X90钢直缝埋弧焊管焊接接头的组织和性能  

Microstructure and mechanical properties of X90 steel weld joint of longitudinal submerged arc welded pipe

作　　者：李亮[1] 蔺卫平[1] 梁明华[1] 仝柯 路彩虹[1] 

机构地区：[1]中国石油天然气集团公司石油管工程技术研究院,陕西西安710077

出　　处：《金属热处理》2015年第2期56-60,共5页Heat Treatment of Metals

摘　　要：利用光学显微镜、扫描电镜分析了某厂生产的X90钢管线钢焊接接头的显微组织,通过硬度试验和冲击试验测试了其硬度和韧性变化规律。试验结果显示,其焊缝为针状铁素体和粒状贝氏体组织,熔合区和粗晶区为粗大粒状贝氏体组织,细晶区为多边形铁素体、珠光体和MA组织,混晶区为粒状贝氏体、多边形铁素体、珠光体和MA的混合组织;热影响区有局部硬化和软化现象,且内焊缝硬度高于外焊缝;试验温度高于-20℃时,热影响区的冲击吸收能量和剪切断面率高于焊缝,低于-40^-20℃区间某个值后,冲击性能将降低至焊缝性能以下;热影响区的韧脆转变温度约在-50℃附近,而焊缝的韧脆转变温度约在-70℃附近。Microstructure of X90 pipeline steel weld joint was investigated by using optical microscope and scanning electron microscope. Its mechanical properties were determined by Vickers hardness test and Charpy impact test. The results show that the microstructure of weld seam is acicular ferrite（AF） and granular bainite（GB） ; the fusion zone and coarse grain and heat affect zone（CGHAZ） is coarse GB; the fine gain and heat affect one（FGHAZ） is polygonal ferrite（PF）, P and MA; the mixed grain zone is GB, PF, P and MA. Partly softening and hardening obviously occurs in the HAZ; besides, the hardness of the inside weld is higher than that of the outside weht. The impact absorbed energy and percent shear fracture of HAZ are higher than those of the weld seam when the test temperature is above - 20 ℃, but they soon drops off under those of the weld seam when the test temperature is below a certain point in the range of - 40- - 20 ℃. The ductile-btittle transition temperature of HAZ and weld seam are around -50 ℃ and -70 ℃, respectively.

关 键 词：X90管线钢 焊接接头 热影响区 显微组织 力学性能 

分 类 号：TG142.12[一般工业技术—材料科学与工程]