HIC Resistant Steel

MASTERHIC by Masteel UK Ltd.

Combatting the problem of hydrogen induced cracking in sour service, HIC steel plate is carbon steel plates which are tested to assess the susceptibility of the material to hydrogen induced cracking. This is a problem commonly found in wet H2S/sour service operating environments such as in the Oil, Gas and Petrochemical Industry.

MASTERHIC is Masteel UK Limited’s designation for HIC Steel for fine grain pressure vessels, offering specific and superior properties for sour gas application.

HIC resistant steel is manufactured via the electric arc furnace with desulphurisation, dephosphorisation, ladle refining and vacuum degassing to provide an ultra clean and homogeneous steel. HIC steel is particularly suited for pressure equipment where wet H2S corrosion can be a problem.

ASTM/ASME A/SA 516 60/65/70 in accordance with MASTERHIC 5/10/15 HIC Resistant Steel for Pressure Equipment in Sour Service.

HIC Resistant Steel is carbon steel which is tested to demonstrate the plate’s resilience to the long term effects of hydrogen induced cracking, tested according to NACE. Masteel UK Limited are pleased to offer HIC resistant steel plates from stock.

Below are technical details of our HIC resistant steel plate, including information relating to testing and identification…

MASTERHIC 5/10/15 is tested in accordance with NACE TM 0284-03 with test solution A (pH =3)

Testing / Documentation / Identification:

• Ultrasonic testing is performed in accordance with ASTM A578 level C.
• Impact tested at – 50 Deg C (Longitudinal)
• Supply Condition: Normalised
• Hardness tested according to NACE MR 0175 22HRC max
• Mill test certificates in accordance to EN10204 3.1, unless otherwise stated
• Marking on HIC plates is carried out according to ASTM/ASME A/SA 20

Thicknesses of 6mm to 100mm. Full profiling facilities are also available. Pre-allocated rolling schedules for HIC steel are available for project based contracts. Maximum HIC plate weight 15 tonnes.

Hydrogen Induced Cracking (HIC) occurs when carbon steel is exposed to hydrogen sulphide (H2S) and is the direct result of electrochemical corrosion reactions between the sour service or wet H2S environment.

Particularly common to the Oil and Gas Industry where the use of steel pressure vessels is widespread, the risks of this should be considered when hydrogen sulphide partial pressure becomes greater than 3.5mbar. Carbon steel pressure vessels should not be affected by HIC damage where H2S levels are lower than this figure in a normal service life cycle. HIC is prevalent in wet H2S environments, which is often known as sour service and such cracking over a prolonged period of time without inspection, will reach a critical point and the steel component, i.e. pressure vessel, could easily fail.

Simply put, hydrogen induced cracking damage increases as the level of hydrogen sulphide increases.

Steel Quality

Susceptibility to hydrogen blistering and hydrogen induced cracking can be apportioned to the quality of the steel plate used. Another type of hydrogen corrosion, Stress-Orientated Hydrogen Induced Cracking (SOHIC), is normally found in the base metal adjacent to the weld, where the stress point is highest due to the internal pressure of the vessel and the stress on the weld point itself. HIC & SOCHIC can also be found in steel pipework.

The onset of hydrogen sulphide corrosion poses a major problem for the oil and gas industry in particular – it is no coincidence that many facilities employ dedicated engineers who rigorously inspect pressure vessels for signs of wear and corrosion.

Masteel are experts in the supply of the highest quality HIC tested carbon steel plate for pressure vessels and boilers and have a stockholding at their UK distribution warehouse.

Stress-Oriented Hydrogen Induced Cracking or SOHIC is another hydrogen-induced cracking problem resulting from the same exposure to hydrogen sulphide (h2s) in wet h2s & sour service environments.

Differences between HIC & SOHIC

The pattern of cracking is somewhat different and tends to affect the stress load around the heat affected zone (HAZ) of welds since this is the weak point in the pressure vessel or pipe. SOHIC is most common where there is high hydrogen activity. SOHIC can also propagate from blistering caused by hydrogen induced cracking (HIC).

Once again, the supply of steel with resistance to stress orientated hydrogen induced cracking (SOHIC) is very important and while there are testing procedures available, a specific SOHIC susceptibility test has not been standardised to date.

At Masteel UK Limited, we can advise you on the particular type of HIC tested steel grade suitable for your needs and also advise on the types of testing required prior to processing and shipping. And with a variety of HIC tested steel in stock, we will happily accommodate all your pressure vessel and boiler steel plate requirements.

Essentially, the HIC test actually tests a sample of steel for its susceptibility to hydrogen embrittlement.

Hydrogen embrittlement involves the ingress of hydrogen into a component (e.g. pressure vessel, boiler) – a factor which can cause a variety of issues,  including cracking and reduction in load bearing capacity. This, in turn, can cause a catastrophic failure which represents a serious threat to any safe working environment.

Hydrogen can be introduced into steel during processing, in storage and in welding. It is also produced by corrosion reactions such as rusting. Hydrogen embrittlement is more susceptible in titanium and aluminium alloys and high strength steels. In a sour service environment hydrogen contamination is caused by the presence of hydrogen sulphide (h2s) which creates an electrochemically corrosive reaction.

To address the issues surrounding embrittlement, greater emphasis is being placed on steel at the processing stage. Alloys are developed with a higher resistance to hydrogen embrittlement and are HIC tested for hydrogen induced corrosion – all to the very highest testing standards. Controlling the amount of hydrogen that can potentially be picked up in the processing cycle and limiting the possibility for further hydrogen contamination on site, will prolong the life cycle of the component and limit the possibility of cracking and brittle failures.

Wet H2S Corrosion (hydrogen sulphide) is commonly found in the Oil Refinery and Gas Production Industries and is a deterioration process which can have a major impact, particularly in the use of pressure vessel steel plate. Since any damage takes place on the interior, detection can only be observed using complicated inspection methods.

As a consequence, a failure from such hydrogen induced cracking can occur without prior warning and represents a considerable hazard which in extreme cases can result in serious injury to operatives or even death.

Also known as ‘sour service’, issues including hydrogen blistering, hydrogen induced cracking (HIC) and stress orientated hydrogen induced cracking (SOHIC) are caused by the aqueous hydrogen charging of the steel. This charging can cause blistering and embrittlement, which is potentially disastrous in carbon steel pressure vessel environments. These conditions can be present wherever there is a wet H2s environment.

There are two primary attacks on carbon steel plate in a wet H2S corrosion scenario…

• Corrosion related
• Stress related

The levels of corrosion in steel plate in this scenario are dictated by numerous factors including the quality of the steel itself, the chemical composition of the material, and conditions, processing and treatments applied at the mill. The suitability of the steel plate for this purpose should be established from the test certificate at the completion of production.

The provision of HIC tested carbon steel plate is a major consideration for steel procurement in the oil and gas industry as it offers high resistance against the ongoing effects of hydrogen induced cracking (HIC).

Masteel supply HIC tested steel plate to global customers in the Oil ,Gas and Petrochemical Sectors. These customers demand the highest standards in terms of quality, durability and performance.

HIC tested steel plate is the ideal choice for pressure vessels and boilers in this particular market as it is tested for resistance against hydrogen induced cracking. It is deemed to be the most sensible and cost effective solution, since standard carbon steel plate is more prone to hydrogen sulphide corrosion in wet h2s and sour service environments, and is a far more cost effective alternative to stainless steel.

In essence, HIC testing is actually an evaluation of the steel for susceptibility to hydrogen embrittlement. The test procedure involves the evaluation of resistance of pressure vessel steel plate and pipework steels to hydrogen reduced cracking caused by hydrogen absorption from aqueous sulphide corrosion. An unstressed steel sample is exposed to a solution at ambient temperature and pressure. After a designated period, the sample is removed and assessed.

Our HIC tested steel plate is either tested at the mill or by an independent UKAS approved testing agency. However, as the steel we supply is generally for very high quality usage, our customers usually specify the test criteria themselves. Masteel can also help you formulate a test criteria for your pressure vessel steel. As far as is technically possible, your inspection and acceptance requirements can be tailored to your individual requirements.

Masteel UK Limited are able to supply fine grain pressure vessel quality HIC tested steel plates according to the Petrobras specification N–1706.

MASTERHIC which is Masteel’s own designation for HIC resistant steel is supplied according to ASTM /ASME A / SA 516 Grade 60, 65 & 70. Manufactured with desulphuristation, dephosphorisation, lade refining and vacuum degassing, the material is an ultra clean and homogenous steel which is particularly suited for pressure equipment in sour gas applications.

Features:

• Petrobras N-1706 Class A & B compliant
• Fully tested for susceptibility to hydrogen induced cracking (HIC)
• Meets specifications applied by the Oil, Gas & pressure vessel industry
• Supplied acccording to NACE MR0175 and MR0103
• Low carbon equivalent with excellent weldability
• Comprehensive stock range available