Actually the very high strength Maraging steels are not necessarily tough. Their high tensile strength can come at the cost of low fracture toughness, also known as critical stress intensity factor. Brittle fracture can then occur due to small initial flaws, cracks for example, at relatively low stress levels.
The tradeoff between fracture toughness and tensile strength is part of the design selection process for steel, as typically higher values for one are associated with lower values for the others.
Pressure vessel design text books sometimes use failures of Maraging steel pressure vessels as examples of the results of steel selection focusing on tensile strength, while neglecting fracture toughness required due to possible initial flaws.
Last edited by vangulil; 02/16/14 11:14 PM.
