Stick welding requires skill
Whether you are a DIYer who stick welds only a few times a year or a professional welder who welds every day, one thing is certain: Stick welding requires a lot of skill. It also requires some know-how about stick electrodes (also called welding rods).
Because variables such as storage techniques, electrode diameter and flux composition all contribute to stick electrode 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, but the most popular are mild steel electrodes, which fall into the American Welding Society (AWS) classification A5.1. These include the 6010, 6011, 6012, 6013, 7014, 7024 and 7018 electrodes.
|6010 electrodes deliver deep penetration and have the ability to “dig” through rust, oil, paint or dirt, making them popular among pipe welders.
2. What do AWS stick electrode classifications mean?
To help identify stick electrodes, the AWS uses a standardized coding system. Codes take the form of numbers and letters printed on the side of each stick electrode, and 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 the electrode can be used. For example, 1 means the electrode can be used in all positions and 2 means it can be used 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 electrode.
7018 electrodes produce strong welds with high impact properties and can be used on high strength steel base metals.
3. What are the differences between 6010, 6011, 6012 and 6013 electrodes and when should they be used?
- 6010 electrodes can only be used with direct current (DC) power sources. They deliver deep penetration and have 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, 6010 electrodes feature an extremely tight arc, which can make them difficult for novice welders to use.
- 6011 electrodes can also be used for all-position welding using an alternating current (AC) welding power source. Like 6010 electrodes, 6011 electrodes produce a deep, penetrating arc that cuts through corroded or unclean metals. Many welders choose 6011 electrodes for maintenance and repair work when a DC power source is unavailable.
- 6012 electrodes work well in applications that require gap bridging between two joints. Many professional welders also choose 6012 electrodes for high-speed, high-current fillet welds in the horizontal position, but these electrodes tend to produce a shallower penetration profile and dense slag that will require additional post-weld cleaning.
- 6013 electrodes produce a soft arc with minimal spatter, offer moderate penetration and have an easily-removable slag. These electrodes should only be used to weld clean, new sheet metal.
4. What are the differences between 7014, 7018 and 7024 electrodes and when should they be used?
- 7014 electrodes produce about the same joint penetration as 6012 electrodes and are designed for use on carbon and low-alloy steels. 7014 electrodes contain a higher amount of iron powder, which increases deposition rate. They can also be used at higher amperages than 6012 electrodes.
- 7018 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 7018 electrodes to weld thick metals such as structural steel. 7018 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.
- 7024 electrodes contain a high amount of iron powder that helps increase deposition rates. Many welders use 7024 electrodes for high-speed horizontal or flat fillet welds. These electrodes perform well on steel plate that is at least 1/4-inch thick. They can also be used 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 base metal strength properties and composition. For example, when working on mild steel, generally any E60 or E70 electrode will work.
Next, match the electrode type to your welding position and consider your 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.
You will also want to assess the joint design and fit-up you need and select an electrode that will provide the best penetration characteristics (digging, medium or light). If you are 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.
You should also consider the production efficiency. When working in the flat position, electrodes with a high iron powder content, such as such 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 wire 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 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 have the ability to 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 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, however, 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 7018 electrodes need to be stored at a temperature between 250 and 300 degrees Fahrenheit.
Generally, electrodes' reconditioning temperatures are higher than the storage temperature, to help eliminate excess moisture. To recondition the low hydrogen 7018 electrodes discussed above, the reconditioning environment ranges from 500 to 800 degrees for one to two hours.
Some electrodes, like 6011s, 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.
For specific storage and reconditioning times and temperatures, always refer to the manufacturer's recommendations.