Manufacturing- Submerged Arc Weld

double-submerged-arc-weld

Double Submerged Arc Weld
Welding process wherein the required are usually accomplish in separate processes, hence the word ???double???. These separate welds consume a portion of the other, resulting in a single high quality weld nugget. DSAW pipe is normally produced in sizes from 24??? through 80??? OD. Pyramid rolls process the cylinder is formed between three rolls arranged in a pyramidal fashion.

DSAW pipe may or not may be cold expanded. Cold expansion is process where the pipe is an expanded dimension. In the process, a gain of yield strength results. Expansion is most often utilized in a U-O-E mill due to the need to recover the yield strength lost during the forming of in the ???0??? press. DSAW pipe is normally produced in double random lengths with square ends or beveled for welding. Fabrication services are available to produce lengths longer than the standard DRL (double random lengths 11-12 Mtrs). A wide range of external coating and internal linings are available with DSAW pipe.

Longitudinal Seam Submerged Arc Welded Pipes (LSAW)
With an installed capacity of 325,000 TPA in the facility, produces high quality pipes adhering to international standards. The manufacturing facilities incorporate the hybrid JCO&E technology, which provides flexibility in terms of thickness and grade, to produce pipes in a diameter range of 12 to 80, 6 mm to 65 mm thickness and grade up to API 5L X- 80. The facility also possesses latest inspection to meet specific requirements on execution, strength, tolerance, length etc.

Salient Features of LSAW Facility

  • Capacity to produce pipes with very close Diameter ??? Thickness ratio
  • Ultrasonic testing capable to scan 100% area of 5 meters wide plates to ensure internal soundness prior to pipe forming
  • LSAW Mill is equipped with 6000 MT JCO press, having capacity to form pipes of 65mm WT.
  • Cold expander (13 meters) to ensure tight and uniform control on pipe dimensions
  • Fully automated size and data controlled expander to ensure tight and uniform control and pipe dimensions.

Salient Features of HSAW Mill
The manufacturing process used for HSAW pipes consists of two steps:

  1. Pipe forming combined with continuous tack welding.
  2. Final internal and external submerged arc welding at separate welding stations.
  • The two step technology offers both quality and economic benefits such as:
  • High pipe forming speed by continuous tack welding
  • Emphasis on pipe geometry on pipe forming machine without hindrance by SAW process, resulting in tightest tolerance even without cold expansion with respect.
  • Straightness
  • Roundness
  • High quality due to implementation of process automation technology
  • HSAW forming mill has main drive feed motor with 500,000 Nm torque enabling pipe formation of 1 inch wall thickness comfortably.

API 5L PIPES
API 5L Line Pipe Testing Requirements

  • Hydrostatic Testing

Lists hydrostatic inspection test pressures for all sizes and graded covered by the specification.

  • Test pressures are held for not less than:

Seamless (all sizes) 5 seconds
Welded (NPS 18 and smaller) 5 seconds
(NPS 20 and larger) 10 seconds

  • Mechanical Test

Tensile Test

Seamless longitudinal
ERW longitudinal and transverse

  • Charpy Tests PSL-2
  • Flattening test ERW All sizes
  • Number of tests
  • Flattening Non-expanded ERW for single lengths, crop ends from each length; for multiple length; crop ends from first and last pipe of each coil, plus 2 immediate rings.
  • Tensile
NPS On One Length from each Lot
5 and smaller 400 or less
6 through 12 200 or less
14 and larger 100 or less

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  • Permissible Variations

Wall Thickness

?????????????????????? Seamless: 0.158-0.983 wall, tolerance = -12.5% / + 15%

?? ?? ?? ?? ?? ?? ?? ?? ?? ??> = 0.6984 wall, tolerance = -0.120 / +0.146 or – / + 10 % of whichever is greater (except if OD is > = 14 & wall is > = .984 then tolerance is -10 / +15%)

?? ?? ?? ?? ?? ?? ??HFW: < = 0.167 wall, tolerance = – / + .020

= 0.198-0.590 wall, tolerance = – / + .10.0%

= 0.591 wall, tolerance = – / + .060

Weights per foot

For Single Lengths Special Plain End and Grade A25 Not more than plus 10 % minus 5 %
For Single Lengths Other Pipe Not more than plus 10 % minus 3.5 %
For Carload lots not more than minus 1.75%

Note: NPS 2 OD and smaller may be weighed individually or in convenient lots; larger sized by length

Seamless Pipes

In the seamless pipe-making process tube rounds are heated in the furnace, after which they are pierced, then rolled by Mandrel or Plug-Mill process into pipes ??Read more

ERW Pipes

At the pipe mill the strip is uncoiled, levelled and crop-sheared. It is then trimmed on both sides simultaneously to correct width and immediately fed into the forming ????Read more

Spiral Weld Pipes

Spiral Weld as the name applies, is a steel pipe that has a seam running its entire length in a spiral form. In the past due to the method of manufacture, ??Read more

Submerged Arc Weld

Welding process wherein the required are usually accomplish in separate processes, hence the word ???double???. These separate welds consume a portion of the other ??Read more