API 2W Grade 50 TMCP Offshore Steel Plates

Priming API 2W50 offshore steel plate

Priming API 2W50 offshore steel plate

Offshore steel plate to API 2W Grade 50 is kept in stock. Our plates are to a modified version of the API 2W-50 standard produced by Dillinger which provides improved performance

The API 2W grade 50 plates are all to 3.2 MTC and are produced by a G7 mill, Dillinger Hutte. The steel is made in Dillingen in Germany and then rolled in either Germany or France – depending on the thickness or the width.

Like all our offshore steels the API 2W-50 plates that we keep in stock are thermo-mechanically rolled which results in a lower alloy content, lower CEV and thus improved performance and a significant saving in weight.

API 2W Grade 50 plates have been used by many of our customers in Singapore, Malaysia and Indonesia when fabricating platforms, rigs, FPSOs and other offshore structures for the US market, or where a US company is the specifying company. Other clients prefer the range of offshore steels provided to EN10225 which we also stock (S355G10 + M), S355 G8 + M and S460G2 +M)

With API 2W-50 plate from Dillinger you get the normal exceptionally low sulphur and phosphorous content which significantly reduces imperfections in the steel and also the strength of the rolling stands which compressed the plate with a force of up to 11,000 tonnes given it an excellent microstructure.

Offshore plate to API 2W Grade 50 is stocked in thicknesses from 10mm to 100mm. Plate sizes are standard with 2m 2.5m and 3 m widths being available from stock. Standard API 2W50 plates lengths are 6m and 12m.

We keep an extensive stock of API 2W Grade  50 plates aiming always to ensure that our customers can meet all their requirements for offshore plate from our stock. This means large stock quantities and a focus on the thicker plates, up to 100 mm, so that all requirements can be met from our own stock.

For customers requiring API 2W Grade 6o steel plates we will generally offer S420G2+M. For the API 2H grade 50 plates we will offer S355G7/8/9/10+N plates

Other offshore grades available include S355G10+MS355G8+MS420G2+MS460G2+M and S460ML

API 2W Grades Available Ex-Stock

GradeGrade AvailableMax Thickness
API 2W Grade 50API 2W-50100 mm
API 2W Grade 60S420G2+M or S460G2+M100 mm

API Specification 2W

API spec 2W is the API’s spec “Steel Plates for Offshore Structures, Produced by Thermo-Mechanical Control Processing (TMCP)”. It covers two grades of plate – Grade 50 and grade 60 (the strength is in KSi so grade 50 has an MPa of 344 and grade 60 414 MPa). The plates are designed for use in critical potions of offshore structures which have to resist impact, plastic fatigue loading and lamellar tearing.  API 2W grade 50 steel is at least equivalent in minimum performance to API spec 2H steel grades. The higher performance of API 2W50 is then delivered through the impact of the TMCP rolling.

The main use for API 2W Grade 50 plates is in tubular joints, stiffened plate construction and other locations where parts of the plates will be subject to tension in the through thickness or Z direction (which is why so many of out plates are sold with Z35 testing.).

API 2W plate is often preferred to API 2H or API 2Y steel grades as the lower carbon content (see below for CEV and Pcm values) means improved weldability and thus lower production costs. Dillingers superior metallurgical control generally means that we are able to supply API 2W 50 plates that have some of the lowest carbon content available improving your production still further. Additionally after welding there is good toughness in the HAZ (Heat Affected Zone) which makes production easier and improves the performance of the structure being built.

Because of the TMCP production process API 2W 50 plates will generally be fabricated by either cold forming or welding. Hot forming is likely to reduce or remove many of the benefits associated with TMCP and is unlikely to be replicable by on site processing.

API 2W Chemical Composition – Heat Analysis

ElementAPI 2W Grade 50API 2W Grade 60
C0.16
Mn1.15 to 1.6
P0.03
S0.010
Si0.05 to 0.50
Ni0.751.0
Cr0.250.25
Mo0.080.15
Cu0.35
Ti0.007 to 0.020.007 - 0.002
Nb0.03
B0.0005
Al0.02 to 0.06

API 2W specification Carbon Equivalent Values – CEV and Pcm

 ThicknessAPI 2W 50API 2W 60
Max Thickness150 mm100 mm
CEV≤40 mm0.390.42
> 40 mm to ≤ 90 mm0.41
> 40 mm to ≤ 100 mm0.45
> 90 mm to ≤ 150 mm0.43
Pcm≤40 mm0.220.25
> 40 mm to ≤ 90 mm0.23
> 40 mm to ≤ 100 mm
> 90 mm to ≤ 150 mm0.240.45

API 2W Physical Properties

Property API 2W-50API 2W-60
Yield Strength (MPa)t ≤ 25 mm345 - 517414 - 621
t > 25 mm345 - 483414 - 586
Tensile Strength (MPa)448517
Elongation in 50 mm min %2322
Elongation in 200 mm min %1816

API 2W Grade 50 Equivalent Grades

Based on the yield strength and general properties API 2W Grade 50 can often be replaced EN10225 S355G10+M, and API 2W60 by EN10225 S420G2+M. Whilst not directly equivalnt a review by engineers and the QA department has often found that the EN10225 offshore steels can be used in place of API 2W spec steels. Similarly API 2H steels can often be replaced with the EN 10225 normalised steels – i.e. S355G10+N and S355G8+N.

API 2W Supplementary Requirements

  • S1 – Ultrasonic examination
  • S2 – Notch toughness testing at lower temperature
  • S3 – additional Tension test
  • S4 – Through thickness Z Testing
  • S5 – Low Sulphur steel for improved through thickness (Z) properties
  • S 7 – Low nitrogen content for improved notch toughness in strain aged condition
  • S8 –  strain aged Charpy V-Notch impact tests
  • S9 – Simulated post weld heat treatment – PWHT
  • S10 – Hardness Testing
  • S11 Preproduction qualification
  • S12 Notch toughness using Drop weight
  • S13 Surface quality
  • S14 – Thickness tolerance

You can purchase API Spec 2W (R2012) from the API