THE DYNAMIC FRACTURE-TOUGHNESS PROPERTIES OF A FE-40 CR ALLOY - THE EFFECT OF INTERSTITIAL SOLUTES

The present paper describes a series of experiments aimed at assessing the influence of interstitial solute elements, carbon, nitrogen and o xygen on the dynamic fracture toughness, K-Id, characteristics of an i ron-40% chromium super-ferritic stainless steel. It was observed that additions of carbon and nitrogen significantly decreased K-Id while ab ove a certain level the toughness properties were insensitive to chang es in composition. The additions of oxygen up to 0.065% did not signif icantly affect the dynamic fracture toughness of iron-40% chromium all oys. It has been demonstrated that the dynamic fracture toughness test is a convenient and relatively accurate method of assessing the tough ness properties of this particular alloy. The fracture toughness value s can be related to Charpy impact values and can provide an easy metho d for the fracture toughness screening of materials without performing the instrument impact test.