Introduction:
Alloys 625 and 625Plus possess excellent corrosion resistance, oxidation resistance, and high strength, along with good formability and toughness. The main difference between 625 and 625Plus lies in the chemical composition: 625Plus slightly reduces chromium, molybdenum, and niobium content, adds titanium, and lowers carbon to an ultra-low level. Alloy 625 increases its strength through cold working after solution treatment, while 625Plus achieves higher strength through one or two aging treatments following solution treatment. Both alloys are suitable for applications requiring a combination of high corrosion resistance and high strength.

Applications:
Due to their high corrosion resistance and good high-temperature strength, alloys 625 and 625Plus can serve as both corrosion-resistant and heat-resistant materials. For corrosion-resistant applications, Alloy 625 is primarily used in nitric acid, mixed acids (HNO₃ + H₂SO₄, HNO₃ + HF), wet phosphoric acid containing H₂SO₄ and F⁻/Cl⁻, and in seawater corrosion environments. Alloy 625Plus, besides having comparable corrosion resistance to 625 in acidic media and seawater, also exhibits excellent resistance to chloride and sulfide stress corrosion, as well as pitting and crevice corrosion even in the aged state. Both alloys are suitable for manufacturing towers, tanks, vessels, pipelines, reactors, heat exchangers, valves, and other equipment requiring both corrosion resistance and high strength.