SMAW / MMA Process (111) — Stick Welding Complete Guide
Introduction
SMAW (Shielded Metal Arc Welding), also known as MMA (Manual Metal Arc) or stick welding, process 111 per ISO 4063, is the oldest and most versatile welding process. It uses a consumable covered electrode that simultaneously provides filler metal, shielding gas and protective slag.
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Principle
The arc is struck between the coated electrode tip and the workpiece. The coating melts to produce shielding gas and slag that covers the weld during cooling. The core wire transfers to the weld pool as filler metal.
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Equipment
Simple and portable: power source (transformer, rectifier or inverter), electrode holder, earth clamp, cables and PPE.
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Parameters
| Parameter | Rule of thumb |
|---|---|
| Current (A) | ~30-40A per mm of electrode diameter |
| Polarity | DC+ for basic; AC or DC± for rutile |
| Arc length | ≈ core wire diameter |
| Electrode angle | 70-80° to workpiece, tilted in travel direction |
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Electrode Types
| Type | Key feature | Main use |
|---|---|---|
| Rutile | Easy to use, stable arc, good appearance | General fabrication |
| Basic | High mechanical quality, low H₂, must be baked | Structural, pressure, offshore |
| Cellulosic | Deep penetration, little slag | Pipeline vertical down |
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Advantages and Disadvantages
Advantages: Simple, cheap, portable equipment; works outdoors (wind-resistant); all positions; wide range of materials and thicknesses.
Disadvantages: Low productivity (~30% duty cycle), slag removal, manual skill required, electrode stub waste.
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Reference Manufacturers
Leading manufacturers of coated electrodes include Lincoln Electric (Omnia, Basique series), ESAB (OK series), voestalpine Böhler Welding (FOX series) and Eurotrod. For SMAW welding equipment, Fronius and Kemppi are also notable.
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*Article based on AWS Welding Handbook materials and ISO 4063. Published on WeldFC Academy.*