Abstract: Provided are a large-size diesel exhaust valve and a manufacturing method thereof, which relate to the technical field of manufacturing of large-size diesel exhaust valves for ships. The large-size diesel exhaust valve includes an exhaust valve disc portion made of a 3J40 alloy, and the large-size diesel exhaust valve has the following microstructure: there are ultra-fine grains with a grain size of 10 grade or more, ?-Cr lamellar phases are evenly distributed at grain boundaries of the ultra-fine grains, nickel-lean Cr—Al—Ce particle phases are evenly distributed in a matrix, a single lamella of the ?-Cr lamellar phases has a thickness of less than 140 nm, and the nickel-lean Cr—Al—Ce particle phases have a diameter of less than 10 ?m. The present application solves the technical problem of how to improve the comprehensive mechanical properties and the vibration-damping performance of a large-size diesel exhaust valve simultaneously.

Abstract: Provided are a large-size diesel exhaust valve and a manufacturing method thereof, which relate to the technical field of manufacturing of large-size diesel exhaust valves for ships. The large-size diesel exhaust valve includes an exhaust valve disc portion made of a 3J40 alloy, and the large-size diesel exhaust valve has the following microstructure: there are ultra-fine grains with a grain size of 10 grade or more, ?-Cr lamellar phases are evenly distributed at grain boundaries of the ultra-fine grains, nickel-lean Cr—Al—Ce particle phases are evenly distributed in a matrix, a single lamella of the ?-Cr lamellar phases has a thickness of less than 140 nm, and the nickel-lean Cr—Al—Ce particle phases have a diameter of less than 10 ?m. The present application solves the technical problem of how to improve the comprehensive mechanical properties and the vibration-damping performance of a large-size diesel exhaust valve simultaneously.