A Detection Method of Rolled Thread Streamline of Inconel 718 Alloy Bolts

Inconel 718 alloy bolts are a high strength bolts commonly used in the aeroengine, and they usually adopt rolled thread technology. The streamline of bolts and threads directly affects the quality and service life of the bolts, so streamline detection is particularly important. Through test, it is found that grain growth and δ phase (Ni₃Nb) precipitation can be achieved by secondary solution and aging treatment of Inconel 718 alloy bolts. And then the streamline of Inconel 718 alloy bolts and threads can be clearly displayed by etching in HNO₃+HF solution for 1 h.