BeginnerTopic 17 of 102Manufacturing, Robotics & Systems
Welding processes
MIG, TIG, arc and resistance welding join metals.
In depth
Arc (SMAW stick, MIG/GMAW, TIG/GTAW, SAW), resistance (spot, seam), oxyfuel, laser, electron beam and friction stir welding fuse parts. Weld quality depends on heat input, shielding, filler and joint design; defects: porosity, cracks, lack of fusion, distortion. HAZ properties and qualification standards (AWS D1.1) matter.
Key points
- Preheat and PWHT
- Weld symbols
- Welder certification
ExampleMIG welding with argon/CO₂ shielding is common for car and steel fabrication.
What is Welding processes?
MIG, TIG, arc and resistance welding join metals.
Why is it important to understand welding processes?
Welding joins metals permanently, so the process choice affects strength, cost, speed and the risk of distortion.
What is the difference between MIG and TIG welding?
MIG feeds a continuous wire and is fast, while TIG uses a non-consumable tungsten electrode and gives high control and quality for thin or critical welds.
How do I reduce distortion in welding?
Use a balanced welding sequence, control heat input, use fixtures and minimise the amount of weld metal.
How is Welding processes used in practice?
Typical applications include joining steel plates for a pressure vessel with submerged arc welding, using TIG welding for thin aluminium tubes in a bicycle and making spot welds on car body panels by resistance welding.
What should I learn before Welding processes?
Study "Sheet metal working" first (topic 16 of 102 in Manufacturing, Robotics & Systems). It covers the groundwork this topic builds on.
What are the key points of Welding processes?
Preheat and PWHT. Weld symbols. Welder certification.
Can you give an example of Welding processes?
MIG welding with argon/CO₂ shielding is common for car and steel fabrication.
What comes after Welding processes?
The next topic is "Soldering and brazing", which builds directly on this one.
How difficult is Welding processes?
It is classed as Beginner in Manufacturing, Robotics & Systems (topic 17 of 102). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.