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The purpose of this paper is to examine the effects of the welding deformation and surface roughness in cold pressure welding on the tensile strength and the fatigue strength of joined sheets. Additionally, the paper seeks to analyse the hardness variations and microstructures at the welding interface.

Cold pressure welding is a method of joining similar or dissimilar ductile metals. It can be applied by bringing into close contact the surfaces of virgin metal specimens that appear due to the breakdown of the surface layers caused by bulk plastic deformation. Cold pressure welding is applied to test parts without too long a delay after the preparation of surfaces. The application of welding in 10 min affects importantly the weld strength. As this time is increased, the weld strength of the joints is decreased. The determination of deformation amount is found by determination of the reduction (R) at the total thickness of the two parts after the welding process.

The weld strength increases as the surface roughness and weld deformation of the joined sheets increase. The length of bond zones increases with increasing deformation. Therefore, the weld strength of parts depends on the length of bond zones. Then, there is an effect of surface roughness on the welding strength. Joined sheets show resistance to little fluctuating tensile stress. It is observed that the parts rupture from the welding‐interface hardness values are about the same at interfaces of sheets having different surface roughness and equal deformation (60 per cent). But, if it is considered that hardness of aluminium material purchased is about 53 HV, it can be said that the hardness increases in joined parts because of local hardening during deformation in cold pressure welding method as lap welding. Bond formation at interfaces of joined sheets having R_a=5 μm surface roughness and deformation ratio 60 per cent is shown to be successful in the microstructure photo.

Surface roughness and deformation values can be increased in further studies.

The paper offers insight into the effects of surface roughness on weldability.

The criteria importance through intercriteria correlation (CRITIC) and range of value (ROV) combined methods were used to determine a single index for all multiple responses.

This paper used cold metal transfer (CMT) and pulse metal-inert gas (MIG) welding processes to study the weld-on-bead geometry of AA2099-T86 alloy. This study used Taguchi's approach to find the optimal setting of the input welding parameters. The welding current, welding speed and contact-tip-to workpiece distance were the input welding parameters for finding the output responses, i.e. weld penetration, dilution and heat input. The L9 orthogonal array of Taguchi's approach was used to find out the optimal setting of the input parameters.

The optimal input welding parameters were determined with combined output responses. The predicted optimum welding input parameters were validated through confirmation tests. Analysis of variance showed that welding speed is the most influential factor in determining the weld bead geometry of the CMT and pulse MIG welding techniques.

The heat input and weld bead geometry are compared in both welding processes. The CMT welding samples show superior defect-free weld beads than pulse MIG welding due to lesser heat input and lesser dilution.

The present study seeks to examine the possibilities of combined usage of friction welding and plastic forming in recycling of bar‐shaped waste materials.

If the waste materials can be reproduced using various manufacturing methods without melting, their economic values could be increased economically. For this reason, using a combination of friction welding and plastic forming was chosen as an alternative recycling method. Upsetting was chosen as the plastic forming method due to its ease of application.

In the present study, dimensional changes, hardness variations in heat affected zone (HAZ), variations of torsion and tensile strengths with upsetting ratio of specimens were examined. Hardness values of test material are raised to higher levels within the HAZ by the local hardening. The maximum shear stress in torsion and the tensile strengths of specimens are closely harmonious with hardness values of test material.

Although it was observed in general that the increasing upsetting ratio increased the torsion and tensile strengths, experimental study must be improved and extended in order to obtain more precise results.

It can be concluded that combined usage of just welded and additional cold deformation can be considered as an alternative recycling method owing to obtained positive results.

This paper helps individuals reutilize waste materials because of the small lengths of the bars. Furthermore, it can be observed that the combination of friction welding and plastic forming produces savings in the material and the cost in this study.

Although the actual residual stress distribution in any structural steel member can be only obtained by experimental measurements, it is known to be a difficult, tedious and inefficient piece of work with limited accuracy. Thus, besides aiming at clarifying structural designers and researchers about the possible ways of modelling residual stresses when performing finite element analysis (FEA), the purpose of this paper is to provide an effective literature review of the longitudinal membrane residual stress analytical expressions for carbon steel non-heavy sections, covering a vast range of structural shapes (plates, I, H, L, T, cruciform, SHS, RHS and LSB) and fabrication processes (hot-rolling, welding and cold-forming).

This is a literature review.

Those residual stresses are those often required as input of numerical analyses, since the other types are approximately accounted for through the s-e curves of coupons cut from member walls.

One of the most challenging aspects in FEA aimed to simulate the real behaviour of steel members, is the modelling of residual stresses.

Besides aiming at clarifying structural designers and researchers about the possible ways of modelling residual stresses when performing FEA, this paper also provides an effective literature review of the longitudinal membrane residual stress analytical expressions for carbon steel non-heavy sections, covering a vast range of structural shapes (plates, I, H, L, T, cruciform, SHS, RHS and LSB) and fabrication processes (hot-rolling, welding and cold-forming).

The purpose of this paper is to study the wire and arc additive manufacturing (WAAM) method and path planning algorithm of truss structure parts, to realize the collision-free rapid prototyping of truss structures with complex characteristics.

First, a point-by-point stacking strategy is proposed based on the spot-welding mode of cold metal transfer welding technology. A force analysis model of the droplet is established, which can be used to adjust the posture of the welding torch and solve the collapse problem in the WAAM process of the truss structure. The collision detection model is developed to calculate the interference size between the truss structure and the welding torch, which is used to control the offset of the welding torch. Finally, the ant colony algorithm has been used to optimize the moving path of welding torch between truss with considering the algorithm efficiency and collision avoiding and the efficiency of the algorithm is improved by discretizing the three-dimensional workspace.

A series of experiments were conducted to prove the validity of the proposed methods. The results show that the wire feeding speed, welding speed are the important parameters for controlling the WAAM process of truss parts. The inclination angle of the welding torch has an important influence on the forming quality of the truss.

The force analysis model of truss structure in the WAAM process is established to ensure the forming quality and a collision-free path planning algorithm is proposed to improve forming efficiency.

This paper aims to examine dissimilar joints for various applications in chemical, petrochemical, oil, gas, shipbuilding, defense, rail and nuclear industry.

This study examined the effects of cold metal transfer welding on stainless steel welds for 316L austenitic and 430 ferritic dissimilar welds with ER316L, ER309L and without (autogenous) fillers. The microstructural observation was done with an optical microscope. The mechanical test was done to reveal the strength, hardness and toughness of the joint. The electrochemical polarization tests were done to reveal intergranular and pitting corrosion in the dissimilar joints.

This microstructural study shows the presence of austenitic and ferritic phases with vermicular ferrite for ER309L filler weld, and for ER316L filler weld specimen shows predominately martensitic phase in the weld region, whereas the autogenous weld shows lathy ferrite mixed with martensitic phase. Mechanical test results indicated that filler welded specimen (ER316L and ER309L) has relatively higher strength and hardness than the autogenous weld, whereas ER316L filler weld exhibited the highest impact toughness than ER309L filler weld and lowest in autogenous weld. The electrochemical corrosion results displayed the highest degree of sensitization (DOS) in without filler welded specimen (45.62%) and lower in case of filler welded specimen ER309L (4.95%) and least in case of ER316L filler welded specimen (3.51%). The high DOS in non-filler welded specimen is correlated with the chromium carbide formation. The non-filler welded specimen shows the highest pitting corrosion attack as compared to the ER316L filler weld specimen and relatively better in ER309L filler welded specimen. The highest pitting corrosion resistance is related with the high chromium content in ER309L composition.

This experimental study is original and conducted with 316L and 430 stainless steel with ER316L, ER309 and without fillers, which will help the oil, shipbuilding and chemical industries.

To highlight innovative welding technology exhibited at the Automatica exhibition in Munich.

Visited major companies participating at Automatica and spoke with them about important new developments.

New processes for welding thick and thin sheet were exhibited including novel applications for both the automotive industry and the heavy construction machinery sector.

Informs industry about new developments and potential benefits to be achieved.

A critical analysis of packaging and sealing methods for integrated circuits, hybrid microcircuits and multichip modules has been done. The best hermetic and high yield weld seal is examined along with other conventional seals like solder seal, frit seal and plastic seal with special emphasis on materials and processes involved in each case. An overview of emerging technology is also presented. A comparative analysis is made for selection of the right technology and material for a particular requirement.