Pure Tungsten Electrodes
Our pure tungsten electrodes exhibit superior characteristics at high temperature and deliver the exceptional performance required for resistance spot welding of non-ferrous metals. Our unique non-defective bonding (NDB) technology creates an electrode that provides the desired levels of thermal conductivity while reducing wear and increasing electrode life, resulting in maximum productivity and exceptional weld quality for your tungsten electrode applications.
Why Our Pure Tungsten Electrodes?
Welding a non-ferrous metal such as copper, which is used extensively in applications such as wire harnesses, motor windings, and electrical component manufacturing, is a challenge due to the material’s low electrical resistance and high thermal conductivity, which make it difficult to achieve the level of resistance heating necessary for welding. Therefore, welding of copper and other non-ferrous metals requires large electrical currents.
Designed and constructed based on our extensive expertise in tungsten, our high-performance pure tungsten electrodes are ideal for high-speed, automated welding applications that require such high levels of thermal and electrical conductivity, and superior hardness at high temperature. Using pure tungsten — with the highest melting point among metals, its excellent hardness at both room and high temperatures, and its resistance to forming an alloy with other metals — our electrode product provides a stable form and maintains current density during the welding process. Thanks to tungsten’s limited chemical reactivity with other metal components, there is low adhesion of the electrode with the workpiece.
Our pure tungsten electrodes have a tungsten weight ratio of 99.99% and higher, with a specific gravity of 19.2 and hardness of 450 HV. Based on the International Annealed Copper Standard (IACS), our pure product has an electrical conductivity of 31% and an electrical resistivity is 5.5 x10-8 Ωm.
Advantages of Our Unique NDB Process
Our pure tungsten electrodes not only produce the proper tip and shank profiles, but also take advantage of our NDB bonding method in electrode manufacturing. The unique NBD process produces a bonding area ratio of almost 100% and a bonding strength of ≥127 MPa. In comparison, tungsten electrodes that are brazed to their copper holders only achieve a bonding coverage area of as little as 60% to 80% maximum, and the bond strength of a brazed connection is only in the range of 98 MPa. Our high-quality NDB product results in pure tungsten electrodes that provide high heat conductance to the shank and superior cooling performance after the welding stops, as well as increased shot cycles and production efficiency.
For high-volume production, our NDB technology creates a welding electrode that delivers better thermal conductivity, lower electrical resistance, and lower electrical conductivity than copper to the junction. Unlike brazing and press fitting techniques for bonding an electrode to a shank, the NDB method provides superior levels of thermal conductivity while reducing wear and providing a stable bond that increases electrode life and the number or possible re-dressing processes. The enhanced cooling properties of our NDB pure tungsten electrodes counteract oxidation consumption, resist cracking, and improve surface textures.
You can read more about our NDB technology in our white paper, Better Together: Non-Defective Bonding of Resistance Spot Welding Electrodes.
Suited to a Wide Range of Automated Welding Applications
Our electrodes are used in large-volume automated resistance spot welding manufacturing environments. These same electrodes also work in die sinker applications.
For high-speed automated welding operations, our pure tungsten electrodes achieve the metal-to-metal surface contact and pressure needed for the very best weld possible. They are widely used for resistance spot welding in the automotive, electrical component, and home electronics industries, as well as for spot welding, copper wire fusing, and a wide range of other workplace materials. Some specific applications include automobile bodies and parts, wiring harnesses in electrical components of automobiles, line switches for battery packs, and electrical components for manufacturing lines of circuit breakers and electrical switches.
With low reactivity to most coated materials, our NDB pure tungsten electrodes are suitable for use with coated metal workpieces from metals such as galvanized or aluminized steel. Our NDB electrodes also exhibit a longer life for welding of chrome-free stainless steel, which can be problematic with conventional copper alloy electrodes. Our pure tungsten electrodes are also well suited to welding of tin-coated or nickel-coated copper workpieces, providing improved shot cycles and longer electrode life.