Direct Observation of CTOD of Through-Wall Cracks in High Strength Steel Thick Plates

A method of CTOD direct observation of through-wall cracks in high strength steel thick plates was proposed based on analysis of the existing methods. In combination with optical microscopy and electron microscopy and using a multi-sectional method and a image processing technology, curves of CTOD distribution of through-wall cracks along the thickness in high strength steel plates (EQ56 and EQ70) in the thickness of 32 mm were tested by this method. The results show stable and smooth CTOD curves along thickness were obtained by the new method on the base of cost saving.