the welded steel pipes different advantages in ERW SSAW and LSAW

ERW steel pipe is short name of high frequency electric resistance welded pipe and made from raw material hot rolled steel plate by the continuous forming, bending, welding, heat treatment, sizing, straightening and cutting process. The advantages: compared with SSAW steel pipe, ERW pipe has high dimensional accuracy, uniform wall thickness, good surface quality, high pressure resistant performance etc. But ERW steel pipe can be only used in production of small diameter thin wall pipe, which is widely used in fields of gas and crude oil transportation in the city.

SSAW steel pipe is short name of spiral submerged arc welded pipe through rolling forming process and creating a forming angle in the rolling direction. After rolling process is welding process and the final pipe has a spiral welded seam. The advantages: SSAW steel pipe can be produced various diameters of steel pipes with the same specifications. The raw material range is wide. And the welded seam can avoid the principal stress to get good stress condition. While the disadvantage is poor geometry size and the welded seam length is longer than straight seam steel pipe. Welded defects such as cracks, porosity and slag occur occasionally. Welding stress is at tensile stress state. Oil and gas long distance pipeline is designed spiral submerged arc welded pipe but can be only used for 3, 4 class regions according to related rules and regulations.

LSAW welded pipe is for short straight seam submerged arc welded pipe. The production process is simple: using die or forming machine to roll steel plate into pipe shape, then double sided submerged arc welding. The advantages: the dimension range is wide. High toughness, good plasticity, good uniformity and compactness are important advantages. So in project construction of long distance oil and gas pipeline, LSAW welded pipe is important and required. On the basis of API 5L standard, it is the only designated welded steel pipe types in areas of cold area, sea and city populated areas.