A new experimental method on brittle fracture propagation arrest characteristics of welded steel plate

The usual ESSO test has not been successful for the propagation arrest test of the welded part. The paper shows a new type specimen which is a modification of the usual ESSO specimen with regard to notch geometry. It is machined with a chevron notch instead of a usual straight on. The brittle crack that starts from the chevron notch root goes along the weld bead because of higher mechanical constraint near the notch root. Three kinds of steels were here used and welded by three kinds of welding methods: manual welding, submerged arc welding, and electro-gas welding. In order to search the correlation between Charpy impact test results and fracture toughness, Charpy tests by 2mm V-notch and chevron notch were conducted. The transition temperature of chevron notch is higher than that of 2mm V-notch because of higher mechanical constraint. With regard to the brittle fracture propagation arrest characteristics of welded steel plate, the following conclusions were obtained. It is possible to get the propagation-arrest characteristics of welded parts if the chevron notched ESSO specimen is used. Ksub(c) values of welded parts are strongly affected by the welding conditions, for example, heat input, presence of reinforcement, geometry of fusion line. The fracture toughness of the welded part is considerably lower than that of the base metal. The correlation between Ksub(c) values and absorbed energy of Charpy impact test is not in agreement with the WES rule in Japan