Resistance Welding Products
Copper Alloys find its very common application in resistance welding equipment and tools.
Selecting the right copper alloy for resistance welding equipment particularly for gun arms, Projection welding electrodes, Seam welding wheels and Spot welding electrodes and caps is dependent on large number of design criteria and most often it is a trade-off between strength and electrical conductivity.
Copper Chromium and Copper Chromium Zirconium alloys have good thermal conductivity but tend to soften at lower temperatures thereby by significantly reducing the quality of weld and life of electrode. Copper Beryllium (RWMA Class 3 and 4) alloys are used high weld force or high weld currents are required. However these alloys are expensive for commercial applications and therefore are ususally substituted with less expensive materials.
Automotive Industry faces major challenges as electrodes have to be continuous replaced adding to downtime, cost and loss in productivity.
Alloys for Resistance Welding
QTi alloys offer advantages for resistance welding application where it provides relatively good electrical conductivity and high strength and affordable costs.In applications of High current or weld force QTi alloys provide performance. The table below compares the properties of QTi alloys with Copper Beryllium alloys for welding applications.
|RWMA Class||Composition||RWMA Alloys||Hardness (BHN)||Electrical Conductivity (% I.A.C.S)||Tensile Strength MPa||Elongation %||Mode||Annealing beginning at C|
|Class 4||Copper Beryllium||4.1720||353||23||1,172||4||Wrought||375 C|
|Copper Titanium||400||20||1200||3||Wrought||450 C|
Copper Titanium has a clear advantage in terms of strength and hardness over other alloys being used in resistance welding tools.
- It is observed CuCr/CuCrZr is used for Gun arms/shanks as a lesser expensive alternative to Copper Beryllium. But it comes with an added or disadvantage advantage of reduced strength and hardness.
- Here, Copper Titanium becomes a perfect replacement for CuBe, as it is equally as strong as CuBe and less expensive.
Gun arms/shanks were strength is a key criteria. % I.A.C.S is not important.
- Copper Titanium Gun arms can be of smaller diameter as compared to CuCr/CuCrZr providing cost effectiveness.
- Copper Titanium has a higher annealing temperature, it provides advantage for welding thicker or dis-similar materials.