Abstract: A method for producing an autogenous welded tubular metal article having a substantially uniform grain size, including the weld-affected area thereof. This is achieved by applying to the metal article a series of cold reduction and annealing operations that in combination render the grain size of the weld-affected area uniform with respect to the remainder of the cross-section of the article, and particular the visual appearance of the cross-section.

Abstract: A method for producing an autogenous welded tubular metal article having a substantially uniform grain size, including the weld-affected area thereof. This is achieved by applying to the metal article a series of cold reduction and annealing operations that in combination render the grain size of the weld-affected area uniform with respect to the remainder of the cross-section of the article, and particular the visual appearance of the cross-section.

Abstract: An austenitic stainless steel article, preferably in the form of a tubing. The article has a passivated surface layer, which in the case of a tubing is on the interior surface of the tubing. The passivated surface layer has an oxide component having Fe2O3 and Cr2O3 and a metal component of Fe with zero valence and Cr with zero valence. The ratio of the oxide component to the metal component is in excess of 8:1.

Abstract: A process for making tubes, channels and other relatively thin-walled elongated shapes having a unique degree of dimensional accuracy and stability in which the part after being shaped and only approximately sized is mounted on a mandrel having a larger coefficient of thermal expansion than the part. The mandrel and the part are connected at their opposite ends so that expansion of the mandrel first causes elongation and concomitant lateral shrinkage of the part and then lateral expansion of the part so that it is triaxially hot worked to bring it to its final hot size from which the part contracts to its finished size at room temperature. For maximum freedom from residual stresses and dimensional stability thermal sizing is carried out by heating to a temperature at least just above the recrystallization temperature of the part.