Hastelloy C276 (EN 2.4819): Preferred material for "reducing acid + chloride ion" conditions;
Hastelloy C22 (EN 2.4602): Preferred material for oxidizing acids (HNO₃, FeCl₃, CuCl₂), oxidizing chlorides, and mixed acids (oxidizing component + reducing component);
Hastelloy B3 (EN 2.4600): Preferred material for reducing acids (HCl, dilute H₂SO₄, acetic acid, phosphoric acid, formic acid), prohibited for oxidizing media;
Hastelloy C4 (EN 2.4610): Preferred material for fluorine-containing media, where post-weld heat treatment is not possible, and for long-term thermal cycling conditions.