Abstract: The invention provides a non-destructive method of testing a weld made by pressure welding two metal parts (2, 3) at forging temperature. After heating to a temperature of about 1100.degree. C. and applying a forging pressure (F1) to form the weld, the method consists in applying a tensile strength (F2) to the weld perpendicularly to the junction plane (P) between the two ducts (2 and 3) while the weld is still hot at a temperature of, for example, about 600.degree. C., in order to enlarge any defects present at the junction surface (4) and thus make them detectable by a conventional fault detection means.