316L stainlesss steel coil tubing suppliers

For demanding applications exposed to corrosive liquids such as seawater and chemical solutions, engineers have traditionally turned to high valence nickel alloys such as Alloy 625 as the default choice. Rodrigo Signorelli explains why high nitrogen alloys are an economical alternative with increased corrosion resistance.

316L stainlesss steel coil tubing suppliers

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        Quality and certification determine the choice of materials for systems such as plate heat exchangers (PHEs), pipelines and pumps in the oil and gas industry. Technical specifications ensure that assets provide continuity of processes over a longer lifecycle while ensuring quality, safety and environmental protection. This is why many operators include nickel alloys such as Alloy 625 in their specifications and standards.
        Currently, however, engineers are forced to limit capital costs, and nickel alloys are expensive and vulnerable to price fluctuations. This was highlighted in March 2022 when nickel prices doubled in a week due to market trading, making headlines. While high prices mean nickel alloys are costly to use, this volatility creates management challenges for design engineers as sudden price changes can suddenly impact profitability.
        As a result, many design engineers are now willing to replace Alloy 625 with alternatives even though they know they can rely on its quality. The key is to identify the right alloy with the appropriate level of corrosion resistance for seawater systems and provide an alloy that matches the mechanical properties.
        One eligible material is EN 1.4652, also known as Outokumpu’s Ultra 654 SMO. It is considered the most corrosion resistant stainless steel in the world.
        Nickel Alloy 625 contains at least 58% nickel, while Ultra 654 contains 22%. Both have roughly the same chromium and molybdenum content. At the same time, Ultra 654 SMO also contains a small amount of nitrogen, manganese and copper, 625 alloy contains niobium and titanium, and its price is much higher than that of nickel.
       At the same time, it represents a significant improvement over 316L stainless steel, which is often considered the starting point for high performance stainless steels.
        In terms of performance, the alloy has very good resistance to general corrosion, very high resistance to pitting and crevice corrosion, and good resistance to stress corrosion cracking. However, when it comes to sea water systems, stainless steel alloy has an advantage over alloy 625 due to its excellent resistance to chloride environments.
        Sea water is extremely corrosive due to its salt content of 18,000–30,000 parts per million of chloride ions. Chlorides present a chemical corrosion risk for many steel grades. However, organisms in seawater can also form biofilms that cause electrochemical reactions and affect performance.
        With its low nickel and molybdenum content, the Ultra 654 SMO alloy blend delivers significant cost savings over traditional high specification 625 alloy while maintaining the same level of performance. This usually saves 30-40% of the cost.
        In addition, by reducing the content of valuable alloying elements, stainless steel also reduces the risk of fluctuations in the nickel market. As a result, manufacturers can be more confident in the accuracy of their design proposals and quotations.
        The mechanical properties of materials are another important factor for engineers. Piping, heat exchangers, and other systems must withstand high pressures, fluctuating temperatures, and often mechanical vibration or shock. The Ultra 654 SMO is well positioned in this area. It has high strength similar to alloy 625 and is significantly higher than other stainless steels.
       At the same time, manufacturers need formable and weldable materials that provide immediate production and are readily available in the desired product form.
       In this regard, the alloy is a good choice because it retains good formability and good elongation of traditional austenitic grades, making it ideal for designing strong and lightweight heat exchanger plates.
       It also has good weldability and is available in various forms including coils and sheets up to 1000mm wide and 0.5 to 3mm or 4 to 6mm thick.
        Another cost advantage is that the alloy has a lower density than alloy 625 (8.0 vs. 8.5 kg/dm3). While this difference may not seem significant, it reduces tonnage by 6%, which can save you a lot of money when buying in bulk for projects like trunk pipelines.
        On this basis, lower density means the finished structure will be lighter, making it easier to logistic, lift and install. This is especially useful in subsea and offshore applications where heavy systems are more difficult to handle.
       Given all the features and benefits of Ultra 654 SMO – high corrosion resistance and mechanical strength, cost stability and the ability to accurately plan – it clearly has the potential to become a more competitive alternative to nickel alloys.