Welding methods in AMU context: gas, arc, TIG, MIG and MAG
An overview of the methods and their applications
Introduction
AMU courses in welding cover multiple methods because different tasks require different techniques. Understanding the strengths and limitations of methods is part of being a versatile welder.
Every process has a number
Welders, drawings and welding procedures (WPS) use a number instead of a name. The number comes from the standard ISO 4063. The current edition is the 5th edition from 2023. The table shows the numbers you will most often meet on an AMU course.
| Method | No. | What the number covers |
|---|---|---|
| Covered electrode (MMA, «stick») | 111 | Manual arc welding with coated electrode |
| MIG | 131 | MIG welding with solid wire |
| MAG | 135 | MAG welding with solid wire |
| MAG with cored wire | 136 | MAG welding with flux-cored wire |
| MAG with metal-cored wire | 138 | MAG welding with metal-cored wire |
| TIG with filler | 141 | TIG welding with solid filler wire |
| TIG without filler | 142 | TIG welding without filler material |
| Gas welding | 311 | Gas welding with oxygen and acetylene |
Gas welding (311)
Gas welding uses a flame from fuel gas and oxygen. It provides good heat control and is used for thinner materials, heating and certain repairs. The method requires no power source and is therefore flexible in the field.
Manual metal arc welding with covered electrode (111)
Manual arc welding with coated electrode (MMA) is robust and works well outdoors because the coating itself forms protection over the weld pool. It is used a lot for construction and repair work and requires only a power source and electrodes.
TIG (141 and 142)
TIG uses a non-consumable tungsten electrode and a separate filler rod. The method produces very clean and controlled welds and is used where there are high demands on quality and appearance — e.g. on stainless steel and thinner materials.
MIG and MAG (131, 135, 136 and 138)
MIG and MAG are wire welding processes with high productivity. MIG uses inert shielding gas (typically for aluminium and stainless steel), while MAG uses active shielding gas (typically for unalloyed and low-alloyed steel). They are well-suited for batch and production work.
| Method | Typical application |
|---|---|
| Gas | Thin materials, heating, repair |
| Manual arc (MMA) | Construction and repair, outdoors |
| TIG | High quality stainless thin material |
| MIG/MAG | Production, both thin and thicker goods |
Fumes, ozone and gas — the processes differ
The processes do not produce the same air pollution. BFA Industri's guide to welding describes them like this:
| Process | Røg | Ozone |
|---|---|---|
| Manual metal arc welding (111) | Considerable | Not formed |
| MAG with solid wire (135) | Considerable | Increases with the current and can be heavy |
| MIG welding (131) | Considerable | Large amounts, especially with aluminium-silicon alloys |
| TIG (141 and 142) | Almost no visible fumes, but ultrafine particles | Considerable amounts |
At high current, the ozone forms in a sphere up to one metre around the arc. Then the low-pressure extraction cannot capture all the ozone. MAG with cored wire produces the same kind of pollution as MAG with solid wire, but more carbon monoxide.
Example: the processes in the blacksmith programme
The blacksmith training regulations (in force from 1 August 2026) have the subject Energiteknik 3 (energy technology 3). Here the apprentice must weld according to ISO 9606-1 in these processes and positions:
- 01111 in low-alloy and non-alloy steel: PB, PA, PC, PH and H-L045
- 02131 in AlMg alloys (aluminium with magnesium): PB, PD and PF
- 03135 in low-alloy and non-alloy steel: PB, PA, PC, PH and H-L045
- 04136 and 138 in low-alloy and non-alloy steel: PB and PA
- 05141 in low-alloy and non-alloy steel and in stainless materials: PB, PA, PC, PH and H-L045
- 06142 in thin-walled stainless materials: PA, PC, PH and PJ
The welds must be made to quality level B (the regulations say «level B according to EN 5817»). The letters PA to PJ are welding positions. They are explained in the article on joint types and welding positions.
Versatility as a welder
The skilled welder masters multiple methods and can choose the right one for the task. The AMU system makes it possible to build up competencies step by step and certify yourself in the methods you work with.