also, the same 5PL function can be used in order to predict hardness and toughness in the HAZ based on the heat flow, cooling rates between 800-500 oC and chemical composition of the material. A discussion about the parameters of the 5PL function and fitting experimental data is presented and a studied case for welding S355J2 steel plates is also analyzed.

Coupled Field Analysis of a Gas Tungsten Arc Welded Butt Joint—Part I: Improved Modeling

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
D. Sen ◽  
M. A. Pierson ◽  
K. S. Ball
Keyword(s):  
Weld Pool ◽  
Welding Process ◽  
Butt Joint ◽  
Accurate Estimation ◽  
Mathematical Framework ◽  
Welded Structures ◽  
Thermally Induced ◽  
Gas Tungsten Arc ◽  
Welded Structure ◽  
Gas Tungsten

Thermally induced residual stresses due to welding can significantly impair the performance and reliability of welded structures. From a structural integrity perspective of welded structures, it is necessary to have an accurate spatial and temporal thermal distribution in the welded structure before stress analysis is performed. Existing research has ignored the effect of fluid flow in the weld pool on the temperature field of the welded joint. Previous research has established that the weld pool depth/width (D/W) ratio and heat affected zone (HAZ) are significantly altered by the weld pool dynamics. Hence, for a more accurate estimation of the thermally induced stresses it is desired to incorporate the weld pool dynamics into the analysis. Moreover, the effects of microstructure evolution in the HAZ on the mechanical behavior of the structure need to be included in the analysis for better mechanical response prediction. In this study, a three-dimensional numerical model for the thermomechanical analysis of gas tungsten arc (GTA) welding of thin stainless steel butt-joint plates has been developed. The model incorporates the effects of thermal energy redistribution through weld pool dynamics into the structural behavior calculations. Through material modeling the effects of microstructure change/phase transformation are indirectly included in the model. The developed weld pool dynamics model includes the effects of current, arc length, and electrode angle on the heat flux and current density distributions. All the major weld pool driving forces are included, namely surface tension gradient induced convection, plasma induced drag force, electromagnetic force, and buoyancy. The weld D/W predictions are validated with experimental results. They agree well. The workpiece deformation and stress distributions are also highlighted. The mathematical framework developed here serves as a robust tool for better quantification of thermally induced stress evolution and distribution in a welded structure by coupling the different fields in a welding process.

Vibration Tests for Determination of Longitudinal Elasticity Modulus and Shear Modulus of some Structures Welded with Tubular Wire

2013 ◽  
Vol 430 ◽  
pp. 101-107
Author(s):  
Raul Moisa ◽  
Tiberiu Medgyesi ◽  
Liviu Bereteu ◽  
Gheorghe Drăgănescu ◽  
Dorin Simoiu ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Shear Modulus ◽  
Elasticity Modulus ◽  
Welding Process ◽  
Flexural Vibration ◽  
Steel Plates ◽  
Welding Parameters ◽  
Advantages And Disadvantages ◽  
Vibration Tests

The purpose of this paper is to determine Young's modulus and the shear modulus of some welded joints made with usual tubular steel by flexural vibration tests. This is the case of the type carbon steel plates S235 JR according to EN 10025, with a thickness of 3 mm welded with MIG/MAG welding process with R713 tubular wire with a diameter of 1.2 mm, using SelcoNeoMig 3500 equipment. The technological part is detailed: welding parameters used, advantages and disadvantages of tubular wires use, problems regarding ambient protection, punctual applications of welding procedures with tubular wire. Processing the obtained signal based on vibration response the elasticity modulus is determined and its value is then compared with the value of elasticity modulus obtained through tensile stress and also with the value obtained by theoretical way.

Application of laser interferometry to the choice of processing modes by the criterion of the residual stress level

2020 ◽  
Vol 86 (2) ◽  
pp. 54-60
Author(s):  
K. E. Ponomaryev ◽  
I. V. Strelnikov ◽  
A. A. Antonov ◽  
A. A. Bondarenko
Keyword(s):  
Welding Process ◽  
Laser Interferometry ◽  
Welded Structures ◽  
Vibration Treatment ◽  
Digital Format ◽  
Processing Modes ◽  
Technological Processing ◽  
Arc Welding Process ◽  
Reliable Methods

Optimization of the modes of technological processing aimed at reduction or redistribution of residual stresses requires the use of modern and reliable methods of control. The method of laser interferometry leads to minor damages which are considered acceptable or can be easily removed. It is possible to use the method in industrial conditions of the workshops. Unlike physical methods, which have restrictions imposed on the classes and characteristics of materials in terms of structure, magnetic properties, and hardness, the method of laser interferometry exhibits a universal character. The method allows data saving in a digital format on speckle interferograms, thus providing a possibility of the traceability of measurement stages, expert comparison and reliable reporting. Laser interferometry provides determination of the absolute values of stresses with the error of the yield point measurement below 10%. The method can be successfully used to control the stress state in the production of critical welded structures from aluminum alloys, which are subject to stringent requirements for dimensional stability, accuracy and reliability. The technology of manufacturing the above welded structures usually includes vibration treatment, combined with the arc welding process. This technology, unlike heat treatment, is rather efficient, environmentally friendly, and low energy consumption process. Optimization of the technology plays a key role in the industrial implementation and can significantly reduce the economic costs of subsequent machining. The method of laser interferometry provides effective determination of the optimal technological mode by the parameter of residual post-welding stresses, as well as determination of the degree of the reduction of those stresses compared to the case without concomitant vibration treatment.

Failure Analysis of a Damaged Helicopter Rescue Hoist Cable

2012 ◽  
Vol 730-732 ◽  
pp. 325-330
Author(s):  
Teresa L.M. Morgado ◽  
Armando Sousa Brito ◽  
Carlos M. Branco
Keyword(s):  
Steel Wire ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Work Conditions ◽  
Fractographic Analysis ◽  
Ductile Mode ◽  
Cause Of Failure ◽  
Rescue Hoist

This paper presents the results and main conclusions of a study made to analyze the cause of failure occurred with an austenitic 304 class stainless steel wire rope of a helicopter rescue hoist. The cable is made up of 19 strands, 12 outside and 7 inside. As each strand contains 7 wires, the whole cable is made up of 133 wires. The study includes the chemical and microstructural characterization of the material, as well as the determination of its hardness, mechanical properties and the fractographic analysis by scanning electron microscopy (SEM). Tensile tests were performed for three velocities simulating different work conditions: 250mm/min, 50mm/min and 5mm/min. The fractographic analysis shows that the cable suffered lateral loss of material due to friction and leading to the failure of the remaining material by ductile mode.

Damage Detection in Flux Cored Wire Welded Structures by Using Vibration Testing

2014 ◽  
Vol 216 ◽  
pp. 110-115
Author(s):  
Alexandru Tocarciuc ◽  
Liviu Bereteu ◽  
Gheorghe Drăgănescu
Keyword(s):  
Structural Damage ◽  
Fatigue Cracks ◽  
Welding Process ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Post Processing ◽  
Acoustic Measurements ◽  
Cored Wire ◽  
Welded Structures ◽  
Vibration Responses

In welded structures subjected to dynamic cyclic loads may appear and propagate fatigue cracks due to local structural damage. These cracks may initiate due to technological damages induced by welding process, or by environmental operating conditions. In the present work, it is determined, by the means of Finite Element Method (FEM), the natural frequencies and mode shapes of more steel specimens that are welded together. The analysis is carried out in undamaged condition as well as in damaged one, after the damage has been artificially induced. The experimental measurement of the vibration response is carried out by using a condenser semi-professional microphone Samson C01U, which is suitable for high-fidelity acoustic measurements in the frequency range of 40 18.000 Hz. A first post-processing of the vibration responses of the welded specimens, in free-free conditions, is carried out using an algorithm based on Prony series. A second post-processing is carried out by means of signal processing using DWT together with Shannon entropy. The results are compared to modal parameters estimated using FE Analysis.

scholarly journals Treatment Analysis of Welding Structure in the Presence of a Crack Type Defects

2020 ◽  
Author(s):  
Mersida Manjgo ◽  
Meri Burzic
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Operating Conditions ◽  
Welded Structures ◽  
Treatment Analysis ◽  
New System

The largest number of welded structures in operating conditions is exposed to variable loads, which is why the share of fatigue fracture in the failure of welded structures is higher than others. The essence of construction with fracture safety is that the structure can withstand the designed load in the designed time. If a crack is detected during operation, it is possible to predict the development of damage during the service life as well as the load-bearing capacity of the structure depending on the development of damage. The paper describes a new system for monitoring fatigue crack growth, which is based on the change in the resistance of the measuring foil during crack growth. The system is compatible with the basic settings of the ASTM E647–86 standard, which refers to the determination of the fatigue crack growth rate.

scholarly journals Effects of Pre-Weld Heat Treatment and Heat Input on Metallurgical and Mechanical Behaviour in HAZ of Multi-Pass Welded IN-939 Superalloy

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1453
Author(s):  
Amirhossein Mashhuriazar ◽  
Hamid Omidvar ◽  
Zainuddin Sajuri ◽  
C. Hakan Gur ◽  
Amir Hossein Baghdadi
Keyword(s):  
Heat Treatment ◽  
Base Metal ◽  
Heat Input ◽  
Volume Fraction ◽  
Welding Process ◽  
Melting Zone ◽  
Tensile Tests ◽  
Operating Conditions ◽  
Inconel 625 ◽  
Tungsten Inert Gas Welding

Heat-affected zones (HAZs) of Inconel 939 (IN-939) superalloy are susceptible to cracking during welding process. Preventing cracking during the repair welding of turbine components is important. In this study, the effects of heat input and pre-welding heat treatment on the microstructure, mechanical properties and crack formation in tungsten inert gas welding of IN-939 were investigated. The whole specimens were welded using Inconel 625 filler in an Ar atmosphere and characterised by metallographic examinations and hardness measurements. Results showed that the microstructures of IN-939 HAZs were highly susceptible to cracking during welding due to increasing of γ′ volume fraction. All of these cracks appeared in the HAZs and grew perpendicular to the melting zone along the grain boundaries. In this survey, the pre-welding heat treatment and heat input strongly affected the HAZ microstructure and hardness. However, the pre-welding heat treatment with 67% impact was more effective than heat input with 30% impact. Finally, hot tensile tests were carried out on the specimens of the base metal and the optimal specimens under similar operating conditions within 600 °C–800 °C. Welding process did not affect the yield strength of the superalloy but slightly decreased its ultimate strength and elongation by as much as 92% and 50%, respectively, of those of the base metal.

scholarly journals The effect of laser stitch welding residual stress on the dynamic behaviour of thin steel structure

2019 ◽  
Vol 13 (4) ◽  
pp. 5780-5790
Author(s):  
M. A. S. Aziz Shah ◽  
M. A. Yunus ◽  
M. N. Abdul Rani ◽  
A. M. Saman ◽  
M. S. M. Sani ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Steel Structure ◽  
Welding Residual Stress ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Welded Structures ◽  
Welded Structure ◽  
Thin Steel

Laser stitch welding is one of the most reliable and efficient permanent metal joining processes in the automotive industry, particularly in the manufacturing of a car body-in-white (BIW). It is widely known that this welding process induces the generation of residual stresses that can influence the dynamic behaviours of welded structures. In order to accurately predict the dynamic behaviours of these welded structures, it is important to experimentally understand the influence of residual stress. Therefore, this study addresses the finite element modelling method of thin steel welded structures with and without the influences of residual stress in order to identify its effect towards dynamic behaviours. The finite element models of thin steel welded structures are developed by employing the area contact model (ACM2) format element connector.  The accuracy of the finite element models is then compared in terms of natural frequencies and mode shapes with the experimental counterparts. The dynamic behaviours of the measured structure are obtained using an impact hammer with free-free boundary conditions. The results demonstrate the importance of considering the influence of laser stitch welding residual stress in predicting the dynamic behaviours of thin steel welded structure.    

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