Studies of the effect of thickness on the fracture toughness of grade 300 maraging steel, part 1.

Abstract

A series of tests was carried out using the ASTM fracture toughness test standards as a basis to determine the variation in fracture toughness of maraging steel (grade 300) of thickness ranging from 10 to 1 mm. Although these standards are not strictly applicable to maraging steels of the lower thicknesses in this range, they yield a measure of fracture toughness which can be used to predict safe operating stresses for thin walled the structures. A maximum fracture toughness of approximately 90 MPa m was obtained at 1 mm, the minimum thickness examined. The plane strain fracture toughness was approximately 58 MPa m at thicknesses greater than 5 mm.