The oil&gas field is one of the most served areas by Tecra together with the energy, chemical, petrochemical and naval fields.
The oil&gas industry is highly competitive and requires expertise, knowledge, quality and safety since it is a critical context where people often work in critical and severe contexts for applications requiring strict compliance with international legislation and standards.
In such circumstances, standard materials are not sufficient to satisfy these particular requirements, in fact, it is even necessary to identify other materials with better performance. In this regard, the best solution should be the so-called special materials such as Duplex, superduplex, Hastelloy, monel, Inconel and nickel alloys used for valves, piping, exchangers, offshore plants, processing lines and systems.
They are defined special because they have got an advanced chemical composition and high percentages of nickel, chrome, molybdenum or copper giving them specific characteristics compared to the standard materials.
Duplex and Superduplex offer a good balance between mechanical and corrosion resistance, especially in presence of chlorides and seawater.
It is easy to understand that superduplex guarantees better performance than duplex and in particular more pitting resistance and stress corrosion cracking.
In addition, monel alloys, that are nickel-copper based, offer an excellent resistance to seawater and marine environments.
The choice between Duplex/Superduplex and Monel mainly depends on the level of environmental aggressivity, on operational conditions and the cost-performance ratio.
In fact, the first ones are preferred in case
- chlorides corrosion
- and high mechanical resistance is required
In this case, especially considering Superduplex, they are used for piping offshore, subsea systems, desalinization plants, skid and manifolds and high pressure seawater lines. Furthermore, they provide better economies of scale for large-sized installations.
On the other hand, monel is preferred in marine environments characterized by:
- fluid high speed;
- erosion-corrosion risk;
- presenza di acido fluoridrico o ambienti chimici specifici;
- applications where an excellent resistance to stagnant or highly aerated seawater is required;
Furthermore, monel guarantees excellent performance against biofouling that is the unexpected and progressive accumulation of microorganisms, plants, seaweed and small animals on subsea surfaces that causes structural damages, corrosion etc.
That said, monel is surely more expensive, but it has got a lower mechanical resistance compared to superduplex.
It is generally chosen for more specific applications or in more aggressive chemical contexts when the presence of nickel-copper offer visible advantages.
On the other hand, Hastelloy alloys are particularly suggested for extreme chemical environments thanks to their outstanding resistance to corrosion and to aggressive acids.
Inconel and the other nickel alloys are used in contexts where high mechanical performance, resistance to stress and stability to high temperatures are required maintaining an excellent oxidation and corrosion resistance also in extreme operating conditions. For the fact that it is used in specific contexts, it is more expensive than duplex or superduplex.
Tecra is a specialized supplier of these materials. According to its company policy, it doesn’t stock them, but supplies them on demand to guarantee the maximum flexibility, a complete traceability and targeted supplies depending on the project needs.
Therefore, this choice is a real advantage for the customer since it reduces the risk of material obsolescence and, at the same, allows to optimize cost and time based on the actual application requirements.
Thanks to a qualified network of partners and international producers, Tecra can supply certified materials compliant with its customer technical specifications.