An estimate is made of the durability (residual life) of structural elements of oxygen converters, used in steel production, after 1.5–2 years of service. Cracks usually form and grow in these furnaces after this length of time. The crack-resistance characteristics of welded converter elements of normal thickness is determined, making it possible to select the proper steel, evaluate different designs and production techniques, and determine which service conditions are unacceptable. It is shown that in the absence of poorly-fused regions similar to cracks, the life of the structural elements of converters is determined by the properties of the metal in the near-weld zones. Overheating significantly shortens the life of the parts due both to an increase in crack growth rate and a decrease in the fracture toughness of the material.