Inconel 738 is a nickel-chromium-cobalt (Ni-Cr-Co) superalloy primarily used in high-temperature applications like gas turbine components. Its equivalents are defined by similar chemical composition, mechanical properties (especially high-temperature strength and creep resistance), and application scenarios. The main substitutes are listed below:
Execution standards for Inconel 738 specify requirements for its chemical composition, mechanical properties, heat treatment, testing methods, and dimensional tolerances. These standards are issued by international organizations, national authorities, and industry associations to ensure product consistency and performance. The key standards are categorized as follows:
ISO 12165: Nickel-based superalloys for high-temperature applications
This standard defines the general requirements for nickel-based superalloys, including Inconel 738. It covers chemical composition limits, tensile properties at room and high temperatures, creep rupture testing procedures, and quality control criteria for forgings and castings.
ASTM B-166: Standard Specification for Nickel-Chromium-Iron Alloys (UNS N06600, N06601, N06603, N06690, N06693, N06025, N06045, and N06696) Plate, Sheet, and Strip
Although primarily for sheet/plate products, it references Inconel 738's chemical composition ranges and provides guidelines for room-temperature tensile testing and corrosion resistance evaluation.
AMS (Aerospace Material Specification) Standards
AMS standards are widely adopted in the aerospace industry for high-performance materials.
AMS 5662: Specifies the requirements for Inconel 738 castings, including chemical composition, tensile strength (minimum 1240 MPa at room temperature), yield strength (minimum 860 MPa), and creep rupture strength (minimum 345 MPa at 850°C for 1000 hours).
AMS 5663: Covers Inconel 738 forgings, with stricter dimensional tolerances and additional fatigue testing requirements for aerospace-grade components.
