What Welding Rod is Used for Seamless Steel Pipe?

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 for Seamless Steel Pipe: Quick Selection Guide

Pipe material	Common electrode classifications	AWS specification	Selection note
Carbon steel seamless pipe	E6010, E7018	A5.1	The role of each electrode and the final choice depend on grade, wall thickness and the WPS
Low alloy steel seamless pipe	Alloy-matched types, e.g. E8018-B2, E9018-B3 for Cr-Mo steels	A5.5	The classification suffix indicates the weld metal alloy; match it to the pipe chemistry
Stainless steel seamless pipe	E308L, E316L, E309L (austenitic grades)	A5.4	Match the filler to the pipe grade; E309L is commonly used for stainless-to-carbon steel joints

These are examples, not a grade-to-electrode chart. Final selection follows the WPS, the applicable code and the electrode manufacturer’s data sheet.

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.

Item	E6010	E7018
AWS specification	A5.1	A5.1
Coating	High cellulose sodium	Low-hydrogen, iron powder
Minimum tensile strength class	60 ksi	70 ksi
Welding current	DCEP	AC or DCEP
Typical application on a pipe	Root passes where deep penetration is needed	Fill and cap passes where low hydrogen is needed
Main limitation	Not a low-hydrogen electrode; rougher bead	Moisture-sensitive; generally not chosen for open-root passes

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.

How to Choose a Welding Rod for Seamless Steel Pipe

Factor	What to check
Base metal grade	Confirm the pipe material, grade and chemistry on the mill test certificate, then select the electrode type (A5.1, A5.5 or A5.4) for that material
Strength matching	Weld metal strength is normally selected to meet the base metal strength requirement in the WPS; a higher strength class is not automatically better
Wall thickness	Thicker walls generally mean more weld passes and closer hydrogen control; thick sections often call for low-hydrogen electrodes with preheat and interpass control per the WPS
Welding position	The electrode must be suitable for the positions in the WPS; electrode diameter is chosen for the wall thickness and position
Service temperature	Low-temperature service may require impact-tested electrodes (some classifications carry a suffix such as -1 for lower-temperature impact properties); high-temperature service may call for alloy-matched chromium-molybdenum electrodes
Medium and environment	Corrosive media may require filler metal that maintains the corrosion resistance of the pipe, as with stainless steel; the project specification may add further limits
WPS, PQR and code	The qualified WPS and procedure qualification record are the final authority; changing the electrode classification may require a new or revised qualification under the applicable code

Welding Rod Storage and Handling

1. Keep welding rods in their original packaging in a dry place until use, and keep them dry on site.

2. Storage and drying needs differ by electrode type. Low-hydrogen electrodes such as E7018 absorb moisture and are usually kept in heated holding ovens or rebaked as the manufacturer instructs; cellulosic electrodes such as E6010 are handled differently. Do not apply one drying temperature or time to all electrodes. Follow the manufacturer’s data sheet and the WPS. 

3. Do not use electrodes with peeling or cracked coatings, or with oil or other contamination on the rod.

4. Tack welds should use the same electrode type as the production weld, unless the WPS states otherwise.

FAQs

Q1: What do the numbers in E6010 and E7018 mean?

A: Under AWS A5.1, the first two digits give the minimum tensile strength in ksi (60 and 70). The third digit shows the welding position (1 means all positions), and the last two digits together indicate the coating type and welding current.

Q2: Is E6010 or E7018 better for seamless steel pipe?

A: Neither is better in general. E6010 is a cellulosic electrode with deep penetration, commonly used for root passes. E7018 is a low-hydrogen electrode, commonly used for fill and cap passes. Which one applies, and where, is set by the WPS.

Q3: Can E7018 be used for all seamless steel pipe?

A: No. E7018 is an AWS A5.1 carbon steel electrode. Low alloy and stainless pipe need electrodes matched to their chemistry, and wall thickness, service temperature and the WPS also affect the choice.

Q4: Do seamless pipes need a different welding electrode from welded pipes?

A: Generally no. Electrode choice follows the base metal grade, strength requirement, wall thickness and the WPS, so the same selection logic applies to seamless and welded pipe of the same material.

Related articles: Seamless Steel Pipe Welding Methods and Techniques