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Structural Hollow Sections

UOE Double Submerged Arc Welded (DSAW) SHS

LIBERTY Steel Hartlepool 42” DSAW mill employs the well proven UOE method of pipe manufacture featuring the world’s strongest crimp and O-press combination.
Our UOE DSAW mill process ensures tubular properties which meet the requirements of a wide number of grades of EN 10219 (Cold Formed Structural Hollow Sections).
Following double submerged arc welding, the tubular is mechanically expanded and can be produced in a wide range of sizes. We are one of the few manufacturers operating today capable of forming as low as 16 inch (406.4mm) and up to 42 inch (1066.8mm) outside diameter DSAW pipe.

With the option to source plate either from LIBERTY Steel’s own plate mills or from other quality suppliers, LIBERTY Pipes 42” Mill is able to provide the best technical solution to meet customers’ bespoke project or stock requirements. This highest quality feedstock and the achievement of extremely tight tolerances to aid circumferential welding contribute to the outstanding performance of our end product.

Weld seam ultrasonic testing used modern, phased array techniques and x-ray radiography (prior to expansion and post-expansion) are among a battery of tests incorporated in the process to ensure the integrity of the tubular.

Click here to download the full Structural Hollow Sections brochure.

Properties and performance

  • Consistent size and shape control in excess of the requirements of EN 10219 and EN 10210
  • Excellent weld toughness (with MLH and NLH grades available).
  • High quality surface condition
  • High integrity weld non-destructive inspection, with capability far in excess of EN 10219/10210


  • Extensive choice of outside diameter and wall thickness combinations
  • Thick wall tubular able to be welded in a single pass per side
  • Fast size changes within industrial scale production to meet project demands, allowing smaller quantities to be considered when compared with typical offerings within the industry
  • Option for profiling/saddle cutting of tubular ends using 6-axis profile burning machine
  • Tight length range control (exact lengths)
  • Girth welding for extended lengths
  • Available roofed space with OHCs for ancillary sub-contracting work to be carried out
  • Hot finished tubulars to EN 10210 are available using either on-site furnacing or sub-contracted locally

Approvals & Accreditations

The 42” Mill has a full suite of approvals and accreditations by independent third parties necessary to supply material into the oil and gas sector:


Area Approvals
Quality Management System ISO 9001, ISO 29001
Welding Control Systems ISO 3834-2
Health and Safety Management System OHSAS 18001
Environmental Management System ISO 14001
Product Licenses EN 1090-2

42” SAW Mill grades and sizes

Wall Thickness (mm) Diameter (mm)
406.4 457.2 508 558.8 609.6 660.4 711.2 762 812.8 863.6 914.4 965.2 1016 1066.8


Up to S460 strength (equivalent to X65) Strength levels from S355 to S460
  • Available grades: S275J0H, S275J2H, S355J0H, S355J2H, S355K2H, S275NH, S275NLH, S355NH, S355NLH, S275MH, S275MLH, S355MH, S355MLH, S420MH, S420MLH, S460MH, S460MLH.
  • Piece weight restricted to 12tonnes; please note that some sizes are based on < 12.2m mean length. If piece weight exceeds 12tonnes, small quantities may be possible – please check with mill.
  • Some capabilities are based on < 12m nominal lengths due to pressing force required; at peripheries of capability (within 3mm) always check direct with mill.
  • All forming is cold, with subsequent mechanical expansion. EN 10210 material is available through on-site heat treatment or heat treated by an approved sub-contractor.
  • Feedstock condition is N, NR or TM.
  • Maximum length is 12.8m; Minimum length is typically 10.0m, but down to 9.25m is occasionally available dependent on specification. Greater lengths are available via girth welding/jointing facility.
Can we help? Castings production tradition dates back to 1951. Long term experience in castings production is currently used for production of demanding grey iron and nodular iron castings for metallurgical and engineering companies in the Czech Republic and abroad. The operation unit includes also a pattern shop and scales treatment center. The unit obtained product certificates from Bureau Veritas for the entire product range and Lloyd's Register for grey iron and nodular iron castings with a piece weight up to 15 000 kg.

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