A modern world would be unimaginable without electric arc welding - it is one of the oldest processes for joining metals and used all over the world. It is generally known as MMA (manual metal arc welding). Electric arc welding with stick electrodes is still indispensable in steel and pipeline construction and can be used under all weather conditions. Today, around 25 to 30% of the world's welded products are produced with this process.
Electric arc welding with stick electrodes is one of the oldest and most versatile welding processes. And it is also considered as one of the simplest and safest methods. It is used to weld almost all types of metals. Stick electrodes are even used for underwater welding.
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Process
For electric arc welding with stick electrodes, an electric arc is generated between the stick electrode and the base material. In shielded metal arc welding (SMAW) or manual metal arc welding (MMA) using coated stick electrodes, the coating forms a protective gas shield and a slag, thereby protecting the transferred metal droplets and the weld metal against contact with atmospheric oxygen.
Further functions of the coating are de-oxidation of the weld metal, increasing the metal recovery, compensating for burn-off and ensuring good wetting behaviour. In practical use there are three significant types of coating: rutile, basic and cellulosic and mixtures of these.
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