Hastelloy G35

Hastelloy G35: A High-Performance Material for Demanding Applications

Hastelloy G35 is a nickel-chromium-molybdenum alloy that provides superior resistance to corrosion, pitting, and crevice corrosion in highly aggressive chemical environments. It has been specifically designed for use in applications where the conditions are too severe for conventional nickel alloys to perform adequately. This article will discuss the key features of Hastelloy G35, including its chemical composition, mechanical properties, heat treatment, and applications.

Chemical Composition

Hastelloy G35 contains approximately 56% nickel, 23% chromium, 5% iron, 4% molybdenum, and smaller amounts of cobalt, tungsten, and copper. The alloy’s high nickel content gives it excellent resistance to both reducing and oxidizing chemical environments, while the molybdenum provides additional resistance to localized corrosion caused by chlorides and other halogens.

Mechanical Properties

Hastelloy G35 possesses outstanding mechanical properties, including high tensile strength, good ductility, and excellent toughness at both ambient and elevated temperatures. The alloy’s yield strength is approximately 480 MPa, with a tensile strength of 930 MPa. Its hardness ranges from 160 to 200 HB, depending on the heat treatment applied.

Heat Treatment

Hastelloy G35 can be heat-treated using a variety of techniques to achieve specific properties. For example, annealing at temperatures between 1050 and 1150°C for one hour can improve the alloy’s ductility and toughness. Solution heat treatment at 1040°C for one hour, followed by air cooling or rapid quenching, can improve the alloy’s strength and hardness.

Applications

Hastelloy G35 is widely used in a range of demanding applications, including chemical processing, pollution control, pulp and paper production, and waste incineration. Its superior resistance to oxidizing and reducing acids, such as sulfuric, hydrochloric, and phosphoric acid, makes it an excellent choice for use in reaction vessels, heat exchangers, evaporators, and other process equipment.

Hastelloy G35 is available in a range of forms, including plate, round bar, pipe, strip, and wire rod, making it suitable for a variety of fabrication methods. The alloy can be easily welded using conventional techniques, and its excellent formability allows for the production of complex shapes and structures.

Process Standards

Hastelloy G35 is manufactured according to a range of international standards, including ASTM B575 for plates, ASTM B622 for seamless pipes, and ASTM B626 for welded pipes. These standards ensure that the material meets specific requirements for chemical composition, mechanical properties, and dimensional tolerances.

Conclusion

Hastelloy G35 is a high-performance alloy that offers exceptional resistance to corrosion, pitting, and crevice corrosion in aggressive chemical environments. Its unique combination of properties makes it an ideal choice for a range of demanding applications, from chemical processing to pollution control. When selecting Hastelloy G35 for your specific application, it’s important to consider factors such as chemical compatibility, temperature and pressure requirements, and the method of fabrication. With proper selection and handling, this versatile material can provide years of reliable service in even the most challenging conditions.