Ultra Alloy 825: The Optimal Choice for Oil and Gas Industry
Our customers in the oil and gas industry are increasingly turning to Ultra Alloy 825 according to our Ultra Alloy 825 product manual, as it demonstrates exceptional performance in demanding operating environments, particularly in “sour” sulfur-containing environments.
Ultra Alloy 825 is a titanium-stabilized nickel-based alloy with copper addition. It contains approximately 40% nickel and has an austenitic structure.
Key Material Properties
Titanium stabilization combined with low carbon content reduces the risk of chromium carbide precipitation that may form in the stainless steel sensitization temperature range, making Ultra Alloy 825 less sensitive to intergranular corrosion compared to other stainless steels that may experience this issue. Additionally, excellent tolerance in sulfur-containing environments is a major advantage of Ultra Alloy 825. When stainless steel is exposed to hydrogen sulfide (H2S) environments, Ultra Alloy 825 still maintains superior resistance to sulfide stress cracking (SSC).
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Industry Challenge and Solution
As natural gas’s share in the global energy structure increases annually, and a significant portion of global natural gas reserves consists of sour gas containing large amounts of hydrogen sulfide, there is an increasing need to consider the material selection requirements for sour gas environments. The presence of hydrogen sulfide presents a particular challenge as it easily causes steel corrosion and sulfide stress corrosion cracking (SSC), which is particularly common in oil and gas pipelines.
Sour gas fields, in addition to corrosive environmental conditions, may require extraction at temperatures up to 260°C and high pressures up to 1,700 bar. Therefore, material selection becomes a critical factor for the success of the entire extraction operation. It is crucial to achieve cost-effectiveness while meeting corrosion resistance and strength requirements to ensure reliable operation over a 30-year service life. This is the unique advantage that Ultra Alloy 825 can provide.
Exceptional Performance
Corrosion Resistance
Ultra Alloy 825 exhibits excellent corrosion resistance in many acids, such as sulfuric acid, phosphoric acid, nitric acid, and organic acids. In solutions containing reducing acids, the addition of molybdenum (Mo) and copper (Cu) further enhances its corrosion resistance. The alloy also has good corrosion resistance to alkaline solutions containing sodium and potassium hydroxide.
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Mechanical Properties
Ultra Alloy 825 has good mechanical properties at medium-high temperatures below 540°C and at low temperatures. In terms of pitting and crevice corrosion resistance, Ultra Alloy 825 outperforms Supra 316L/4404 and Ultra 254 SMO stainless steel commonly used in harsh corrosive environments. The high nickel content also ensures its resistance to stress corrosion cracking in chloride and alkaline environments.
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Like other types of nickel-based alloys, Ultra Alloy 825 has good ductility and can be processed and welded using conventional methods.
Consistency
The stable quality and high performance of Ultra Alloy 825 are crucial. Beyond this, our emphasis on supply chain management is also key to our successful brand reputation enhancement in the oil and gas industry.
Manufacturing Advantages
While competitors are mainly limited by expensive ingot casting processes, our continuous casting production process improves the cost competitiveness of Ultra Alloy 825. We offer various types of products, whether cold-rolled or hot-rolled, capable of reaching widths up to 1500mm. Although stainless steel coils still have certain tolerances, they help pipe manufacturers improve productivity.
When we learned about customer needs for stainless steel plates, we developed medium and heavy plates with thicknesses up to 42mm to meet customer product supply consistency requirements.
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We also pay special attention to delivery, such as buffer inventory set up at factories, which helps ensure timely delivery of Alloy 825 and reduce delays – this is key to establishing solid partnerships with major players in the oil and gas industry.
Versatile Applications
Subsea Pipelines
Ultra Alloy 825 is widely used in subsea pipelines, such as covering the inner diameter of pipelines with a thin layer of corrosion-resistant alloy (CRA), while the outer shell uses carbon steel to provide mechanical strength.
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Weld Overlay Applications
Some customers use Ultra Alloy 825 for weld overlay, a technique that welds a thin layer of Ultra Alloy 825 onto components made of carbon steel or other materials. This not only shortens delivery time but also reduces costs, commonly used for constructing large vessels or metal components requiring high-specification materials, such as pipelines, valves, flanges, connectors, elbows, and pipe components.
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Industrial Applications
Fractionation towers were the first practical application of Ultra Alloy 825, separating crude oil into fractions with different boiling points. It is also used in manufacturing vane inlet devices and sour gas processing applications.
Air-cooled heat exchangers are a rapidly growing application, also known as air fin coolers, helping to remove heat generated during production processes and playing a crucial role in refineries. In harsh environments where other materials fail prematurely, Ultra Alloy 825 is the ideal choice.
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Professional Expertise
Ultra Alloy 825 has now become the “preferred” alternative to stainless steel, ensuring equipment safety, reliability, and long service life in demanding oil and gas applications. Nevertheless, we still recommend thorough analysis and testing of specific conditions before making final material selection. In this regard, our expert team can provide professional guidance and advice.
Conclusion
Ultra Alloy 825 represents the pinnacle of material engineering for oil and gas applications, offering unmatched performance in sour gas environments, superior corrosion resistance, and reliable long-term service. Its versatility, consistent quality, and cost-effective manufacturing make it the optimal choice for modern petrochemical operations seeking to maximize efficiency while ensuring safety and durability.
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