The Research On Behavior Of Oil Tank Steel Particles Back To The Matrix And Precipitation

Basing on the oil tank steel as the research object, the experiments with continuous cooling transformation and different process parameters on the second phase precipitation behavior effect were conducted in University of Science and Technology Beijing Gleeble-1500 thermal simulation machine, and then by optical microscope and transmission electron microscopic analysis technology microstructure of steel are observed and studied. Finally, using TEM chip and extraction complex type technology,second phase are observed. The main contents and results are as follows:1,According to observing the different heating temperature and different holding time, we can see: With increasing of heating temperature, grain of austenite grew up continuously, second phase particles precipitate with less; With the increase of the holding time, grain of austenite grew, second phase particles continue to grow.2,By analyzing experimental data of continuous cooling transformation, and combining with the microstructure observation, the experimental steel continuous cooling transformation curve ( CCT ) were got. Through the comparison of single and double pass continuous cooling transformation curve we could found: single pass has earlier phase transition than double pass. 3,By means of observe the metallographic organization, we could found: with the increase of deformation, the pearlite percentage decreased gradually, bainite content increased gradually; with the increase of the holding time, ferrite is more uniform and pearlite gradually increased; as the finishing rolling temperature decreases, the ferrite grain size is smaller; with the final cooling temperature reduce, ferrite grain shape is smaller, and less clear boundaries.4,By means of TEM extraction replica technique to study t second phase particle precipitation of different rolling process parameters, the results showed: with the increase of deformation and final rolling temperature decreases, the second-phase particle volume fraction increases gradually; and the holding time and cooling temperature had little influence on precipitate.