Effect of Annealing on Texture and Fracture Separation of Rolled X80 Pipeline Steel

The tension,impact and drop welght tesring (DWT) tests were perfomed on X80 pipeline steel for the 2nd west-east gas pipeline project.Obvious fracture separation was found on the fracture surface of the sample.The fracture separation reason was investigated by using electron backscatter diffraction(EBSD) technique to analyze the transformation of microstructure and textures of the pipeline steel before and after annealing.The results show that there were obvious textures of 111 〈110〉 and 110 〈001〉 in hot rolled X80 steel plate,but a reduction of the two textures and a new texture of 110 〈111〉 was found after annealing at 700℃ for 2 h.The average grain size of the pipeline steel changed from 2.27 μm to 2.84 μm,and the fracture separation was reduced or even eliminated after annealing.