Heat transfer tube for steam generator and method for producing the same

A method for producing a heat transfer tube for a steam generator, the method comprising:

• a step of providing a tube;
• a step of applying cold drawing to the tube by using a high-pressure lubricating oil of 40 MPa or more in pressure;
• after the step of applying cold drawing to the tube, a step of applying a solid solution heat treatment to the tube;
• and
• after the step of applying a solid solution heat treatment to the tube, a step of straightening the tube by using a roll straightening machine,
• wherein
• the roll straightening machine includes at least five pairs of concave globoidal drum type 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, a stand interval being set at 300 mm or less;
• in the step of applying straightening the tube, offsetting that is formed by three points literally along a tube axial centerline as being crossing positions of at least successive three pairs of upper and lower straightening rolls of the roll straightening machine allows η expressed by Formula (1) described below to satisfy 0.9×10−3 or more and to ensure an offset amount of 5 mm or less:
• η=1/R×(d/2) (1)
• where given that an outside diameter of the tube is d (mm) and a stand interval of the roll straightening machine is L (mm) and an offset amount is 8 (mm), R=(δ2+L2)/2δ is established.