This test is performed to reveal internal imperfections such as slag inclusion, lack of fusion, incomplete penetration, porosity, etc in a fillet weld.  A fillet weld specimen is fractured along an artificial notch that is intentionally machined on the centre line of the fillet weld specimen to facilitate fracture in the centre of the weld. The fractured specimen cross section is then visually examined for imperfections. AS 2205.4.2 and ASME IX QW 182 are some of the common standard method utilised to perform this test.