What are the types of Hastelloy alloys?

As a representative of high-performance nickel based corrosion-resistant alloys, Hastelloy has formed multiple series of models by adjusting the alloy element ratio, each with its unique performance focus and application scenarios. The most widely used models in industry currently include the C series, B series, G series, and a few special models, which demonstrate excellent adaptability in different corrosive environments with precise composition design. ​

The C-series Hastelloy alloy is the most widely used category, with the C276 model being the industry benchmark. It is based on nickel, with a certain proportion of chromium, molybdenum, and a small amount of tungsten added, forming a dual corrosion resistance to oxidizing and reducing media. This alloy exhibits excellent performance in mixed acid environments such as sulfuric acid, hydrochloric acid, and phosphoric acid, while also resisting pitting and crevice corrosion caused by chloride ions. Therefore, it is widely used in equipment such as chemical reaction vessels and flue gas desulfurization devices. The C22 model has optimized the chromium content based on C276, further enhancing its oxidation resistance and making it more suitable for high-temperature oxidation and corrosion conditions, such as heat exchange components in waste incineration power generation equipment. The C2000 model enhances its corrosion resistance to sulfuric acid and hydrofluoric acid by introducing copper elements, making it the preferred material in the field of wet metallurgy. ​

The B-series Hastelloy alloy has the core advantage of resistance to reducing medium corrosion, and the B2 model is a typical representative of this series. Its composition contains a high proportion of molybdenum and almost no chromium. This design makes it exhibit irreplaceable corrosion resistance in reducing environments such as pure hydrofluoric acid and sulfuric acid, and is often used in high-temperature and high-pressure pipelines in coal chemical industry. The B3 model reduces the intergranular corrosion risk in the welding heat affected zone by reducing impurities such as carbon and silicon, and is widely used in harsh hydrogenation reaction devices. Compared to the C series, the B series has poor stability in oxidative environments, so it is necessary to strictly match the characteristics of the medium when using it. ​

The G series Hastelloy alloy focuses more on comprehensive performance balance, and the G30 model is one of the best among them. It combines a certain proportion of chromium, molybdenum, and copper, retaining its resistance to oxidizing media and enhancing its corrosion resistance to reducing acids, especially in complex chemical environments containing chloride ions. It is commonly used as an ammonia synthesis tower component in fertilizer production. The G35 model refines the grain size by adding niobium element, improving the high-temperature strength of the alloy and making it suitable for organic acid treatment equipment operating at high temperatures. ​

In addition to the mainstream models mentioned above, there are also some special categories of Hastelloy alloys. N10276 (ASTM number C276) is an internationally recognized standardized model that ensures consistent performance of products from different manufacturers. The D205 model, due to its high silicon content, exhibits unique advantages in high-temperature and dry chlorine gas environments and is commonly used in chlorine gas treatment equipment in the chlor alkali industry. These models together constitute the complete system of Hastelloy alloys, providing precise material solutions for different industrial scenarios. ​

When choosing a Hastelloy alloy model, it is necessary to comprehensively consider factors such as medium type, temperature and pressure, and mechanical performance requirements. With the development of material technology, new models are still being optimized, but their core design logic always revolves around the principle of “precise matching of corrosive environments”, which is also the key to maintaining long-term stable operation of Hastelloy alloys in extreme working conditions. ​