Coating Types
It is the composition of the coating that differentiates one type of electrode from another, and to a degree, what type of application it can be used for. MMA electrodes, with a solid wire core, are generally categorised by the type of flux coating they employ. There are three main groups of electrode coating: rutile, basic, and cellulosic, plus a less-widely-used acid type. The name of each group is a description of the main constituent of the coating. Although not strictly a coating type, iron-powder electrodes are often considered as a separate group.
Electrodes for cutting, grooving and gouging, plus those for hard-surfacing, including tubular MMA electrodes, are not classified by coating type.
| Please select coating type: |
Rutile Electrodes
Rutile electrodes have a coating that contains about 50% rutile sand (a pure form of titanium dioxide), plus additions of ferro-manganese, mineral carbonates and silicates, held together with approximately 15% sodium silicate, also known as waterglass. The rutiles’ characteristics include easy striking, stable arc, low spatter, good bead profile and generally, easy slag removal from the electrode.
The electrode can operate on both AC and DC currents and can operate in all positions if the formulation of the coating is so designed.
One negative aspect of these electrodes is that they produce a high level of hydrogen, typically greater than 15ml/100g of deposited weld metal. This cannot be avoided because they rely on a certain amount of moisture being present in the coating to operate properly. If the electrodes are dried too much, they will fail to function properly.
Rutile-coated electrodes are manufactured for welding mild and low-carbon steels. In this context, they are often referred to as general-purpose or GP electrodes. Some low-alloy grades also use rutile coatings. Rutile-type coatings, which are modifications of those used for ferritic steels, are also used on some austenitic stainless steel electrodes.
Contact BOC
To order or for more information:
Phone us on | Email us at |
Visit us at | Or visit your local |
