Influence of Heat Treatment Temperature on Super Duplex Steel UNS S32760 Tubular Products

Super duplex steel UNS S32760 seamless steel pipes are made by 6 300 t horizontal extrusion press and solution treated at different temperatures.The influence of solution treatment temperature on metallographic structure, mechanical properties and anti-corrosion performance is studied.The results show that with the increasing of solution treatment temperature, the content of ferrite phase(α phase) in UNS S32760 gradually increases and that of austenite phase(γ phase) gradually decreases, the tensile strength and the elongation basicly remain the same, the yield strength gradually increases and the impact energy also shows an increasing tendency.When the solution treatment temperature is 1 100℃, the ratio between α phase and γ phase is about 1:1, the pitting corrosion rate is at the lowest of 0.031 mm/a and so the pitting corrosion resistance performance of the product is at its best.