摘要
为了确保管道在极端环境下长期运行而不产生塑性断裂,选取了A、B两种高FRT(终轧温度)和CST(冷却停止温度)板材进行试验研究。试验结果表明,当温度在-20℃以下时,加载10%预应变会对板材夏比冲击功产生负作用,且A1、B1两种试验板材冲击功高于其他试验板材,B1的韧性优于A1,但两种试验板材在经轧制后其冲击功又可达到同一水平。对A、B两种试验板材采用预疲劳和开缺口进行了-20℃温度下落锤试验,由总能量和J积分值检测结果可见,两种类型试样的剪切面积均能保持在90%以上,可见,工业用厚壁钢板显示出了很好的韧性。微观组织结构研究表明,10%的预应变将会导致材料内部碳氮颗粒和非金属夹杂物附近形成空隙,由此而对材料的韧性造成影响,同时,其他因素也可能会引起板材预应变后冲击功的下降,比如在EBSD(电子背散射衍射)方法观察到的材料内部高取向差的区域,其在经预应变后冲击功将会出现明显的下降。
In order to ensure the long term operation of pipeline in extreme environment without producing plastic fracture, A sheet with final rolling temperature(FRT) and B sheet with cooling stop temperature(CST) were chose for experimental investigation. The results showed that below-20 ℃, loading 10% pre-strain would produce negative effects on sheet charpy impact, the impact energy of A1 test sheet and B1 test sheet were higher than that of other test sheets, the toughness of B1 test sheet was better than that of A1 test sheet, but the impact energy of them could reach the same level after rolling. A sheet and B sheet with pre-fatigue and notching were used for drop-weight test at-20 ℃, from the total energy and J integral value, the shear area of the two types of specimens remained above 90%. This proved the industrial thick wall steel plate showed good toughness.The research of microstructure indicated that 10% pre-strain would cause the gap near the non-metallic inclusions and particles of carbon and nitrogen in materials, which would affect the toughness of the material, other factors might also cause the decrease of the impact energy, as observed the material internal high misorientation region with the EBSD method, its impact energy after pre-strain would be significantly decreased.
出处
《焊管》
2018年第3期63-68,共6页
Welded Pipe and Tube
