Butt welds
Full penetration butt welds are expected and their resistance is considered equal to that of the parent metal – Cl. 9.2.5.2.1.
Fillet welds
Fillet welds are designed by Simplified method according to Cl. 9.2.5.1.6.
- – vector sum of stresses in weld throat in all directions
- – design strength of fillet weld determined according to Table 9.2a and 9.2b; for cases not covered by Tables 9.2a and 9.2b:
- – for EN electrode used with EN steel
- – for other cases
- – minimum tensile strength of electrode
- – minimum tensile strength

The effective length of the fillet weld is reduced by according to Cl. 9.2.5.1.3, where is the fillet weld leg size assumed equal to .
| Electrode | |||
| Steel grade | 35 | 42 | 50 |
| S 275 | 220 | 220 | 220 |
| S 355 | 220 | 250 | 250 |
| S 460 | 220 | 250 | 280 |
| Steel grade | Electrode | Design strength |
| Q235 | E43 | 160 |
| Q345 | E50 | 200 |
| Q390, Q420 | E55 | 220 |
Tables 9.2a and 9.2b: Design strengths [MPa]
| Welding electrode | Minimum tensile strength [MPa] |
| 35 | 440 |
| 42 | 500 |
| 50 | 560 |
| E43 | 421.1 |
| E50 | 526.3 |
| E55 | 578.9 |
Default minimal tensile strength of electrode [MPa]
The weld diagrams show stress according to the following formula:
