Welding Rod Selection by Seamless Steel Pipe Material

There is no single welding rod for all seamless steel pipe (SMLS Pipe). The right choice depends on the pipe material and grade, the welding process, wall thickness, welding position, service temperature and medium, and the welding procedure specification (WPS) for the project. For carbon steel seamless pipe, E6010 and E7018 are commonly used in some applications, while low alloy and stainless steel pipe need electrodes that match their chemistry.

This guide covers rod selection only. In shielded metal arc welding (SMAW), the coated welding rod is also called a stick electrode, and this guide uses “welding rod” and “welding electrode” interchangeably. GTAW and GMAW use bare filler wire or rods with separate classifications, so check the WPS if the project uses those processes.

Welding Rod Selection by Seamless Steel Pipe Material

1. Welding Rod for Carbon Steel Seamless Pipe: E6010 and E7018

When stick welding is used, carbon steel seamless pipe is welded with covered electrodes classified under AWS A5.1. E6010 and E7018 are two of the best-known welding rod types for carbon steel pipe, but they do different jobs.

Neither is a universal choice for seamless steel pipe. Both are carbon steel electrodes under AWS A5.1 and should be used where the WPS calls for them. Some projects specify other electrodes or processes for the root pass, and thicker or higher-strength pipe may call for different consumables.

2. Low Alloy Steel Seamless Pipe

When stick welding is used, low alloy pipe, such as chromium-molybdenum steel used in high-temperature service, is welded with low alloy electrodes classified under AWS A5.5. In E8018-B2, the first two digits (80) indicate the minimum tensile strength class in ksi, and the suffix indicates the weld metal alloy. E8018-B2 and E9018-B3 are chromium-molybdenum types with nominal 1¼Cr-½Mo and 2¼Cr-1Mo deposits. These are low-hydrogen electrodes, and preheat, interpass temperature and post-weld heat treatment are set by the WPS and the applicable code. Carbon steel electrodes such as E7018 are not a substitute for alloy-matched electrodes.

3. Stainless Steel Seamless Pipe

When stick welding is used, austenitic stainless steel seamless pipe is welded with stainless electrodes classified under AWS A5.4, and the filler is normally chosen to match the pipe grade. E308L is commonly used for 304 and 304L, and E316L for 316 and 316L. The “L” indicates low carbon, which reduces the risk of sensitization. Duplex and other grades need their own matched fillers per the WPS. For joining stainless steel to carbon steel, E309L is commonly used because of its higher chromium and nickel content. Carbon steel electrodes such as E6010 and E7018 are not suitable filler for stainless pipe.

Read a full guide: What Welding Rod is Used for Seamless Steel Pipe? 

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