During testing pipe and steel for 2nd china west-east gas pipeline (WEGP), fracture separation was found in X80 line pipe steel plates in tensile tests, charpy impact tests and DWTT tests. In this paper, fracture separation is investigated by using EBSD technique to analyze microstructure and to compare it with microstructure of the material after annealing. Results show that there are obvious texture of {111} <110> and {110} <001> in hot rolling plate, but a reduction of this two textures and a new texture of {110} <111> are found after annealing at 700°C for 2 hours. It is found in charpy impact tests that the {111} <110> micro-texture, as a main factor leading to fracture separation was eliminated in annealed specimens. The average grain size of specimen changed from 2.2687μm to 2.8362μm comparing with hot rolling plate because of the decomposition of Bainite. The results of Orientation Imaging displayed that the proportion of substructure and the distribution of misorientation of grain boundary of annealed specimens did not changed remarkably in contrast to the original ones. It is concluded that, X80 steel has well heat stability.

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