ASME B31T:2015 pdf free download – Standard Toughness Requirements for Piping
3.7.2.2 Test Specimens. The weld procedure qual- ification impact test specimens shall be Charpy V-notch specimens prepared and tested in accordance with the requirements in ASME BPVC Section IX. A test shall consist of five specimens, all of which shall be tested at or below the design minimum temperature. The highest and lowest values of these specimens shall be disre- garded, and the average value of the three remaining specimens shall equal or exceed the impact value required for the base metal to be welded in production. The impact specimen representing the weld deposit shall be located so that the longitudinal axis of the speci- men is at least 0.25t from a surface, where t is the thick- ness of the test weld and, where the thickness of the test assembly permits, not less than 10 mm ( 3 ⁄ 8 in.) from the weld surface of the test assembly. In addition, when the postweld heat treatment temperature exceeds the maximum temperature specified bythe code referencing this Code, and the test assembly is cooled at an acceler- ated rate, the longitudinal axis of the specimen shall be a minimum of t from the edge of the test assembly. The specimen shall be transverse to the longitudinal axis of the weld with the area of the notch located in the weld. The length of the notch of the Charpy V-notch specimen shall be normal to the surface of the weld. Specimens representing the heat-affected zone shall be taken from the welding procedure qualification test assemblies in accordance with (a) through (c) below.
(a) If the qualification test material is in the form of a plate or a forging, the axis of the weld shall be oriented in the direction parallel to the principal direction of rolling or forging.
(b) The specimens shall be removed from a location as near as practical to a depth midway between the surface and center thickness. The coupons for heat- affectedzone impactspecimensshallbe takentransverse to the axis of the weld and etched to define the heat- affected zone. The notch of the CVN specimen shall be cutapproximately normal to the material surface in such a manner as to include as much heat-affected zone as possible in the resulting fracture. Where the material thickness permits, the axis ofa specimenmay be inclined to allow the root of the notch to align parallel to the fusion line. When a grain-refining heat treatment is not performed on welds made by the electroslag or electro- gas welding process, the notch for the impact specimens shall be located in the grain-coarsened region.
(c) For the comparison of heat-affected zone values with base material values, CVN specimens shall be removed from the unaffected base material at approxi- mately the same distance from the base material surface as the heat-affected zone specimens. The axis of the unaffected base material specimens shall be parallel to the axis of the heat-affected zone specimens, and the axis of the notch shall be normal to the surface of the base material.