AWS J1.3 Technical Specifications
| Property | Value | Unit |
|---|---|---|
| UNS Designation | C15000 | - |
| Composition | Cu + 0.10-0.20% Zr | % wt |
| Electrical Conductivity | ≥80 | % IACS (AWS J1.3) |
| Hardness | ≥65 | HRB |
| Thermal Conductivity | 365 | W/m·K |
| Softening Temperature | 525 | °C |
| Tensile Strength | 310-450 | MPa |
Recommended Applications
Galvanized Steels Zn, Galvanneal, Electrogalvanized
Coated Steels Al-Si (Usibor), Zn-Ni
Seam Welding Wheels for coated steels
Anti-Sticking Prevents zinc adhesion
The Zinc Problem and the Class 1 Solution
When welding galvanized steels, the zinc coating melts at ~420°C and tends to alloy with the copper of the electrode, forming brass (CuZn). This phenomenon causes:
- Sticking of the electrode to the workpiece
- Build-up of material on the electrode face
- Accelerated wear and loss of geometry
- Inconsistency in nugget quality
Class 2 (~75% IACS) → Higher zinc alloying
Class 1 (≥80% IACS) → Less alloying, dissipates heat faster
The high conductivity of Class 1 dissipates heat more rapidly, keeping the electrode face temperature below the alloying point of zinc with copper.
Tip Dressing: Although Class 1 reduces sticking, frequent tip dressing (every 200-500 welds) is recommended to maintain optimal geometry in galvanizing lines.