Stick electrodes

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. 

Coating types

According 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:

• C (Cellulose) cellulose electrodes
• A (Acid) acid electrodes*
• R (Rutile) rutile electrodes
• B (Basic) basic electrodes

*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.

Cellulose-coated stick electrodes

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.

Rutile-coated stick electrodes

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.

Basic-coated stick electrodes

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.

Stick electrode portfolio

Each type of steel needs a different stick electrode. It can be differentiated between the following steel types:

• Stick electrodes for unalloyed steels
• Stick electrodes for high-strength steels
• Stick electrodes for creep resistant steels
• Stick electrodes for stainless steels
• Stick electrodes for nickel and nickel alloys

DRY SYSTEM

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.

Optimal quantity for high demanding industries

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.

DRY SYSTEM user benefits

• Guarantee of low-hydrogen weld metal - an important prerequisite in the prevention of hydrogen cracks
• Avoidance of costly climate controlled storage and handling and re-drying. Simple distribution to welders
• Possibility to check whether electrodes are within 9 hours of safe exposure
• Content can be chosen to match fabricator or industry specific consumption
• Can be disposed with normal paper and metal waste

Classification

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 Standard

AWS stands for American Welding Society. In relation to the fields of application and the alloying type the following classification exists:

• AWS A5.1/A5.1M Specification for carbon steel electrodes for shielded metal arc welding
• AWS A5.5/A5.5M Specification for low-alloy steel electrodes for shielded metal arc welding
• AWS A5.4/A5.4M Specification for stainless steel electrodes for shielded metal arc welding
• AWS A5.11/A5.11M Specification for nickel and nickel-alloy welding electrodes for shielded metal arc welding