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.
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.
Find here more information about the classification of stick electrodes.
More informationAccording to the European Norm DIN EN ISO 2560, there are a total of eight different types of coated stick electrodes for arc welding of unalloyed steels and fine-grained steel. The four main types are named after their main components:
*Acid electrodes can hardly be found anymore and have been almost completely replaced by rutile electrodes.
These coating types are a very important differentiator for the unalloyed stick electrodes. Stick electrodes for high strength, creep resistant or high-alloyed steels according to the other EN standards are mostly coated with rutile or basic coating elements.
Due to the high level of cellulose in the coating, they have excellent properties for out-of-position welding, but poor properties for horizontal welding. They are therefore mainly used for vertical-down welding on large pipes.
These electrodes are very popular due to their good welding properties. The welding arc is stable and calm and is easy to reignite, the seams are finely rippled, and most of the slag comes off by itself. Rutile-coated electrodes have sufficient toughness properties, but are only suitable for out-of-position welding to a limited extent (high-alloy). BÖHLER electrodes for under water welding are a special type namely rutile acid (RA). They have a special sealing to protect against the water.
The main advantages of basic electrodes are the outstanding toughness properties of the weld metal and its resistance to hot and cold cracks. Basic-coated electrodes have a coarse droplet material transfer, can be used to weld in all positions and have somewhat coarsely rippled seams. The slag can be relatively easily removed, but not as easily as with rutile-coated electrodes.
Each type of steel needs a different stick electrode. It can be differentiated between the following steel types:
Böhler Welding DRY SYSTEM is the efficient alternative for costly climate controlled storage and handling procedure, providing “oven dry” stick electrodes straight from the vacuum packaging. Böhler Welding DRY SYSTEM avoids the necessity of re-drying, and use of holding ovens and quivers in welding applications with a potential risk of hydrogen induced or hydrogen assisted cracking. Safe welding with low-hydrogen weld metal is assured up to nine hours after opening the vacuum pack.
Stick electrodes ensure easy and flexible handling without gases and simple power sources. Böhler Welding DRY SYSTEM vacuum packages together with user friendly packaging sizes offer optimal packaging content in industries where stick electrodes are of high priority.
Using a strong foil made of multi-layered aluminium, the new Böhler Welding DRY SYSTEM offers maximum safety against loss of vacuum due to the undesired penetration of sharp objects during storage and use. Welders will see immediately if the electrodes are still oven dry. With the vacuum in place, electrodes are ready to use. The packs can be stocked in any dry place where the packaging cannot get damaged. DRY SYSTEM is environmentally-friendly. No plastic in the form of PE or PP boxes is used at all.
Most welding consumables are classified in accordance with an EN ISO and AWS standard. There are a number of different EN ISO standards that apply for different areas:
AWS stands for American Welding Society. In relation to the fields of application and the alloying type the following classification exists:
Unalloyed electrodes AWS A5.1
E7018-1H4R
HIGH Alloyed electrodes AWS A5.4
E308L-16
Requirements: Good vertical-down welding properties
Answer: Cellulose electrode
Explanation: Due to its suitability for vertical-down welding (pos PG), this electrode type is used to weld circumferential seams on large diameter pipes (pipelines). Relatively thick electrodes (4 mm) can be used for root welding.
Requirements: Good bead appearance. Easy-to-remove slag and easy to reignite.
Answer: Rutile electrode
Explanation: The special properties of the electrodes are their good bead appearance, easy-to-remove slag and they are easy to reignite.
Requirements: Very high toughness properties
Answer: Basic electrode
Explanation: This electrode is suitable for all positions, and as a special type also for vertical-down positions. Basic electrode has the best toughness properties, even at low temperatures, and the highest resistance to cracking. It is used for difficult base materials and thick-walled parts. The low hydrogen content makes it possible to weld high-strength, fine-grained steels.
Requirements: Good vertical-up properties
Answer: Rutile basic electrode
Explanation: This electrode is good for welding on the root pass and in the vertical-up position in pipeline and container construction. It is also easy to handle in out-of-position welding.
Requirements: Good underwater properties
Answer: Rutile acid electrode
Explanation: For underwater welding, a stick electrode is needed with good seam quality to weld in wet environments in order to economically produce quality underwater welding connections.
