HAYNES® 625SQ® alloy (UNS N06626) is a solid-solution strengthened superalloy. It is a modification of HAYNES 625 alloy developed to enhance resistance to fatigue at temperatures up to approximately 1200°F (649°C). The alloy composition is tightly controlled to very low levels of carbon, silicon, and nitrogen.

Primary melting is by vacuum induction melting, followed by consumable electrode practice using electroslag remelting. During processing, the grain size is controlled to ASTM #5 or finer.

HAYNES® 625SQ® alloy is readily fabricated and welded using practices common to HAYNES® 625 alloy. 625SQ® alloy sheet and strip find application in aerospace, automotive, and chemical process industry bellow, expansion joints, and fabrications wher fatigue resistance, strength, and corrosion resistance are required.