连续油管在制管和焊接热循环模拟过程中组织性能的变化  

Changes of Microstructure and Properties of Coiled Tubing during Piping and Welding Thermal Cycle Simulation

作　　者：黄鹏儒 周勇[1] HUANG Pengru;ZHOU Yong(School of Material Science and Engineering,Xi’an Shiyou University,Xi'an 710065,China)

机构地区：[1]西安石油大学材料科学与工程学院,陕西西安710065

出　　处：《热加工工艺》2020年第17期15-18,23,共5页Hot Working Technology

摘　　要：采用热模拟技术模拟连续油管焊接热循环过程。利用金相显微镜、X射线衍射(XRD)、电子背散射衍射(EBSD)、透射电镜(TEM)分析母材和热模拟试样的微观组织特征,并通过显微维氏硬度计、冲击试验机和拉伸试验机测试母材和热模拟试样的力学性能。结果表明,板材制管后,其金相组织和相结构未发生变化,位错密度和亚晶界数目的增加导致硬度上升,屈服强度和抗拉强度也随之升高,但塑韧性大幅下降。随着热模拟峰值温度增加,管材硬度呈先下降后上升的趋势;且在800℃时,亚晶界位错数目明显下降,软化最严重,塑韧性也显著下降,近似于焊接热影响区软化区域,对应于接头中距离焊缝中心7 mm附近的位置,同时此温度下冷却时间越长,性能下降越明显;当峰值温度达到1300℃时,晶粒严重粗大,各项性能相比于原始管材同样趋于恶化。The welding thermal cycle of coiled tubing was simulated by thermal simulation technology.The microstructure characteristics of base metal and thermal simulation samples were analyzed by metallographic microscope,X-ray diffraction(XRD),electron backscatter diffraction(EBSD)and transmission electron microscopy(TEM).And the mechanical properties of the base metal and thermal simulation samples were tested by micro Vickers hardness tester,impact test machine and tensile test machine.The results show that the metallographic structure and phase structure of the sheet don’t change after tube-making.However,the increase of dislocation density and number of subgrain boundaries lead to the increase of hardness,yield strength and tensile strength and the decrease of plasticity and toughness.With the increase of peak temperature of thermal simulation,the hardness of pipe first decreases and then increases.At 800℃,the number of dislocations at subgrain boundaries decreases significantly,the softening is the most serious,and the plasticity and toughness also decreases significantly.It is similar to the softening zone of HAZ,which is near 7 mm from the weld center.At the same time,the longer the cooling time is at 800℃,the more obvious the performance degradation is.When the peak temperature reaches 1300℃,the grain is coarsening seriously and the properties of the pipe are worse than those of the original pipe.

关 键 词：连续油管 热模拟 组织 性能 

分 类 号：TG457.11[金属学及工艺—焊接]