Weld-decay and stress-corrosion cracking developed in several similar all-welded vessels fabricated from austenitic stainless steel. During a periodic examination cracks were revealed at the external surface of one of the vessels. External patch welds had been applied at these and several other corresponding locations. Cracks visible on the external surface developed from the inside in a region close to the toe of the internal fillet weld to the deflector plate, and another deep crack associated with a weld cavity is visible slightly to the right of the main fissure. Microscopic examination revealed that precipitation of carbides at the grain...