What is ERW steel pipe and SAW steel pipe

ERW steel pipe

ERW steel pipe is a kind of resistance welded steel pipe, high frequency resistance welding (Electric Resistance Welding, abbreviation

For ERW) ERW is the corresponding English word first letter. Resistance welded steel pipe is divided into AC welded steel pipe and DC welded steel pipe twoforms.

AC welding in accordance with the frequency is divided into low frequency welding, intermediate frequency welding, ultra-IF welding and high frequency welding. High-frequency welding is mainly used for thin-walled steel pipe.

Or ordinary wall thickness of the production, high frequency welding is divided into contact welding and induction welding.

DC welding is generally used for small diameter steel pipe.

Therefore, in general, high-frequency welded pipe is included in the ERW pipe, is a high-frequency welding process to produce an ERW pipe. ERW Longitudinal Welded Pipes (ERW) are the most advanced and economical steel pipes in the field of oil and gas storage and transportation.

SAW steel pipe

SAW steel pipe SAW full name Submerged Arc Welding Steel Pipe It is a submerged arc welding process using steel pipe, the process produces a very high current density, the flux layer to prevent the rapid loss of heat, and its focus on Welding area. Submerged arc welding is widely used in the manufacture of pressure vessels, pipe fittings, beam and column, low pressure fluid, steel structure engineering, with high quality, high production efficiency, no arc and dust.

SAW steel pipe main products are LSAW steel pipe Longitudinally Submerged Arc Welding Steel Pipe straight seam double-sided submerged arc welded steel pipe, which is the use of submerged arc welding technology to produce straight seam steel pipe.

Advantages of LSAW steel pipe

In the long-distance pipeline construction, with steel lines account for a large proportion, under normal circumstances, 35% to 40% of line pipe investments accounted for total project investment.

How to choose a reasonable price, excellent performance of the pipe is particularly important, a reasonable choice to save the pipe construction investment, to facilitate the construction and safe operation of the pipeline system has a very important impact. LSAW steel pipe advantage make it can be widely used for its unique long-distance oil and gas pipelines.

Advantages of LSAW steel pipe are:

  1. without the unwind process, the base material indentation, scratch less.
  2. the wrong side, slotted, and other easy-to-diameter perimeter control, excellent welding quality.
  3. the elimination of flaring basically does not exist residual stress after stress.
  4. because it is a straight line weld, the weld is short, little risk of defects.
  5. after expanding, pipe geometry accuracy is improved greatly facilitate the on-site welding.
  6. for a straight seam, less impact on the quality of anti-corrosion coating materials.

(This article comes from Sunny Steel Enterprise editor released)

Difference between SSAW steel pipe and LSAW steel pipe

Metallurgical properties of raw materials

Straight seam submerged arc welding tube is made of steel, but spiral submerged arc welding steel pipe production is usd hot rolled steel coil strip. The hot strip rolling process with a series of advantages, has a metallurgical process for production of high-quality line pipe capacity.

Welding process

From the welding process, spiral steel pipe welding method is the same as lsaw steel pipe, but the straight seam submerged arc welding tube inevitably will be a lot of T-weld, so the probability of presence of welding defects also greatly improved, and T-welds welding residual stress weld metal are often in a three dimensional stress state, increasing the possibility of cracks.

According to the submerged arc welding process requirements, each weld should have the arc at the extinction,but each steel pipe is unable to meet the conditions in welding girth,which may be at the extinction more welding defects.

(This article comes from Sunny Steel Enterprise editor released)

LSAW Steel Pipe

The use of LSAW:

LSAW steel pipe has large diameter and wall thickness, resistance to high pressure, resistance to low temperature and strong corrosion characteristics. When constructing high strength and toughness, high quality oil and gas pipeline over long distances,what is required is mostly large caliber straight double submerged arc welding joints. According to the API standard provisions, LSAW is the only designated for tube type when passing through the cold region, submarine, the urban population dense area of 2 kinds, 1 region in the large oil and gas pipeline.

(This article comes from carbon-pipe.com editor released)