Use of CRA materials in the Oil & Gas industry
CRA is an acronym that stands for Corrosion Resistant Alloys.
Have we reached Peak Oil?
For many years, analysts and energy experts have been announcing the arrival of Peak Oil, the point when the extraction of and demand for hydrocarbons will reach its maximum level and then begin to fall, being in all probability replaced by renewable resources.
Nevertheless, the reality today is that those who predicted a Peak Oil 15 years ago were wrong: Oil and gas reserves have continued to be our main source of energy for the last few decades. This has caused the available conventional reserves to be depleted, which has forced the exploration of areas where access and extraction are more difficult.
The offshore sector has grown significantly in recent times and is expected to continue to do so over the coming years, while ultra-deepwater extraction is gaining prominence. The use of CRA materials is fundamental in this industry, where extraction and production have become a great challenge compared to the methods used with conventional reserves.
Advantages of corrosion-resistant CRA materials
- They can withstand higher temperatures and pressures
- They are less acidic and less corrosion-prone
All this has forced the Oil & Gas industry to develop new technologies and new materials that guarantee the profitable, and especially, the safe production of oil and gas.
For this purpose, the use of corrosion-resistant steels and alloys (CRA) has become widespread. These alloys have become indispensable in order to meet ever-more demanding requirements in exploration and production: the demand for special alloy steels, stainless steels and nickel alloys for upstream oil and gas applications has grown substantially and this trend is expected to continue.
Which CRA to choose?
Selection of corrosion resistant steels and alloys
CRAs can be characterized and classified according to their ability to withstand specific environments where their corrosion-related properties are a key factor.
Among them, the most common are the stainless steels (304/304L, 316/316L), duplex and superduplex (22Cr, 25Cr …), and also nickel alloys (625, 825, C-276 …) among others. What makes them different is that they all contain chromium, nickel and molybdenum (the latter to a lesser extent), accompanied by other elements in smaller quantities that make each of them unique, with special characteristics that make it stand out from the rest.
Interesting facts about CRA materials
316L stainless steel exhibits good corrosion resistance in chloride-free environments, so it is used in acid gas handling facilities that are chloride-ion-free.
Duplex steels show better anti-corrosion properties than the above when working at higher temperatures.
Super duplex steels have even better resistance to pitting corrosion than duplex, so the temperature range they can work at is wider. They are commonly used in the northern seas.
Finally, nickel alloys retain their properties at high temperatures and are generally unaffected by high concentrations of CO2, as well as being less sensitive to chlorides than the above.
At ULMA Advanced Forged Solutions, we have extensive experience in forging CRAs: corrosion-resistant alloys. The combination of our forging processes (closed-die with and without flash, open die, combined forging and free forging), along with our knowledge in material development, allows us to obtain the best mechanical characteristics and corrosion-resistance properties in each of these material qualities.