2013•Cailiao rechuli xuebaoRequires access
Effect of heating temperature on microstructure and properties of X100 grade pipeline steel for heat-bending bend
Gao Hui-lin
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Abstract
Effect of heating temperature on microstructure,strength and toughness of X100 grade pipeline steel was studied by means of mechanical property tests and microstructure observation using OM,SEM and TEM.The results show that strength increases and toughness decreases for the X100 grade steel with the increasing of heating temperature.The microstructure of experimental steel heated at 950-1050 ℃ mainly consists of bainitic ferrite and granular bainite.A good combination of strength and toughness can be obtained for the steel heated at 950-1050 ℃ because of the microstructure of fine bainitic ferrite and granular bainite with multidirectional ferrite lath bundles and high dislocation density.The bainitic ferrite grains of experimental steel grow up obviously when the heating temperature is above 1050 ℃ so that the toughness decreases significantly.Polygonal ferrite appears when the heating temperature is lower than 950 ℃,leading to the decrease of strength of the experimental steel.