Submerged Arc Welding (SAW — ISO 4063 Process 121) is a high-deposition-rate automated welding process in which the arc is hidden beneath a blanket of granular flux. Its high current capacity, deep penetration and excellent mechanical properties make it the preferred process for thick-section structural members, pressure vessels and bridge girders.
Because SAW minimises the human factor and welding parameters are precisely recorded, it integrates perfectly with the EN ISO 3834-2 quality system.
SAW Parameter Table
| Parameter | Typical Range | Effect |
|---|---|---|
| Welding Current (A) | 300–1200 A (DC or AC) | Directly affects penetration and deposition rate |
| Arc Voltage (V) | 26–42 V | Determines bead width and flux melting |
| Travel Speed (cm/min) | 30–120 cm/min | Affects heat input and bead geometry |
| Wire Diameter (mm) | 2.0–6.0 mm | Larger diameter = higher current capacity |
| Wire Feed Speed (m/min) | 0.5–3.0 m/min | Linked to current; determines deposition rate |
| Flux Type | Basic, acidic or neutral | Affects mechanical properties and slag characteristics |
Advantages and Limitations
Advantages:
- Very high deposition rate (5–20 kg/hr) — 3–5× that of MAG
- Deep penetration — single-pass thick section possible
- Since the arc is not exposed to open air, UV radiation and fume are minimal
- Excellent mechanical properties (especially with basic flux)
- Full automation compatibility
Limitations:
- Applicable only in flat (PA) and horizontal fillet (PB) positions
- Requires flux management — recycling and moisture control
- Not economical for short welds (long setup time)
- Risk of excessive penetration on thin plate (≤ 6 mm)
Application Areas
Structural applications where SAW excels:
- Pressure Vessels: Longitudinal and circumferential seams on cylindrical shells; 20–80 mm thickness range, single or double-sided
- Bridge Girders: Web-flange T-joint welds; high deposition and trace-free bead
- Heavy Machine Chassis: Thick plate butt welds
- Pipe Production: Spiral or longitudinal seam pipe manufacturing
Heat Input Note: Due to high current in SAW, heat input can be 3–8 kJ/mm. For high-strength steels (S690QL etc.) the maximum heat input must not be exceeded and must be explicitly stated in the WPS.
Submerged Arc Welding Capacity at ArmaWeld
ArmaWeld operates a 35 m submerged arc welding machine. Long linear seams, machinery and crane booms, and trailer and machine chassis are welded in one set-up in the PA and PB positions. Current, voltage and travel speed are recorded for every seam and checked against the WPS. More: submerged arc welding service · SAW for booms and chassis.
SAW Capacity for Your Heavy-Section Structures
Contact our technical team to evaluate your pressure vessel, girder or heavy construction project.
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