Optimum Methods of Grain Display of PH13-8Mo Precipitation-hardening Stainless Steel for Aviation

It is invalid that the grain boundary shown from the specimen of PH13-8Mo precipitation-hardening stainless steel for aviation after heat treatment of direct hardening and etched by normal stainless steel etching solution. Comparison oxidation method with direct hardening method by various corrosion, the results show that oxidation method lead to the real, integrity, clear grain morphology. It is a valid, convenient and environmental method for grain size evaluation of steel PH13-8Mo; 92 mL HCl+5 mL H₂SO₄+3 mL HNO₃ immersion at room for 1 min or 1 g KMnO₄+10 mL H₂SO₄+100 mL H₂O thermal etching for 2 min by direct hardening method can produce clear grain boundaries.