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Low performance life and increased machine downtime due to wear of resistance welding copper electrode is of major concern in fin–tube resistance welding in waste heat recovery boilers. The purpose of this study is to investigate an alternative material with good wear resistance to replace the currently utilized C11000 electrolytic tough pitch (ETP) copper electrode.

In this study, a Cu-Cr-Zr ternary alloy was developed for fin-to-tube welding electrode by melting commercial grade electrolytic copper (99.9% purity) plates, chips of chromium, powder of zirconium at 1100°–1300°C, followed by hot forging and precipitation hardening at 450°–550°C to attain appropriate grain flow. Microstructures of Cu-Cr-Zr alloys were analysed using scanning electron microscopy coupled with energy-dispersive backscatter electron spectrometry.

Wear performance of Cu-Cr-Zr and C11000 ETP Cu was evaluated using pin-on-disc set-up with Taguchi’s L₈ orthogonal array. Ranking of the parameters was done, and it was observed that the material and temperature play a very significant role in controlling the wear of an electrode.

Rate of fin–tube resistance welding was increased by 26% with Cu-Cr-Zr alloy. Further investigation on effect of plasma on the metallurgical characteristics of Cu-Cr-Zr is recommended.

Tribo-mechanical performance of newly developed Cu-Cr-Zr ternary alloy was compared with C11000 ETP copper.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0092/

Recently, several studies have been performed on lap welding of aluminum and copper using friction stir welding (FSW). The formation of intermetallic compounds at the weld interface hampers the weld quality. The use of an intermediate layer of a compatible material during welding reduces the formation of intermetallic compounds. The purpose of this paper is to optimize the FSW process parameters for AA6063-ETP copper weld, using a compatible zinc intermediate filler metal.

In the present study, a three-level, three-factor central composite design (CCD) has been used to determine the effect of various process parameters, namely, tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil on ultimate tensile strength of the weld. A total of 60 experimental data were fitted in the CCD. The experiments were performed with tool rotational speeds of 1,000, 1,200 and 1,400 rpm each of them with tool traverse speeds of 5, 10 and 15 mm/min. A zinc inter-filler foil of 0.2 and 0.4 mm was also used. The macrograph of the weld surface under different process parameters and the tensile strength of the weld have been investigated.

The feasibility of joining 3 mm thick AA6063-ETP copper using zinc inter-filler is established. The regression analysis showed a good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R²) value of 0.9759 and model F-value of 240.33. A good agreement between the prediction model and experimental findings validates the reliability of the developed model. The tool rotational speed, tool traverse speed and thickness of inter-filler zinc foil significantly affected the tensile strength of the weld. The optimal conditions found for the weld were, rotational speed of 1,212.83 rpm and traverse speed of 9.63 mm/min and zinc foil thickness is 0.157 mm; by using optimized values, ultimate tensile strength of 122.87 MPa was achieved, from the desirability function.

Aluminium and copper sheets could be joined feasibly using a zinc inter-filler. The maximum tensile strength of joints formed by inter-filler (122.87 MPa) was significantly better as compared to those without using inter-filler (83.78 MPa). The optimum process parameters to achieve maximum tensile strength were found by CCD.

The strain‐based flex fatigue of 18 μm thick copper foil is evaluated over a wide range of strain amplitudes. Seven electrodeposited foils, four commercial grades and three experimental foils, and a commercial grade rolled foil are characterized. The fatigue life versus cyclic strain amplitude curve in the high strain amplitude (low cycle) and low strain amplitude (high cycle) regimes is developed for each foil. On the basis of fatigue life (N_f) and fatigue ductility (D_f), the low cycle fatigue performance of eight foils is ranked. Universal correlations of N_f and D_f with the uniaxial tensile strength are established. Two electrodeposited foils, experimental foil DF 8 in the high strain amplitude regime and commercial foil DF 9 in the low strain amplitude regime, have been shown to display fatigue performance comparable to that of the commercial rolled GR 8 foil.

This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties.

The surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM).

The experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used.

Previous laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

In the surface mount industry, microelectronic devices are reflow soldered to printed circuit boards with the benefit of mildly activated rosin (RMA) based fluxes. The residues from these fluxes, when not properly cleaned from the component boards, have been cited for decreased circuit life due to corrosion of the solder joints and loss of insulating resistance. Post‐solder cleaning operations with CFC (chlorofluorocarbon) solvents have been deemed environmentally harmful. Hence, there is a great need in the surface mount community for a no‐clean or fluxless solder reflow process. The BOC Group has developed a novel, proprietary process, by which circuit boards and their components are attached with a solder paste under a reactive fluxing atmosphere. The post‐solder residue is non‐corrosive and so minimal that it does not require a post‐solder cleaning operation. The solder joints exhibit good wetting, excellent joint strength and are essentially void‐free. Assembled circuits processed in this way meet all the criteria for ionic cleanliness and surface insulation resistance without post‐solder cleaning.

The purpose of this study is now to optimize the coil in a way that its lifetime is increased. In the industry, induction hardening of rotationally symmetrical workpieces in a single-shot process is a common method. Owing to only partial superimposition of the workpiece areas to be heated by the inductor, high power densities are frequently needed there. These lead to local hot spots, amounting to an intensive material stress in the copper and often result in short lifetime of the inductor.

In this elaboration, some numerically analysed approaches are presented that can be used to reduce mechanical stresses in the single-shot inductor and thus increase the service life.

It has been found out that changing the coil profiles has a strong influence on its lifetime. Besides that, the heat transfer coefficient between coil and coolant plays a big role and needs to be considered when the coil is dimensioned.

The lifetime of the coil is an important factor and often requested from the customers. Broken coils create a lot of extra costs and can generate downtime. Therefore, many customers that are struggling with thermal fatigue are interested in approaches that prolong the coil lifetime.

This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels.

For this purpose, immersion test and electrochemical polarization tests were conducted in mill and synthetic effluent to evaluate the uniform and localized corrosion.

Corrosivity of mill effluent has been compared with synthetic and primary-stage effluent of the same mill. It is observed that anions present in them, viz. SO₄−, PO₃4−, NO₂− and NO₃−, impart inhibition, whereas Cl− and chlorophenols enhance the corrosivity of the effluent. The overall effect of various components was reduction in corrosivity of secondary mill effluent.

These observations can be useful for material selection and helpful in corrosion mitigation in paper mill effluent treatment plants.

Processes for protecting copper surfaces during storage for solderability purposes were evaluated. The reason for the evaluation was to select the most cost effective method of achieving long‐term shelf life. A solderability test method was selected for the programme after reviewing various qualitative techniques such as Rotary Dip, IPC‐S‐801, MIL‐S‐202 Method 208, and the automatic quantitative Meniscograph instrument. A solderability test selection method was considered critical in the programme. Tests were conducted at 3 month intervals over a period of 1 year. From the data, a relative cost comparison showed air levelling to be more economical than organic sealers or hydrosqueeze. Air levelling has shown that circuit and plated‐through‐hole solderability can be maintained for a minimum of 1 year shelf life and is a practical process for both small and large production runs. When solder thickness was assured, test results also showed that both hand soldering and wave soldering could be performed on hard and flexible circuits without measling and pad lifting. The advantages of the process are presented in the paper so that the programme benefits can be applied to both present and future printed circuit board fabrication methods, including additive techniques. Manual soldering benefits of 300% improvement in wetting time and 90% faster wave soldering speeds were possible on air levelled surfaces. The levelling process covers both copper circuit sides of double and multilayer PCBs independent of circuit complexity and ground planes. This paper was originally presented at the First Printed Circuit World Convention held at the Cafe Royal, London in June, 1978.

The gas tungsten arc welding (GTAW) process is a widely used process that produces quality weldments. But the high heat generation from the GTAW arc can cause extreme temperatures as high as 20,000°C. The residual stresses and deformations are high accordingly. One of the methods for decreasing residual stresses and deformations is to change the welding pattern. In the literature, there are not so many examples of modeling dealing with welding patterns. This paper aims to investigate the influence of welding patterns on the deformations.

In this work, back-stepping patterns and partitioning of the weld line were investigated and the distortions and residual stresses were calculated. By doing this, temperature-dependent thermophysical and thermo-mechanical material properties were used. The temperature distribution and deformation from experiments with the same welding conditions were used for validation purposes.

Seven different welding patterns were analyzed. There is only one pattern with a single partition. There are three patterns investigated for both two and three partitioned weldings. The minimum deformation and the optimum residual stress combination is obtained for the last pattern, which is a three partitioned and diverging pattern.

The most important aspect of this paper is that it deals with welding patterns, which is not much studied beforehand. The other important thing is that the structural part and the thermal part of the simulation were coupled mutually and validated according to experiments.