Industrial Experiment of the Online Accelerated Cooling for 27SiMn Seamless Steel Pipe

An online accelerated cooling equipment for seamless steel pipe is introduced, which can cool the inner and outer surfaces of seamless steel pipe simultaneously. Through industrial experiments, the 27SiMn test steel pipe is subjected to an online accelerated cooling process with a final cooling temperature of 510–590 °C. The outer diameter, wall thickness, and length of the test steel pipe are 180, 20, and 13000 mm, respectively. This process successfully upgrades its mechanical property grade from the original J55 to the N80 grade, with yield strength of 603–630 MPa, tensile strength of 830–839 MPa, elongation of 22–24%, and impact toughness of 35–37 J at 0 °C.