Abstract: China needs more and more pipes of high steel grade and large diameter thanks to the country’s rapid construction and development of oil and gas pipelines. Correspondingly, there is a demand for large-diameter and thick-wall induction bend. This paper briefs about the production process of X70 steel grade ?1240mm×25.6mm R6D steel pipe. The bend is shaped by means of intermediate frequency heating. The influence of process parameters on shaping and material quality of this specific bend is analyzed, such as materials of mother pipe, heating temperature, pushing speed and temper point. Heating temperature and temper point are controlled under 950-1050°C and 500- 550°C while the width of heating zone is 50-70mm.With the process parameters and key points of production acquired, induction bend is produced according to the process standard, making breakthrough in production of ?1240mm×25.6mm induction bend.

Key words: X70 steel grade, induction bend, material quality, process parameter, large diameter

摘要： 近年来我国油气管道建设发展迅速,管道趋向高钢级、大口径,急需相关配套的大口径、大壁厚规格弯管研究。介绍了X70钢级?1420mm×25.6mm R6D规格钢管的弯制生产工艺,弯曲段采用中频加热方式成型。分析研究了母管材质、加热温度、推制速度、回火温度等工艺参数对该规格弯管成型及材质的影响,加热温度和回火温度应分别控制在950~1050℃和500~550℃,加热带宽度为50~70mm研制中掌握了生产工艺参数和生产控制要点,生产出符合工艺标准的弯管,?1420mm极限规格弯管生产实现了突破。

关键词: X70钢级, 弯管, 材质, 工艺参数, 大口径