Different types of welded steel pipes: ERW VS SSAW

ERW (resistance welded steel pipe) and SSAW (spiral welded steel pipe) are two common types of welded steel pipe. The main difference between them is the manufacturing process and the application scenario, and here is a comparison of the two:

1. ERW (Resistance welded Steel pipe)

Manufacturing process: ERW steel pipe is heated by high frequency current, both sides of the steel strip are heated to close to the melting point, and the two sides of the steel strip are welded together by resistance heat. It is then cooled to form a steel pipe.

Welding method: Adopt linear welding, that is, butt welding at both ends, and the weld is in a straight line.

Appearance characteristics: ERW steel pipe appearance is relatively straight, weld on the surface of the pipe is straight, more neat.

Application: Suitable for small diameter pipeline, widely used in structure, oil and gas transportation and other industries, especially suitable for low pressure pipeline.

Pipe specifications: Usually used for the production of smaller caliber (generally 2" to 24") steel pipes.


2. SSAW (Spiral welded steel pipe)

Manufacturing process: The SSAW steel pipe is to spiral the steel strip together at a certain Angle, and then weld the two ends of the steel strip together through arc welding to form a spiral weld.

Welding method: The use of spiral welding, that is, the two ends of the steel strip according to a certain Angle to form a spiral, the weld is spiral.

Appearance characteristics: The weld of SSAW steel pipe is spiral, usually the welding line is long, and the surface has obvious spiral marks.

Application field: Due to the characteristics of spiral welding, SSAW steel pipe is suitable for large diameter pipelines, widely used in oil, natural gas transportation, large water pipelines and other fields.

Pipe specifications: Usually used to produce large caliber (generally 24" to 120") steel pipes.

The main differences are:

Features	ERW steel pipe	SSAW steel pipe
Welding mode	Straight welding	Spiral welding
Pipe specifications	minor-caliber	large-caliber
Weld appearance	Straight weld	Spiral weld
Scope of application	Low pressure transport, structural tube	High-pressure transport, large diameter pipeline
Manufacturing cost	Lower cost	Higher cost
Pipeline performance	Suitable for low pressure environment	Suitable for large caliber, high pressure environment

Frequently Asked Questions

1. What is the main difference between ERW and SSAW steel pipe?

The main difference is the welding process and weld seam configuration. ERW pipe uses electrical resistance welding to create a straight longitudinal seam, while SSAW pipe uses submerged arc welding to create a spiral seam. ERW is commonly used for small- to medium-diameter products, whereas SSAW is often selected for large-diameter pipe projects.

2. Is ERW steel pipe stronger than SSAW steel pipe?

Not necessarily. Strength depends on the steel grade, chemical composition, mechanical properties, wall thickness, manufacturing quality, and applicable product requirements. The welding process alone is insufficient to determine which pipe is stronger. Buyers should compare certified material properties and the relevant test results for the specific products.

3. Is SSAW steel pipe suitable for high-pressure pipelines?

SSAW pipe can be used in qualifying pressure-pipeline applications when the applicable standard and project design permit it and the pipe meets all required material, dimensional, weld-quality, and testing criteria. Its suitability must be evaluated for the specific service; SSAW should not automatically be classified as either a high-pressure or low-pressure product.

4. Which is more economical, ERW or SSAW steel pipe?

ERW is often economical for standard small- and medium-diameter pipe produced in volume, while SSAW can be cost-effective for large-diameter pipe. However, the final price depends on the outside diameter, wall thickness, steel grade, order quantity, inspection scope, coating, and delivery requirements.

Conclusion

ERW and SSAW steel pipes serve different manufacturing and project requirements. ERW is often a practical choice for standard small- and medium-diameter products, while SSAW offers flexibility for large-diameter applications.