Abstract: The S32750 duplex stainless steel tube as manufactured by the EAF+AOD+hot-piercing process is made into the Φ25 mm×2 mm U-shaped heat exchanger serviced tube by means of 3-pass cold-rolling，solid solution heat treatment，and stress-relief heat treatment of the bend and the elbow. The results from relevant physical and chemical tests show the said tube possesses such advantages as good surface quality，high dimensional accuracy，and excellent corrosion resistance；the matrix of the tube is of austenite+ferrite microstructure among which the austenite to ferrite phase ratio is 1∶1；the specimens are subjected to the inter-granular corrosion test，the 6%FeCl₃ pitting corrosion test，and the boiling magnesium chloride stress corrosion test，showing that the straight tube and the bend as flattened present no intergranular corrosion crack；and the surface of the straight tube specimen is free of adhesion of any corrosion product； and the corrosion rate is less than 10 mg/（dm²·d）；while the elbow specimen after the penetration inspection presents no crack. All the properties of the product are up to the requirements as specified under applicable standard.