Development of Strain-based Designed X80M HD2 Pipeline Steel and UOE Pipe

Since there exist several active fault zones in the Fourth West-East Gas Transmission Pipeline Project the Φ1 219 mm×33 mm strain-based designed X80M HD2 linepipe with required high performance is needed. Accordingly corresponding product design，trial production and performance analysis are carried out. The results show that the steel pipe as made of the pipeline steel designed with the ferrite + bainite dual phase structure features low yield to strength ratio， high uniform elongation and high stress ratio，having been properly meet the performance requirements of the strain-based designed steel pipe for the above mentioned project. And the further analysis shows that the forming process is regarded the one during which the related deformation performance of the steel pipe most obviously decreases，and the aging process has little effect on the related properties. The deformation indexes of the post-aging steel pipe like longitudinal uniform elongation and the stress ratio，etc. can be ensured to meet applicable technical requirements by means of getting the post-aging yield strength between 530 MPa and 582 MPa，and the yield ratio ≤0.85 via proper control.