What core alloying elements determine Hastelloy’s anti-corrosion performance?

Molybdenum is the core element resisting reducing acids like hydrochloric acid, while chromium forms dense passive films to defend oxidizing media such as nitric acid. Tungsten further strengthens local corrosion resistance against pitting and crevice corrosion, and trace iron improves processing performance. Different element ratios create differentiated grades: high-molybdenum B series targets pure reducing acid, and high-chromium C series adapts to mixed acid and flue gas desulfurization environments, meeting diverse harsh working demands.