Abstract: Currently, China’s main pipeline projects usually use X80 steel grade ?1219mm thick-wall bend. X80 steel grade ?1422mm heat induction bend fills the domestic blank thanks to its high steel grade, large diameter, large wall thickness and complicated manufacturing process. Some technological bottlenecks were solved in development and manufacture of the bend, such as design of chemical components for thick-wall bend and toughness control, while innovating inner and outer simultaneous cooling technology, overall heating induction technology and final tempering heat treatment process to ensure functions of the bend. It is good for toughness and weldability with a long service life. The average yield strength of the bend body exceeds 580MPa and the average tensile strength is 650MPa. The yield ratio is less than 0.90. The average impact toughness of mother material exceeds 150J below -20°C while the average impact toughness of weld seam is higher than 100J below -20°C. The functional quality reaches the world’s advanced level.

Key words: X80 steel grade, pipeline steel, bend, chemical component, bend process, heat treatment

摘要： 目前国内重大管线项目工程基本都采用X80钢级?1219mm大壁厚弯管,X80钢级?1422mm热煨弯管钢级高、口径大、壁厚大、制造工艺复杂,填补了国内空白。研制中解决了厚壁弯管的化学成分设计与强韧性控制技术难题,创新了内外同步冷却技术,通过整体加热煨制技术、最终回火热处理工艺,确保弯管整体性能。弯管强度韧性高、可焊接性好、使用寿命长,管体屈服强度平均超580MPa,抗拉强度平均超650MPa,屈强比小于0.90,-20℃母材冲击韧性平均超150J,-20℃焊缝冲击韧性平均超100J,性能质量达到国际先进水平。

关键词: X80钢级, 管线钢, 弯管, 化学成分, 弯管成型, 热处理