TWI Industrial Member Report Summary 308/1986
By B Hayes, I M Norris and O L Towers
The Charpy V notch test is widely used in quality control for assessing the toughness of materials. The test is both simple and cheap to perform which makes it attractive. In welded components the toughness of the weld metal is of great concern as defects, which may initiate brittle fracture, can exist in this region. However, in narrow weldments such as those produced by the electron beam, laser and friction welding processes, it may not be possible to obtain a meaningful measure of toughness from the Charpy V notch test due to crack deviation out of the weld metal into the parent plate. For the test result to be a valid measure of the weld metal or fusion line properties, the crack path must follow the joint line. This study investigated simple modifications made to the standard Charpy test specimen with the aim of confining the fracture path to one plane. The modifications considered were side-slitting the test pieces to various depths and chevron notching. Tests were made on specimens taken from an electron beam (EB) weld, a laser weld and two orbital friction welds.