Low hydrogen electrodes are stick welding or Shielded Metal Arc Welding (SMAW) consumables with a low amount of hydrogen in their covering. Generally they contain less than 0.6% coating moisture whereas conventional cellulosic electrode coatings have 4-6% moisture. Low hydrogen electrodes are qualified only when they don’t have more than 0.6% moisture content at 1800°F (980°C) as per the American Welding Society (AWS) carbon steel electrode test specification.
While moisture is necessary for forming and extruding in the welding process, an excess amount of it can cause brittle failures, delayed cracking or hydrogen-induced cracking. Low hydrogen SMAW electrodes also have good penetration and deposition rates. That’s why they are commonly used in welding thick metal sections, bridge and building construction, restrained joints, power generation, and high pressure-high temperature service steels.
The AWS E7018 is the most popular electrode in this category.
How should Low Hydrogen Electrodes be stored?
If low-hydrogen electrodes are exposed to room air for a prolonged period, the coatings may absorb hydrogen from condensation. In such a scenario, it will no longer be classified as low hydrogen. Hence, when it comes to storing stick electrodes, the best practice is to store them in an airtight box or hermetically sealed container at a temperature above the dew point.
A few other guidelines for storing stick electrodes are:
If stored in a heated room in a cold place, the temperature should be above 15°C.
If stored in a hot and humid environment with relative humidity below 50%, the temperature should be ambient.
It is highly advisable to avoid storing the electrodes at a temperature more than 25°C.
Follow the First In First Out (FIFO) method to take out the electrodes for the operational purposes.
What is Low Hydrogen Baking Procedure?
However, the general practice is to dry them before every use. You can consider re-drying, breaking or reconditioning them to restore the right moisture content. Rebaking is possible, albeit under strict supervision and with precise accuracy. The electrodes can be baked for 1-2 hours at 500°F-800°F. However, it is advisable to follow AWS or manufacturer guidelines for baking the electrodes.
If you are looking for high quality low hydrogen medium and high tensile steel electrodes, you can get them from D&H Sécheron. Some of our low hydrogen electrode products include Cromotherme-1, Supratherme and Ultratherme. Visit www.dnhsecheron.com to know more.