Making the grade

News and developments in the world of corrosion resistant alloys through the eyes of Corrotherm International

Product Focus: INCOLOY alloy 945 and INCOLOY alloy 945X

11 May 2021

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As the oil and gas industry has to dig deeper to access dwindling reserves, ever more corrosive environments are encountered. But what options do operators have when it comes to materials for downhole oil well hardware?

INCOLOY alloy 945 and INCOLOY alloy 945X are relatively new alloys that have been developed for these most challenging conditions.

These incredibly strong, age-hardenable nickel-iron-chromium alloys are the latest defence in the battle against corrosion. INCOLOY alloy 945 has been specifically designed for oil and gas applications, particularly for downhole oil well hardware. 

The challenge of downhole

The requirements of downhole service are extremely high and becoming ever more demanding.  A downhole hanger must support the weight of the entire oil well casing and must have strength and resistance to general and localised corrosion under sour well conditions. 

Traditionally INCONEL alloys 725, alloy 718, and INCOLOY alloy 925 have met these demanding requirements for tubing hangers, liner hangers, and polished bore receptacles. However, the worldwide increasing demand for oil and gas has meant that more operators are exploring deeper and more corrosive wells, as the easily exploited oil and gas wells decline. 

The design brief

The development of INCOLOY alloy 945 and INCOLOY alloy 945X has been driven by the need from modern operators for a new material that was equal to INCONEL alloy 718 and INCOLOY alloy 925 but that could withstand the higher requirements of deeper drilling.

The design criteria for INCOLOY alloy 945 was built around the need for corrosion resistance at least as good as INCOLOY alloy 925 or INCONEL alloy 718. In addition, the material must not have a tendency to form an inter-granular second phase as it degrades aqueous corrosion resistance. Crucially, any replacement must have a minimum 130ksi yield.  In addition to this, as always, operators also look for cost-effective options.

Other considerations in the design of INCOLOY alloy 945 were the difficulties encountered when trying to produce INCONEL alloy 718 consistently, due to the extremely tight heat treatment window required to achieve the optimal mechanical properties. 

The result: INCOLOY alloy 945 and INCOLOY alloy 945X

To give a benchmark, INCOLOY alloy 925 has a 110 ksi min yield and INCONEL alloy 718 has a 125 ksi min yield. In contrast, INCOLOY alloy 945 has a 130ksi min yield and INCOLOY alloy 945X has a min yield of 140ksi, along with an excellent combination of ductility and impact strength in the solution treated and aged condition.

The alloy was tested under various NACE environments and based on this set of testing the alloy was incorporated into NACE MR0175/ISO-15156 to level IV, and following more recent tests has also passed NACE level VII and level VI at 450F.

If you think INCOLOY alloy 945 or INCOLOY alloy 945X could be the right solution for your installation, please do not hesitate to contact us to talk through your requirements with our team of experts.

Published in Incoloy 945