EFFECT OF NOTCH ANGLE ON FRACTURE TOUGHNESS OF AISI 4340 USING CIRCUMFERENTIALLY NOTCHED BARS

Abstract

In this study the effect of notch angle on fracture toughness (KIC) of AISI 4340 steel is investigated by using circumferentially notched bar method. The specimens have three different notch angles 45°, 60°, 75° and specimen diameters (D) – notch diameters (d) ratio (D/d) keep constant as 1.2. The purpose of the study is determining the effect of notch angle on fracture toughness. Moreover, it shows the advantages of using circumferentially notched bar specimen for fracture toughness determination of metallic materials. The obtained fracture toughness values for different notch diameter are compared with the literature. The result shows that the notch angle has significant effect on the value of fracture toughness (KIC).