Because variables such as storage techniques, electrode diameter and flux composition all contribute to stick rod selection and performance, arming yourself with some basic knowledge can help you minimize confusion and better ensure stick welding success.
1. What are the most common stick electrodes?
Hundreds, if not thousands, of stick electrodes exist. 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. Each represents specific electrode properties.
For the mild steel electrodes mentioned above, here is how the AWS system works:
- The letter "E" indicates an electrode.
- The first two digits represent the resulting weld's minimum tensile strength, measured in pounds per square inch (psi). For example, the number 70 in a E7018 electrode indicates that the electrode will produce a weld bead with a minimum tensile strength of 70,000 psi.
- The third digit represents the welding position(s) for which you can use the electrode. For example, 1 means operators can use the electrode in all positions and 2 means welders can use it on flat and horizontal fillet welds only.
- The fourth digit represents the coating type and the type of welding current (AC, DC or both) that can be used with the stick electrode.
3. What are the differences between E6010, E6011, E6012 and E6013 electrodes and when should I use them?
- E6010 electrodes can only be used with direct current (DC) power sources. They deliver deep penetration and the ability to dig through rust, oil, paint and dirt. Many experienced pipe welders use these all-position electrodes for root welding passes on a pipe. However, E6010 electrodes feature an extremely tight arc, which can make them difficult for novice welders to use.
- E6011 stick electrodes can also be used for all-position welding using an alternating current (AC) welding power source. Like E6010 electrodes, E6011 electrodes produce a deep, penetrating arc that cuts through corroded or unclean metals. Many welders choose E6011 electrodes for maintenance and repair work when a DC power source is unavailable.
- E6012 electrodes work well in applications that require gap bridging between two joints. Many professional welders also choose E6012 electrodes for high-speed, high-current fillet welds in the horizontal position. However, these electrodes tend to produce a shallower penetration profile and dense slag that will require additional post-weld cleaning.
- E6013 electrodes produce a soft arc with minimal spatter, offer moderate penetration and have an easily-removable slag. You should only use these electrodes to weld clean, new sheet metal.
4. What are the differences between E7014, E7018 and E7024 electrodes and when should I use them?
- E7014 electrodes produce about the same joint penetration as E6012 electrodes and are designed for use on carbon and low-alloy steels. E7014 electrodes contain a higher amount of iron powder, which increases deposition rate. You can also use them at higher amperages than E6012 electrodes.
- E7018 electrodes contain a thick flux with high powder content and are one of the easiest electrodes to use. These electrodes produce a smooth, quiet arc with minimal spatter and medium arc penetration. Many welders use E7018 electrodes to weld thick metals such as structural steel. E7018 electrodes also produce strong welds with high impact properties (even in cold weather) and can be used on carbon steel, high-carbon, low-alloy or high-strength steel base metals.
- E7024 electrodes contain a high amount of iron powder that helps increase deposition rates. Many welders use E7024 electrodes for high-speed horizontal or flat fillet welds. These electrodes perform well on steel plate that is at least 1/4-inch thick. Welders can also use them on metals that measure over 1/2-inch thick.
5. How do I choose a stick electrode?
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 stick electrode type to the welding position and consider the available power source. Remember, you can use certain electrodes only with DC or AC, while you can use other electrodes 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 you use it 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 welding in the flat position, stick 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 stick 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, that dictates where and how an electrode can be used.
When you strike an arc, 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 I use a high deposition stick electrode?
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 you can't use high deposition electrodes in out-of-position applications.
You also cannot use them for critical or code-required applications, such as pressure vessel or boiler fabrication, where weld beads are subject to high stresses.
High deposition stick 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, you need to store many mild steel, low hydrogen E7018 electrodes 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.