Hastelloy X: A Guide to Composition, Properties, and Applications 

Hastelloy X is a nickel-chromium-iron-molybdenum superalloy renowned for its exceptional combination of high-temperature strength, oxidation resistance, and fabricability. This solid-solution-strengthened alloy maintains its performance integrity in some of the most demanding industrial environments, making it a critical material for high-stakes applications. Its unique formulation provides reliable service in aerospace, industrial furnace, and gas turbine engine components where lesser materials would fail. 

This guide provides a detailed technical overview of Hastelloy X, covering its precise chemical composition, mechanical and physical properties, equivalent standards, and primary applications. For procurement engineers, project managers, and designers, understanding these characteristics is essential for specifying a material that guarantees performance, safety, and long-term value in severe-service conditions. 

Key Properties and Performance Characteristics 

Hastelloy X alloy stands out for a set of properties that make it uniquely suited for high-temperature, high-stress environments. Its performance has been proven through decades of service in critical industrial and aerospace applications. When you specify this alloy, you are selecting a material engineered for durability and reliability. 

• Outstanding Oxidation Resistance: The alloy exhibits exceptional resistance to oxidizing atmospheres up to 1200°C (2200°F). The high chromium content facilitates the formation of a protective, adherent oxide scale that shields the base metal from further attack, ensuring long service life in combustion zones and industrial heating environments. 
• High-Temperature Strength: Hastelloy X is not a precipitation-hardening alloy; its strength is derived from solid-solution strengthening by molybdenum. It retains good creep and rupture strength at temperatures up to 870°C (1600°F), making it dependable for load-bearing components in jet engines and industrial furnaces. 
• Excellent Fabricability: Despite its high strength, Hastelloy X offers excellent forming and welding characteristics. It can be readily fabricated into complex components using standard techniques, providing design flexibility without compromising material integrity. 
• Resistance to Stress-Corrosion Cracking: The high nickel content provides inherent resistance to chloride-induced stress-corrosion cracking (SCC), a common failure mode for many stainless steels in petrochemical and marine environments. This makes Hastelloy X a reliable choice for heat exchangers and process piping. 
• Good Ductility After Prolonged Aging: After long-term exposure to temperatures between 540°C and 870°C (1000°F and 1600°F), Hastelloy X maintains adequate ductility. This characteristic is vital for components that must endure thermal cycling without becoming brittle.