Hsl450s Subsea Pipeline Tube Development,

With the rapid development of the offshore oil industry, the manufacturers of steel pipe have paid more attention to the design and development of the submarine pipe lines with high strength, high toughness, good corrosion and low temperature resistance. While, hindered by the production equipments and techniques, it is very difficult to produce this kind of products, and little manufacturers can do it in China. As a result, almost all the pipes used in the past were imported from abroad, and the national yield is very low.Based on failure analysis theory and the manufacture experience of the Hengyang Hualing Steel Tube (Group) Co Ltd, we have developed HSL450S submarine pipe lines with good weldability, high tensile strength and anti-impact toughness after technical investigation, composition design and process optimization. Moreover, we characterized the chemical composition, mechanical properties and microstructure of the materials, and evaluated the process of corrosion resistance and cyclic welding. The results show:1. The composition design is perfect and has good adaptability with the production process, meeting the demand of GB/T9711.3-2005. The alloy materials have good weldability and corrosion resistance to H₂S and CO₂.2. The as-obtained HSL450S submarine pipes have perfect geometric accuracy and surface quality. The chemical composition and macro quality of the cast round are satisfying. The optimized processing parameters are:a. The perforation and rolling process: cast round withΦ150 mmâ†'heating to 1280℃â†'perforation toΦ142×21 mm (draw ratio of 2.21 and surface shrinkage deformation of 54.75%)â†'three-roll rolling toΦ118×14 mm (draw ratio of 1.74 and surface shrinkage deformation of 42.53%)â†'heating to 94℃â†'slight stretch reducing toΦ102×14 mm (draw ratio of 1.18 and surface shrinkage deformation of 15.25%).b. The heat treatment process: quenching process (970℃/ diacranterian burden distribution, stepping period-60s, tapping interval-120 s) and tempering process (570℃/diacranterian burden distribution, stepping period-60 s, tapping interval-120 s).3. The mechanical properties of the as-obtained pipes can meet the internal controlled longitudinal demand of the HSL450S submarine pipe lines (hardness≤250 HV10, yield strength (450-570 MPa), tensile strength≥535 MPa, elongation≥18%, charpy impact toughness (impact energy: the single≥45 J, the average≥60 J)). Furthermore, the test results of N5 electromagnetism ultrasonic also meet the demand of GB/T9711.3-2005.