Copper Development Association

Continuous casting of non-ferrous metals has been practised for well over 100 years. It has many advantages over static ingot and book mould casting, the most important being improved yield, reduced energy consumption and reduction of manpower, with a consequent reduction in cost. This book shows how the prrocess can be used in an engineering environment for casting a wide range of copper based alloys and precious metals, including gold and silver, and selected nickel alloys.

Cast and Wrought Aluminium Bronzes: Properties, Processes and Structure

Purpose: Purpose of this research is to study laser autogenous welding process of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1.0 [mm] thick. On the bases of results of quality assessment it was proved that high power diode laser (HPDL) welded lap joints of copper sheet provide mechanical properties on the level of parent material. Design/methodology/approach: Short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1,0 [mm] thick were tested, to establish the optimum parameters of high power diode laser autogenous welding process. Findings: It was shown that there is very narrow range of optimum HPDL autogenous welding parameters of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1,0 [mm] parameters. It was proved that high power diode laser (HPDL) autogenous welded lap joints provide mechanical properties on the level of parent material. Practical implications: It is possible to produce high quality short seam bead and fillet weld lap joints of oxygen-free copper sheets 1.0 [mm] thick. It was proved that high power diode laser (HPDL) autogenous welded lap joints provide mechanical properties on the level of parent material. Originality/value: The optimum HPDL autogenous welding parameters of short seam beads and fillet welds of lap joints of oxygen-free copper sheets 1.0 [mm] parameters makes possible to produce high quality laser autogenous welded lap joints of copper sheets 1.0 [mm] thick.

Study of laser welding of copper sheets

A new method of ceramic-ceramic and ceramic-metal joining has emerged over the past several years. Referred to as air brazing, the technique was originally designed and developed for use in fabricating high-temperature solid-state electrochemical devices such as planar SOFCs and oxygen and hydrogen concentrators. The primary advantage of air brazing is that a predominantly metallic joint can be formed directly in air without need of an inert cover gas or the use of surface reactive fluxes. The resulting bond is hermetic, offers excellent room temperature strength, and is inherently resistant to oxidation at high temperature. The key to developing a successful filler metal composition for air brazing is to identify a metal oxide wetting agent that is mutually soluble in a molten noble metal solvent. One particular oxide-metal combination that appears readily suited for this purpose is CuOx-Ag, a system originally of interest in the development of silver clad cuprate-based superconductors. Studies of the equilibrium phases studies in this system indicate that there are two invariant points in the pseudobinary CuOx-Ag phase diagram around which new braze compositions can be developed: 1) a monotectic reaction at 969±1°C, where CuO and a Ag-rich liquid L1 coexist with a second CuOx-rich liquidmore » phase L2 at a composition of xAg/(xAg + xCu) = 0.10±0.03 Ag and 2) a eutectic reaction at 942±1°C, where CuO and Ag coexist with L1 at a composition of xAg/(xAg + xCu) = 0.99±0.005. Specifically, near-eutectic Ag-CuO filler metal compositions have shown good promise in joining electrochemically active ceramics such as yttria-stabilized zirconia, lanthanum strontium manganite, and barium strontium cobalt ferrite, as well as alumina and magnesia. More recently it has been found that various ternary additions can further improve the wetting characteristics of these filler metals, increase their potential operating temperatures, and/or increase the resulting strength of the joint strength. Here we review the basic concept of air brazing and illustrate filler metal selection and design using the Ag-CuO system as an example.« less

Air Brazing: A New Method of Ceramic–Ceramic and Ceramic–Metal Joining

In this study, the effects of heat input variation in gas tungsten arc welding (GTAW), on structure and mechanical properties of commercially C86300 (containing addition of 0.6 wt% silicon) weld joint were investigated. Following microstructural characterization of Base metal, GTAW has been performed at welding currents 50 and 60 A and flow rates of argon shielding gas (10, 14 and 18 l/min) using the same filler metal composition. Therefore six GTAW samples were performed with various welding specifications. By structural investigations and hardness profiles, effects of increasing heat input on increasing average grain size in weld zone, heat affected zone width, penetration depth and alloying element losses were indicated. However increasing heat input increases penetration depth and has a positive effect on hardness and strength of the joint. In considering wear application of this alloy castings and probable GTAW for them, pin-on-disc wear test was performed and revealed better wear resistance of weld metal in comparison with base metal. Hence the optimum values of welding current and argon flow rates (in GTAW with the same composition filler) was determined for this alloy.

L. Brown

Papers

Joining of copper and copper alloys