General purpose covered electrodes
This type of covered electrode is the most common type of electrode where stainless steels are concerned. General purpose electrodes can be used for all types of stainless steels except high-alloy austenitic steels, which require clean welds to meet the demands for corrosion resistance and the prevention of hot cracking. Rutile electrodes should not be selected when high impact strength is needed at low temperature.
Sandvik Sanspray covered electrodes are of type -17 and are characterized by spray metal transfer with a smooth and stable arc. They are easy to strike and restrike, the amount of spatter is low and slag removal is easy. The weld bead is smooth with an even transition to the parent metal.
Special purpose covered electrodes
Rutile-basic covered electrodes
The rutile-basic electrodes, -16 type, have globular metal transfer. They are intended for fully austenitic parent metals with high molybdenum content, such as UNS N08028 and N08904. These electrodes are reliable in resisting hot cracking, give smooth and stable arc, easy stricking, low amount of spatter and easy slag removal.
Basic covered electrodes
The basic type (-15) has globular metal transfer. In comparison with the rutile-acid electrodes, the basic electrodes are harder to strike and restrike, and slag removal is not as easy. They give a slightly convex bead with deeper penetration than rutile electrodes. The main advantage of the basic electrodes is that they give cleaner weld deposits – less non-metallic inclusions and impurities. They are therefore recommended for parent metals of fully austenitic steels, such as type 25/22/2 and nickel alloys, in order to avoid problems with hot cracking. The basic type is also used in cryogenic applications which require good impact properties.
High deposition covered electrodes
These electrodes are of the rutile-acid -17 type. They are used when high productivity is required, but mainly in the flat position. Applications, for example, are large fillet welds and joints in heavy gauge plate, which cannot be performed with mechanized welding.
Covered electrodes for vertical welding
Special electrodes of the rutile-basic -16 type, which can be used for welding in the vertical down position. They can cope with large variations in gap widths and thin material. This has made these electrodes very suitable for maintenance work, especially within the pulp and paper industry.