Welded Connections

• Welding is the process of joining metal parts by fusing them & filling in with molten metal from the electrodes .
• Welding produces neat , strong  & more efficient joints than bolting .
• The weld quality depends very much on the skill of the worker . As such , careful supervision is required . This is possible in the fabrication yard .
• Site joints are usually bolted . Though site welding can be done , it is costly & defects are likely to occur .
• A good practice is to carry out shop welding & site bolting .
• Some welding test are :

- X - ray & ultrasonic test to check defects " inside ' the weld ( accurate ) .
- Dye penetration & magnetic particle test ( only on surface of weld ) .

There are 2 types of welded connections :

1. Butt weld
2. Fillet weld

Butt weld

• Butt welds are named after the edge preparation used . Examples are single & double U & V welds .
• BS 5950 requires the strength of the butt weld metal to be no less than the parent metal .
• Full penetration is ensured if weld from both sides or a backing plate is provided .

Fillet weld

• A fillet weld is the most common type of weld .
• The fillet weld is used to join two pieces of flat steel at a 90 degree angle .
• A fillet weld is produced by running a weld bead at a 45-degree angle to a 90-degree corner , it resembles a triangle when viewed from the side .
• The weld is used to fill the area where two pieces of steel meet , hence the name fillet weld .