An overview of welding technology, its applications, importance, and the different types of welding processes used in various industries.
Introduction to Welding Technology – Study Notes
| Term | Meaning |
|---|---|
| Base Metal | The workpiece(s) being joined. |
| Filler Metal (Electrode) | Consumable material added to the joint to fill the gap. |
| Heat‑Affected Zone (HAZ) | Area of the base metal whose microstructure changes due to welding heat, but which does not melt. |
| Weld Pool | Molten metal pool created during the welding operation. |
| Penetration | Depth that the weld metal extends into the base metal. |
| Joint Design | Geometry of the parts to be joined (e.g., butt, lap, fillet, corner). |
| Shielding | Gas or flux used to protect the molten weld from atmospheric contamination. |
| Process | Energy Source | Typical Applications | Advantages | Limitations |
|---|---|---|---|---|
| Shielded Metal Arc Welding (SMAW) | Manual electric arc | Construction, repair, pipelines | Simple, portable, inexpensive | Slower, limited to thicker sections |
| Gas Metal Arc Welding (GMAW / MIG) | Continuous wire feed + shielding gas | Automotive, fabrication | High deposition rate, easy automation | Sensitive to wind, requires gas supply |
| Gas Tungsten Arc Welding (GTAW / TIG) | Non‑consumable tungsten electrode + shielding gas | Aerospace, thin‑sheet, stainless steel | Precise control, clean welds | Slower, higher skill level |
| Flux‑Cored Arc Welding (FCAW) | Wire with flux core (with/without shielding gas) | Shipbuilding, heavy structural steel | High productivity, can be used outdoors (self‑shielded) | More smoke, heavier equipment |
| Submerged Arc Welding (SAW) | Arc beneath a blanket of granular flux | Long straight seams, pipe production | Very high deposition, deep penetration | Limited to flat/horizontal positions |
| Resistance Spot Welding (RSW) | Electrical resistance + pressure | Automotive body panels | Fast, repeatable, no filler metal | Limited to thin sheet metal |
| Laser & Electron Beam Welding | High‑energy laser or electron beam | High‑precision, aerospace, medical | Minimal HAZ, high speed, deep penetration | Expensive equipment, requires vacuum (EBW) |
| Friction Stir Welding (FSW) | Rotating tool generates frictional heat | Aluminum, aerospace, shipbuilding | Solid‑state (no melting), low distortion | Limited to compatible materials, tool wear |