ERW vs LSAW vs SSAW Steel Pipe: Difference & How to choose

Welded steel pipe falls into two families by weld shape: straight seam (ERW, LSAW) and spiral seam (SSAW). ERW uses high-frequency resistance welding on coiled strip; LSAW uses submerged arc welding on single steel plates; SSAW also uses submerged arc welding but forms the weld in a spiral line. Each process gives the pipe a different diameter range, pressure rating, and ideal application. This guide gives you a quick side-by-side comparison — for a deeper dive into any single pairing, jump to our dedicated comparison pages linked below.

1. ERW vs LSAW vs SSAW: Quick Comparison Table

The table below summarizes how ERW, LSAW and SSAW differ across the factors that matter most when specifying pipe for a project — welding process, size range, pressure rating, cost and the standards each type typically meets. Use it as a quick reference, then check the sections and detailed guides below for the reasoning behind each figure.

	ERW	LSAW	SSAW
Full name	Electric Resistance Welded Pipe	Longitudinal Submerged Arc Welded Pipe	Spiral Submerged Arc Welded Pipe
Weld shape	Straight seam	Straight seam	Spiral seam
Welding process	High-frequency induction/contact welding	Double-sided submerged arc welding (UOE/JCOE/HME)	Submerged arc welding, spiral forming
Raw material	Hot-rolled steel coil	Single medium/thick steel plate	Steel coil
Typical diameter	Small–medium	Large	Small–large (flexible)
Typical wall thickness	Thin	Thick	Medium
Dimensional accuracy	High	High	Moderate
Pressure resistance	Medium–high	High	Low–medium
Cost	Low	Higher	Lowest
Typical use	Urban gas, oil/product transport, structural	Long-distance oil & gas trunk lines, offshore, high-pressure	Water pipelines, piling, low-pressure/non-critical lines
Common standard	API 5L, ASTM A53	API 5L PSL2, DNV	API 5L PSL1

2. Pipe Type Breakdown

ERW Steel Pipe

ERW (Electric Resistance Welded) pipe is made from hot-rolled steel coil through pre-bending, continuous forming, high-frequency welding, heat treatment, sizing and cutting. It offers short weld seams, high dimensional accuracy, uniform wall thickness and good surface finish. The limitation is that it's best suited to small and medium diameters with thinner walls. It's the standard choice for city gas networks and crude oil/refined product transport.

LSAW Steel Pipe

LSAW (Longitudinal Submerged Arc Welded) pipe is formed from a single steel plate, pressed into shape and welded on both sides using submerged arc welding, then expanded to final diameter. It delivers large diameters, thick walls, and strong performance under high pressure, high/low temperature and corrosive conditions. For long-distance oil and gas trunk lines — especially through alpine terrain, seabeds, or densely populated areas — LSAW is often the only pipe type that meets API requirements for Class 1/2 areas.

SSAW Steel Pipe

SSAW (Spiral Submerged Arc Welded) pipe is formed and welded simultaneously, with the weld seam running in a spiral line. A single strip width can produce multiple diameters, raw material use is more flexible, and the spiral weld can help distribute stress. The trade-off is lower dimensional precision and a longer total weld length, which increases the risk of porosity, slag inclusion and cracking. Most international codes restrict SSAW to Category 3/4 pipeline areas, though it remains widely used domestically for water transmission and lower-pressure lines.

3. How to Choose the Right Pipe Type

Need a large diameter, thick wall for high-pressure or long-distance oil/gas trunk lines → LSAW is the safer choice, and often the only compliant option for Class 1/2 pipeline areas.

Working with small-to-medium diameter, thinner-wall pipe for gas distribution or moderate-pressure service → ERW offers strong dimensional accuracy at a lower cost.
Prioritizing budget and need a wide range of diameters produced from the same coil → SSAW is the most economical, but limited to lower-pressure or non-critical applications (Class 3/4 areas).
Still unsure? Match your project's operating pressure, pipe diameter, and governing standard (e.g. API 5L PSL1 vs PSL2) against the comparison table above, or see the detailed pairwise comparisons below.

In-Depth Comparisons

Want the full technical breakdown between two specific types? See our dedicated comparisons: 
ERW vs LSAW Steel Pipe: Detailed Comparison — welding process, cost, and which one fits your pressure/diameter requirement 
LSAW vs SSAW Steel Pipe: Which Should You Choose? — operating pressure, budget, and dimensional accuracy compared

Where Can You Use Welded Steel Pipe? (ERW/LSAW/SSAW) — looking for pipe by application or standard instead of by process? See which national/industry standard applies to your project

4. FAQs

Q: Which is stronger, ERW or LSAW pipe?

A: LSAW generally offers higher pressure resistance and is preferred for high-strength, high-toughness long-distance pipelines. ERW performs well for small-to-medium diameter, thinner-wall applications at moderate pressure.

Q: Can SSAW pipe replace LSAW in oil and gas pipelines?

A: Only in lower-risk pipeline categories (Class 3/4 areas under most codes). Most countries — including the US, Japan and Germany — restrict or reject SSAW for high-pressure trunk lines where LSAW is required.

Q: Which type is the most cost-effective?

A: SSAW is typically the lowest-cost option due to continuous coil production and flexible raw material use, followed by ERW. LSAW carries a cost premium justified by its higher pressure rating and dimensional precision.