The Research Of X100 Pipeline Steel Hot Deformation Behavior And The Continuous Cooling Transformation

With the larger development of national economy, the demand for oil and gas is more and more large. In 2014 China and Russia signed the 365 million tons of oil import contracts, the same year in December, the Xin Jiang kelamayi found a large oil and gas field whose reserves is 1 billion tons.Thus,the pipeline has the huge market potential,under this big background.The improvement of pipeline steel level can reduce the cost of construction, therefore, the research for high grade pipeline steel has a practical significance. In this paper, the X100 pipeline steel is chosen as the research object, the recrystallization behavior of hot rolling process and deformation in the process of continuous cooling transformation process are studied, the main content of the paper is as follows:(1)The stress-strain curve of experimental steel is drawn by using single channel compression experiment.The influence of the deformation temperature, deformation rate on X100 pipeline steel after hot deformation of austenite dynamic recrystallization is studied.The results show that the recrystallization occurs more easily in high temperature, low speed and exceeding the critical variables. The parameter Z of experimental steel is calculated based on single channel compress ion experiment data.The result is as follows: 484.05exp()8.31 Z T=e(2)The experimental steel deformation resistance model is established by mathematical software for linear regression, according to the experimental data of single channel time 0.423 0.348 0.390180 exp( 1.579 2.251)() [1.648() 0.648()]10 0.4 0.4TTe e es-= - + - The correlation coefficient is 0.947, ha ing a good fitting.(3)The experiment of the steel with no deformation is carried out on hot simulation experiment machine. According to the experiment data the CC T curve of steel is messured.In the cooling rate of 2-5 ℃ / s, the microstructure at room temperature are mainly polygonal ferrite, a small amount of acicular ferrite and granular bainite,when the deformation temperature reaches 8 ℃ / s,the polygonal ferrite turns into a polygon ferrite acicular ferrite, and exists in the form of quasi polygonal ferrite, the amount of granular bainite is gradually increased,then when the cooling speed is 30 ℃ / s, ferrite transformation end, room temperature organizatio nare acicular ferrite and granular bainite. With the increase of cooling rate, grain size has been further elaboration.