Hundreds, if not thousands, of stick electrodes exist, but the most popular fall into the American Welding Society (AWS) A5.1 Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding. These include the E6010, E6011, E6012, E6013, E7014, E7024 and E7018 electrodes.2. What do AWS stick electrode classifications mean?
To help identify stick electrodes, the AWS uses a standardized classification system. Classifications take the form of numbers and letters printed on the sides of stick electrodes, and each represents specific electrode properties.
For the mild steel electrodes mentioned above, here is how the AWS system works:
First, select a stick electrode that matches the strength properties and composition of the base metal. For example, when working on mild steel, generally any E60 or E70 electrode will work.
Next, match the electrode type to the welding position and consider the available power source. Remember, certain electrodes can only be used with DC or AC, while other electrodes can be used with both DC and AC.
Assess the joint design and fit-up and select an electrode that will provide the best penetration characteristics (digging, medium or light). When working on a joint with tight fit-up or one that is not beveled, electrodes such as E6010 or E6011 will provide digging arcs to ensure sufficient penetration. For thin materials or joints with wide root openings, select an electrode with a light or soft arc such as an E6013.
To avoid weld cracking on thick, heavy material and/or complicated joint designs, select an electrode with maximum ductility. Also consider the service condition the component will encounter and the specifications it must meet. Will it be used in a low temperature, high temperature or shock-loading environment? For these applications, a low hydrogen E7018 electrode works well.
Also consider the production efficiency. When working in the flat position, electrodes with a high iron powder content, such as E7014 or E7024, offer higher deposition rates.
For critical applications, always check the welding specification and procedures for the electrode type.6. What function does the flux surrounding a stick electrode serve?
All stick electrodes consist of a rod surrounded by a coating called flux, which serves several important purposes. It is actually the flux, or the covering, on the electrode that dictates where and how an electrode can be used.
When an arc is struck, the flux burns and produces a series of complex chemical reactions. As the flux ingredients burn in the welding arc, they release shielding gas to protect the molten weld pool from atmospheric impurities. When the weld pool cools, the flux forms slag to protect the weld metal from oxidation and prevent porosity in the weld bead.
Flux also contains ionizing elements that make the arc more stable (especially when welding with an AC power source), along with alloys that give the weld its ductility and tensile strength.
Some electrodes use flux with a higher concentration of iron powder to help increase deposition rates, while others contain added deoxidizers that act as cleaning agents and can penetrate corroded or dirty workpieces or mill scale.7. When should a high deposition stick electrode be used?
High deposition rate electrodes can help complete a job faster, but these electrodes have limitations. The additional iron powder in these electrodes makes the weld pool much more fluid, meaning that high deposition electrodes can't be used in out-of-position applications.
They also cannot be used for critical or code-required applications, such as pressure vessel or boiler fabrication, where weld beads are subject to high stresses.
High deposition electrodes are an excellent choice for non-critical applications, such as welding a simple liquid storage tank or two pieces of non-structural metal together.8. What is the proper way to store and re-dry stick electrodes?
A heated, low humidity environment is the best storage environment for stick electrodes. For example, many mild steel, low hydrogen E7018 electrodes need to be stored at a temperature between 250- and 300-degrees Fahrenheit.
Generally, reconditioning temperatures for electrodes are higher than the storage temperature, which helps eliminate excess moisture. To recondition the low hydrogen E7018 electrodes discussed above, the reconditioning environment ranges from 500 to 800 degrees F for one to two hours.
Some electrodes, like E6011, only need to be stored dry at room temperature, which is defined as humidity levels not exceeding 70 percent at a temperature between 40 and 120 degrees F.
For specific storage and reconditioning times and temperatures, always refer to the manufacturer's recommendations.