Industeel®S420G2+Q: a weldable quenched and tempered steel for large offshore structures with excellent toughness and weldability

Industeel®S420G2+Q is a quenched and tempered structural steel plate grade with a nominal minimum yield strength of 380MPa* dedicated to large offshore structures in the North Sea and similar environments.
Option 18 of EN10225 can be qualified with a documentary file that has been reviewed by DNV-GL and Lloyd’s Register.
Its extreme purity with very low sulphur and phosphorus contents, as well as its adapted chemical analysis, makes Industeel®S420G2+Q easy to cut, shape and weld, and provides excellent impact toughness and CTOD properties in the very large sizes available.
Industeel®S420G2+Q is elaborated through Electric Arc Furnace (EAF) melting of selected scraps with fine grain practice, vacuum treatment and ingot casting to provide the necessary characteristics of the material.
The steel is rolled in plates with a quarto mill and finished using separate quenching and tempering heat treatments.

* 1MPa = 1N/mm²


EN10225:2009      S420G2+Q – plates (to 100 mm thickness per the standard, and above)

Industeel®S420G2+Q can be qualified to the following requirements of EN10225:2009

Option 12 (strain-ageing testing)
Option 13 (through-thickness testing)
Option 18 (Weldability testing)

This prequalification for Option 18 has been reviewed and approved by DNV-GL and Lloyd’s Register according to the file submitted for Industeel®S355G10+N thanks to the same range of chemistry.
The grade can be delivered according to NORSOK M-120 Ed. 5 datasheet MDS-Y30 Rev.5 and at thicknesses above the maximum defined in the standard.

Chemical analysis – weight %, maximum unless a range is indicated

C Si Mn P S Cr Mo Ni Al Cu
0.12 0.15


1.65 0.008 0.002 0.20 0.08 0.70 0.015




N Nb Ti V B Nb+V Nb+V+Ti CEV Pcm
0.010 0.030 0.025 0.060 0.0005 0.06 0.08 0.43 0.22

CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Cu+Ni)/15
Pcm = C + Si/30 + (Mn+Cu+Cr)/20 + Ni/60 + Mo/15 + V/10 + 5 B


Mechanical properties


Thickness range (mm) Yield Strength ReH (MPa) Tensile Strength Rm (MPa) Yield to tensile strengths ratio Elongation on base 5,65 √S0 A(%) Through thickness reduction of area Z (%)
80-200 Minimum 380 480-640 Minimum 0.85 Minimum 19 Minimum 35

Charpy Impact tests

Minimum values according to EN10225 Table 7

Test temperature Transverse direction impact test sub-surface Transverse direction impact test mid-thickness
-40°C Minimum 60 J Minimum 60 J



Download the complete datasheet

Technical data and information are to the best of our knowledge at the time of publication. However, they may be subjected to some slight variations due to our ongoing research programmes. Therefore, we suggest that information be verified at time of enquiry or order. Furthermore, in service, real conditions are specific for each application. The data presented here are for the purpose of description only, and can be considered as guarantees only when written formal approval has been provided by our company. Industeel reserves the right to change its product range at any time without prior notice.