The 7018 welding rod is a type of electrode used in the Shielded Metal Arc Welding (SMAW) process, commonly known as stick welding. Each part of the designation "7018" provides specific information about the properties and intended uses of the rod. Here’s a breakdown of what each number means:
70: The first two digits indicate the minimum tensile strength of the weld metal in thousands of pounds per square inch (psi). In this case, "70" means that the electrode will produce a weld with a minimum tensile strength of 70,000 psi.
1: The third digit indicates the position in which the electrode can be used. A "1" means that the electrode is suitable for all positions — flat, horizontal, vertical, and overhead. This versatility makes it a popular choice for various welding applications.
- 8: The last digit refers to the type of coating on the electrode and its intended use. The "8" indicates that the electrode has a low hydrogen content (the hydrogen level is controlled to be low), which reduces the likelihood of hydrogen-induced cracking in the weld. This characteristic is crucial when welding high-strength steels and in applications where integrity is critical.
Features and Benefits of 7018 Welding Rods
Low Hydrogen Content: The low hydrogen level helps prevent cracking and improves the toughness of the weld bead, making it suitable for structural applications.
Versatility: Suitable for all welding positions allows for flexibility in different projects.
Smooth Bead Appearance: Provides a clean, smooth weld bead that is aesthetically pleasing and likely to meet high-quality standards.
Good Penetration: The design of the electrode allows for good penetration into the base metal, making it useful for a variety of thicknesses.
- Applications: Commonly used for welding carbon steel and low-alloy steel in construction, shipbuilding, pipelines, and heavy machinery fabrication. It’s particularly favored in industries where structural integrity is paramount.
Usage Tips
Storage: Since 7018 rods are low-hydrogen electrodes, they should be stored properly to maintain their performance. They are often stored in a heated oven to keep moisture away.
Preheat: In some cases, especially when welding thicker sections or specific materials, preheating the base metal may be necessary to prevent cracking.
- Technique: Adopting the correct arc length and travel speed is crucial to achieving the best results when using 7018 rods.
In summary, 7018 welding rods are a reliable option for various welding applications, specifically where strength, ductility, and a low risk of hydrogen cracking are essential. Their versatility and performance make them one of the most commonly used electrodes in the welding industry.