Welding

Welding

1. TIG (Tungsten Inert Gas)

   • Arc formed between piece and tungsten tip, non-consumable electrode, filler rod added separately by operator, weld is shielded by argon gas
     • ADVANTAGES: very precise, high quality, used to weld aluminium and stainless steel

2. Oxy-Acetylene welding

   • oxygen and acetylene mixed together to create flame, three types of flame: Oxidising (more oxygen than acetylene), Carburising (more acetylene), Neutral ( equal parts).
     • Acetylene would explode if put under pressure, so it si stored in a porous material called acetone, which can hold 25 times its own volume. This is called dissolved acetylene.
     • oxygen stored in black tank and acetylene stored in maroon tank. the hoses are also colour coded, oxygen hose threaded to only fit oxygen tank and vice versa, flashback resistors prevent flame travelling back up through hose.

3. MIG (Metal Inert Gas)

   • Heat source is electric arc between work piece and wire, Semi-automatic process with consumable electrode, feed and flow rate set by operator, inert gas creates protective shield around weld pool
     • ADVANTAGES: doesnt produce slag, long welds without starts and stops, minimal skill required, allows welding in all positions, used for low and medium carbon steels, used in robotic welding, car manufacturing, tubular frames

4. Submerged-Arc

   • Fully automatic, consumable electrode produces weld pool which is automatically fully covered by flux from hopper to prevent oxidation
     • Suitable for long run welds