Products


HIC Plate

Oakley Steel sells fine grained pressure vessel steel resistant to Hydrogen Induced cracking (HIC) in the following grades ASTM/ASME A/SA 516 grades 60, 65 and 70.

HIC A 516 plate is available from stock in

     Thicknesses of 6 – 80mm,

     Widths of 2000 – 3500mm and

     Lengths of 3000mm to 12000mm.


Ex Stock HIC resistant plates are available from our Antwerp Warehouse for worldwide delivery

Problem:
HIC plate is mainly used in situations where the steel is exposed to a 'sour gas environment', particularly in the oil and gas industry. A sour gas environment is one with a high concentration of Hydrogen Sulphide H2S. Hydrogen ions are absorbed into the steel structure where they can combine into molecular hydrogen causing an effect similar to cracks induced by water freezing in rock. Micro-cracking often occurs under the surface of the steel making it difficult to detect through routine or non-intrusive maintenance, and cracks that are detected often cause long shutdowns whilst the damaged plate is replaced.

The benefits of using plate with improved HIC resistant are that safety risks can be reduced. Maintenance costs and plant down time can also be reduced. The benefits make HIC resistant plate a cost effective alternative to standard A 516 plates over the lifetime of the installation.

Production
HIC plate is meets all the requirements of the appropriate standard (ASTM A 516) but undergoes additional processing steps to give it is special qualities. Firstly the heats are vacuum degassed and hydrogen and nitrogen are removed during low level de-sulphurisation. This produces steel that is extremely 'clean' – it has very few remaining non-metallic inclusions – reducing the risk of hydrogen induced cracking. The steel is then continuously cast so as to ensure that any oxides remaining are not trapped on the solidification front but are able to rise and separate from the metal at the meniscus.

During rolling very high forces are applied to give very high per pass reduction rate leading to extremely high structural deformation even in the centre of heavy plates. This reduces and eliminates any remaining cavities. The steel is then normalised in an annealing furnace. The end result is steel that has a homogenous fine grained structure across the plate and which is much more effective at resisting hydrogen induced cracking.

Plate Details:
Certification EN10204 3.1

Tolerances to ASTM/ASME A/SA 20

Chemical Analysis:
As per standard and/or grade and in addition

Phosphorous (P) < 0.010%

Sulphur (S) < 0.0010%

Testing:
Immersion test to NACE TM 0284-03

Crack Evaluation to NACE TM 0248-03
•  Crack to Length Ratio (CLR) < 5
•  Crack Thickness Ration (CTR) < 1.5
•  Crack Sensitivity Ratio (CSR) < 0.5


Ultrasonic Testing to ASTM A 578 S2.2



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