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Article
Publication date: 4 July 2016

Chuan Liu, Ying Luo, Min Yang and Qiang Fu

The purpose of this paper is to clarify the effect of material hardening model and lump-pass method on the thermal-elastic-plastic (TEP) finite element (FE) simulation of…

Abstract

Purpose

The purpose of this paper is to clarify the effect of material hardening model and lump-pass method on the thermal-elastic-plastic (TEP) finite element (FE) simulation of residual stress induced by multi-pass welding of materials with cyclic plasticity.

Design/methodology/approach

Nickel-base alloy and stainless steel, which are used in J-type weld for manufacturing the nuclear reactor pressure head, can easily harden during multi-pass welding. The J-weld welding experiment is carried out and the temperature cycle and residual stress are measured to validate the TEP simulation. Thermal-mechanical sequence coupling method is employed to get the welding residual stress. The lumped-pass model and pass-by-pass FE model are built and two materials hardening models, kinematic hardening model and mixed hardening model, are adopted during the simulations. The effects of material hardening models and lumped-pass method on the residual stress in J-weld are distinguished.

Findings

Based on the kinematic hardening model, the stresses simulated with the lumped-pass FE model are almost consistent with those obtained by the pass-by-pass FE model; while with the mixed hardening material model, the lumped-pass method has great effect on the simulated stress.

Practical implications

A computation with mixed isotropic-kinematic material seems not to be the appropriate solution when using the lumped-pass method to save the computation time.

Originality/value

In the simulation of multi-pass welding residual stress involved in materials with cyclic plasticity, the material hardening model should be carefully considered. The kinematic hardening model with lump-pass FE model can be used to get better simulation results with less computation time. The results give a direction for welding residual stress simulation for the large structure such as the reactor pressure vessel.

Details

Engineering Computations, vol. 33 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 25 September 2009

Mumin Sahin

The purpose of this paper is to investigate mechanical and metallurgical variations at interfaces of commercial austenitic‐stainless steel and copper materials welded by…

Abstract

Purpose

The purpose of this paper is to investigate mechanical and metallurgical variations at interfaces of commercial austenitic‐stainless steel and copper materials welded by friction welding.

Design/methodology/approach

In this paper, austenitic‐stainless commercial steel and copper materials are welded using the friction welding method. The optimum parameters are obtained for the joints. The joints are applied to the tensile and micro‐hardness tests. Then, micro‐ and macro‐photos of the joints are examined.

Findings

It is found that some of the welds show poor strength depending on some accumulation of alloying elements at the interface result of temperature rise and the existence of intermetallic layers.

Research limitations/implications

It would be interesting to search about the toughness values and fatigue behaviour of the joints. It could be a good idea for future work to concentrate on the friction welding of these materials.

Practical implications

Friction welding can be achieved at high‐production rates and therefore is economical in operation. In applications where friction welding has replaced other joining processes, the production rate has been increased substantially.

Originality/value

The main value of this paper is to contribute to the literature on friction welding of dissimilar materials.

Details

Industrial Lubrication and Tribology, vol. 61 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 2 February 2015

A. Krasovskyy and A. Virta

Even though modern welding technology has improved, initial defects on weld notches cannot be avoided. Assuming the existence of crack-like flaws after the welding

Abstract

Purpose

Even though modern welding technology has improved, initial defects on weld notches cannot be avoided. Assuming the existence of crack-like flaws after the welding process, the stage of a fatigue crack nucleation becomes insignificant and the threshold for the initial crack propagation can be used as a criterion for very high cycle fatigue whereas crack growth analysis can be applied for the lifetime estimation at lower number of cycles. The purpose of this paper is to present a mechanism based approach for lifetime estimation of welded joints, subjected to a multiaxial non-proportional loading.

Design/methodology/approach

The proposed method, which is based on the welding process simulation, thermophysical material modeling and fracture mechanics, considers the most important aspects for fatigue of welds. Applying worst-case assumptions, fatigue limits derived by the weight function method can be then used for the fatigue assessment of complex welded structures.

Findings

An accurate mechanism based method for the fatigue life assessment of welded joints has been presented and validated.

Originality/value

Compared to the fatigue limits provided by design codes, the proposed method offers more accurate lifetime estimation, a better understanding of interactions between welding process and fatigue behavior. It gives more possibilities to optimize the welding process specifically for the considered material, weld type and loading in order to achieve the full cost and weight optimization potential for industrial applications.

Details

International Journal of Structural Integrity, vol. 6 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 June 1995

Leif Karlsson

Duplex stainless steels have become important competitors to austenitic stainless steels in many applications and a great deal of attention has focused on the welding

Abstract

Duplex stainless steels have become important competitors to austenitic stainless steels in many applications and a great deal of attention has focused on the welding aspects. The introduction of modern grades with improved properties and a competitive price level have increased their use in the offshore, petrochemical and shipbuilding industries, for example. In particular the newer grades, with their higher nitrogen content and improved weldability, have moved duplex stainless steels from a position as “interesting” materials to one of “useful in practice”. However, duplex stainless steels differ from austenitic grades in some respects, and know‐how combined with the use of appropriate welding procedures and consumables is therefore the key to successful welding.

Details

Anti-Corrosion Methods and Materials, vol. 42 no. 6
Type: Research Article
ISSN: 0003-5599

Article
Publication date: 5 May 2015

Mica Grujicic, Subrahmanian Ramaswami, Jennifer Snipes, Rohan Galgalikar, Ramin Yavari, Chian-Fong Yen, Bryan Cheeseman and Jonathan Montgomery

The purpose of this paper is to discuss the recently developed multi-physics computational model for the conventional Gas Metal Arc Welding (GMAW) joining process that has…

Abstract

Purpose

The purpose of this paper is to discuss the recently developed multi-physics computational model for the conventional Gas Metal Arc Welding (GMAW) joining process that has been upgraded with respect to its predictive capabilities regarding the spatial distribution of the mechanical properties controlling the ballistic limit (i.e. penetration resistance) of the weld.

Design/methodology/approach

The original model consists of five modules, each dedicated to handling a specific aspect of the GMAW process, i.e.: electro-dynamics of the welding-gun; radiation-/convection-controlled heat transfer from the electric arc to the workpiece and mass transfer from the filler-metal consumable electrode to the weld; prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; and spatial distribution of the as-welded material mechanical properties. The model is upgraded through the introduction of the sixth module in the present work in recognition of the fact that in thick steel GMAW weldments, the overall ballistic performance of the armor may become controlled by the (often inferior) ballistic limits of its weld (fusion and heat-affected) zones.

Findings

The upgraded GMAW process model is next applied to the case of butt-welding of MIL A46100 (a prototypical high-hardness armor-grade martensitic steel) workpieces using filler-metal electrodes made of the same material. The predictions of the upgraded GMAW process model pertaining to the spatial distribution of the material microstructure and ballistic-limit-controlling mechanical properties within the MIL A46100 butt-weld are found to be consistent with general expectations and prior observations.

Originality/value

To the authors’ knowledge, the present work is the first reported attempt to establish, using computational modeling, functional relationships between the GMAW process parameters and the mechanical properties controlling the ballistic limit of the resulting weld.

Details

Engineering Computations, vol. 32 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 16 March 2020

Nagabhushan Kumar Kadigithala and Vanitha C

The main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm…

Abstract

Purpose

The main purpose of the present work is to evaluate, the microstructural and mechanical properties of friction stir welded plates of AZ91D magnesium alloy with 3 mm thickness, and to determine the optimum range of welding conditions.

Design/methodology/approach

Microstructure and fractographic studies were carried out using scanning electron microscopy (SEM). Vickers micro hardness test was performed to evaluate the hardness profile in the region of the weld area. The phases in the material were confirmed by X-Ray diffraction (XRD) analysis. Transverse tensile tests were conducted using universal testing machine (UTM) to examine the joint strength of the weldments at different parameters.

Findings

Metallographic studies revealed that each zone shown different lineaments depending on the mechanical and thermal conditions. Significant improvement in the hardness was observed between the base material and weldments. Transverse tensile test results of weldments had shown almost similar strength that of base material regardless of welding speed. Fractographic examination indicated that the welded specimens failed due to brittle mode fracture. Through these studies it was confirmed that friction stir welding (FSW) can be used for the welding of AZ91D magnesium alloy.

Research limitations/implications

In the present study, the welding speed varied from 25 mm/min to 75 mm/min, tilt angle varied from 1.5° to 2.5° and constant rotational speed of 500 rpm.

Practical implications

Magnesium and aluminum based alloys which are having high strength and low density, used in automotive and aerospace applications can be successfully joined using FSW technique. The fusion welding defects can be eliminated by adopting this technique.

Originality/value

Limited work had been carried out on the FSW of magnesium based alloys over aluminum based alloys. Furthermore, this paper analyses the influence of welding parameters over the microstructural and mechanical properties.

Details

International Journal of Structural Integrity, vol. 11 no. 6
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 November 2006

Ilyas Uygur

To provide information about technical data; wear behaviour of worn rotor parts in mining industry and for the other application of ferrous alloys.

1108

Abstract

Purpose

To provide information about technical data; wear behaviour of worn rotor parts in mining industry and for the other application of ferrous alloys.

Design/methodology/approach

Wear behaviour of the various filler wires were tested (tensile, hardness, and wear) and compared with each other in the light of microstructure, chemical, and mechanical properties.

Findings

The results showed that the wear rates were significantly increased with the increasing load, welding current, wear distance and poor mechanical properties. A larger amount of C, Cr, and Mn specimen showed the best wear resistance since it contained a number of hard MC‐type carbides and coarse grains. Furthermore, for all materials the weight loss increases linearly with the increasing of welding arc current, load and wear distance.

Research limitations/implications

It would be interesting to search about the toughness values and fatigue behaviour of these materials. It could be the good idea for future work could be concentrated fracture surface analysis of these materials.

Practical implications

For these materials choosing the right chemical composition of the filler material, certain arc current and ideal microstructure is crutial for the wear response.

Originality/value

The main value of this paper is to contribute and fulfil the mechanical properties of welding wires that is being studied so far in the literature such as the effects of chemical composition, applied road range, and arc current on the tensile, hardness and wear behaviours of the welding wires.

Details

Industrial Lubrication and Tribology, vol. 58 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 12 October 2012

Jeroen De Backer, Anna‐Karin Christiansson, Jens Oqueka and Gunnar Bolmsjö

Friction stir welding (FSW) is a novel method for joining materials without using consumables and without melting the materials. The purpose of this paper is to present…

Abstract

Purpose

Friction stir welding (FSW) is a novel method for joining materials without using consumables and without melting the materials. The purpose of this paper is to present the state of the art in robotic FSW and outline important steps for its implementation in industry and specifically the automotive industry.

Design/methodology/approach

This study focuses on the robot deflections during FSW, by relating process forces to the deviations from the programmed robot path and to the strength of the obtained joint. A robot adapted for the FSW process has been used in the experimental study. Two sensor‐based methods are implemented to determine path deviations during test runs and the resulting welds were examined with respect to tensile strength and path deviation.

Findings

It can be concluded that deflections must be compensated for in high strengths alloys. Several strategies can be applied including online sensing or compensation of the deflection in the robot program. The welding process was proven to be insensitive for small deviations and the presented path compensation methods are sufficient to obtain a strong and defect‐free welding joint.

Originality/value

This paper demonstrates the effect of FSW process forces on the robot, which is not found in literature. This is expected to contribute to the use of robots for FSW. The experiments were performed in a demonstrator facility which clearly showed the possibility of applying robotic FSW as a flexible industrial manufacturing process.

Details

Industrial Robot: An International Journal, vol. 39 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 July 1935

H. Sutton

WELDING has been employed in the manufacture of aircraft parts in Great Britain for some considerable time, and the use of welding has in recent years increased both as…

Abstract

WELDING has been employed in the manufacture of aircraft parts in Great Britain for some considerable time, and the use of welding has in recent years increased both as regards the amount of welding and the scope of application.

Details

Aircraft Engineering and Aerospace Technology, vol. 7 no. 7
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 5 August 2014

M. Grujicic, J.S. Snipes, R. Galgalikar, S. Ramaswami, R. Yavari, C.-F. Yen, B.A. Cheeseman and J.S. Montgomery

The purpose of this paper is to develop multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process has been improved with respect…

Abstract

Purpose

The purpose of this paper is to develop multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process has been improved with respect to its predictive capabilities regarding the spatial distribution of the mechanical properties (strength, in particular) within the weld.

Design/methodology/approach

The improved GMAW process model is next applied to the case of butt-welding of MIL A46100 (a prototypical high-hardness armor-grade martensitic steel) workpieces using filler-metal electrodes made of the same material. A critical assessment is conducted of the basic foundation of the model, including its five modules, each dedicated to handling a specific aspect of the GMAW process, i.e.: first, electro-dynamics of the welding-gun; second, radiation/convection controlled heat transfer from the electric arc to the workpiece and mass transfer from the filler-metal consumable electrode to the weld; third, prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; fourth, the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; and fifth, spatial distribution of the as-welded material mechanical properties.

Findings

The predictions of the improved GMAW process model pertaining to the spatial distribution of the material microstructure and properties within the MIL A46100 butt-weld are found to be consistent with general expectations and prior observations.

Originality/value

To explain microstructure/property relationships within different portions of the weld, advanced physical-metallurgy concepts and principles are identified, and their governing equations parameterized and applied within a post-processing data-reduction procedure.

Details

Multidiscipline Modeling in Materials and Structures, vol. 10 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

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