典型管线钢预应变条件下强韧性研究进展

Research on Strength and Toughness of Typical Pipeline Steel Under Pre-strain Condition

针对油气管道运行过程中会产生应变,从而对管线钢的使用安全和寿命产生影响等问题,国内外学者根据不同级别管线钢服役环境,开展了管线钢预应变与其微观组织、硬度、强度、疲劳寿命及其断裂韧性等性能研究。通过分析管线钢机械损伤形成的机理表明,输送油气压力波动是产生损伤的主要原因。基于此,提出采用预变性方法来模拟管线钢机械损伤,并研究了相应的机械性能。不同钢级管线钢材料强韧性规律表明,预应变可以诱发位错增值而产生加工硬化现象,从而形成强化过程。采用模拟的方法来研究预应变条件下服役环境中的管线钢可以有效得出材料由于机械损伤所产生的预应变,以及预应变对微观结构所带来的力学响应,从而可以更好地将管线钢的预应变控制在合理的范围内。

In view of the problems that strain may occur during the operation of oil and gas pipelines,affecting the service safety and service life of pipeline steel,domestic and foreign scholars have carried out researches on the pre-strain,microstructure,hardness,strength,fatigue life,and fracture toughness of pipeline steel according to the service environment of different grades pipeline steel.Through analyzing the mechanism of mechanical damage of pipeline steel,it is found that the pressure fluctuation of oil and gas transportation is the main cause of this damage.Based on this,the pre-deformation method is put forward to simulate the mechanical damage of pipeline steel,and the corresponding mechanical properties are studied.According to the law of strength and toughness of pipeline steel of different grades,it is shown that pre-strain can induce dislocation increment and produce work hardening phenomenon,thus forming a strengthening process.The simulation method is used to study the pipeline steel in the service environment under pre-strain condition,and to effectively obtain the per-strain of material due to mechanical damage and the mechanical impact of pre-strain on microstructure,so as to control the pre-strain of pipeline steel within a reasonable range.