Influence of ICCGHAZ on the Low-Temperature Toughness in HAZ of Heavy-Wall X80 Pipeline Steel

Metals

Chao Fu¹  Haichuan Li²  Xueda Li³  Yong Wang³  Tao Han³  Bin Han³ 

[1] College of New Energy, China University of Petroleum (East China), Qingdao 266580, China;PipeChina West East Gas Pipeline Company, Shanghai 200122, China;School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China;

关键词: pipeline steel;    low-temperature toughness;    ICCGHAZ;    LBZ;    Arctic regions;   

DOI  :  10.3390/met12060907

来源: DOAJ

【 摘 要 】

Low-temperature embrittlement in the heat-affected zone (HAZ) of heavy-wall X80 weld joints is a primary challenge for arctic oil & gas exploitation. In this paper, the influence of intercritically reheated coarse-grained HAZ (ICCGHAZ) on the low-temperature toughness of the weld joint in a 22 mm thick X80 spiral submerged arc welded pipe was studied through instrumented Charpy V-notch impact test at −80~20 °C and corresponding fracture surface characterization. The results indicated that the influence of ICCGHAZ on the overall toughness of the weld joint is related to temperature. At temperatures below −45 °C, individual and tiny martensite-austenite (MA) constituent debonding can trigger cleavage fracture–which was proved to be nucleation-controlled–and the probability of embrittlement of the ICCGHAZ increases. At temperatures higher than −45 °C, only relatively large or closely distributed MA constituent in ICCGHAZ satisfies the conditions to trigger propagation-controlled cleavage fractures, and the influence of ICCGHAZ on the overall toughness is not remarkable.

【 授权许可】

Unknown