HEAT TRANSFER TUBE FOR STEAM GENERATOR AND METHOD FOR PRODUCING SAME

摘要

In a heat transfer tube for a steam generator, a surface roughness of an inner surface of the tube is measured along a longitudinal direction and an amount of dimensional variation in a length of 50 mm taken from a measured roughness chart is 4 µm or less and an amount of bend crookedness in a portion of a length of 1000 mm from a tube end is 1 mm or less. Hence, when the tube is produced, an inspection of the tube by an eddy current flaw detection can be conducted at a high S/N ratio and hence an inspection efficiency can be improved, and when the tube is assembled into a heat exchanger, the assembling operation can be easily performed. It is preferable that the heat transfer tube for a steam generator according to the present invention is produced by the steps of cold drawing by use of a high-pressure lubricating oil of 40 MPa or more in pressure; solid solution heat treatment; and straightening by a roll straightening machine. Further, it is preferable that the roll straightening machine is a roll straightening machine using at least five pairs of concave globoidal drum type straightening rolls, each pair of rolls being arranged opposite to each other in a vertical direction and in a crossing manner where directions of rotating shafts cross each other.