How To Distinguish ERW, LSAW, SSAW, And SMLS

-ERW (high frequency resistance welded pipe) : Hot rolled steel strip is used as raw material. After several processes, resistance heat is used in high frequency electric field to melt and crystallize the metal at the joint of the pipe to form a solid joint.
- LSAW (straight seam submerged arc welding pipe) : hot-rolled steel plate is used as raw material. After pre-bending and forming, double-sided submerged arc welding process is adopted. In the welding process, the weld is covered by a layer of granular flux to form a high-quality weld.
- SSAW (spiral seam submerged arc welding pipe) : The same as LSAW, the submerged arc welding process is adopted, but the steel strip is spirally advanced at a certain Angle during production and formed and welded to form a spiral weld.
- SMLS (Seamless steel pipe) : made by perforation, hot rolling, cold rolling or cold drawing process, the whole tube body without weld, is a single formed steel pipe.

- ERW: Usually suitable for small diameter pipes, the maximum diameter is generally not more than 660mm.
- LSAW: Suitable for large diameter pipes, usually between 406mm and 1500mm in diameter.
- SSAW: Larger diameter pipes can be produced, ranging from 406mm to 2540mm in diameter.
SMLS: A wide range of sizes, from small tubes less than 1/8 inch in diameter to tubes 24 inches in diameter and larger.

- ERW: has higher cost effectiveness, better dimensional accuracy and wall thickness uniformity, but lower strength and pressure resistance than SMLS.
- LSAW: With high strength and good toughness, plasticity and corrosion resistance, high dimensional accuracy, suitable for high pressure conveying.
- SSAW: Similar to LSAW performance, but because of the spiral weld, it can better disperse the stress when under pressure, and the same specification steel strip can produce a variety of diameter pipes.
- SMLS: high strength, excellent pressure and corrosion resistance, because there is no weld, the overall performance is more uniform, suitable for high pressure, high corrosion environment.

-ERW: Commonly used for water and gas transportation and structural purposes, such as urban gas and crude oil transportation.
- LSAW: It is mainly used for long-distance oil and gas transmission pipelines, especially in complex environments such as plateaus, undersea, and urban dense areas.
- SSAW: It is also used in oil and gas transportation, water transportation, mining and other fields, but it is limited by the form of weld, and the application is limited under certain specific requirements.
- SMLS: Widely used in petroleum, chemical, automotive, boiler, nuclear power and other industries with high requirements for pipeline strength, pressure and corrosion resistance.