Alloy 925 and Alloy 718 differ in composition, but because Alloy 925 reaches similar tensile strength it is increasingly used as a lower-cost substitute in many oil and gas applications.
Composition
Alloy 925 is a nickel-based alloy whose largest single element is nickel at 38-46% of the total, with iron, chromium and molybdenum at lower proportions. By comparison, Alloy 718 contains 50-55% nickel, with similar levels of chromium and molybdenum. As nickel is an expensive addition, the higher nickel content of Inconel 718 raises its price relative to Incoloy 925 by up to 20%.
Mechanical properties
The mechanical properties of Incoloy 925 are quite similar to Inconel 718, as both achieve high strength through precipitation strengthening. Small additions of titanium, aluminium and niobium form fine precipitates throughout the metal during a secondary heat treatment. These precipitates help to ‘pin’ the microstructure under load, increasing strength and toughness.
Langley Alloys stocks Alloy 718 as round bars from 5/8”-10” diameter (15.87-254mm). Alloy 925 is less readily available in the smallest diameters, so our stock typically starts at 4”-10” (101.6-254mm) diameter.