Study On Deformation And Microstructure Of The Titanate-slag Furnace Shell

Furnace shell often in high temperature, high pressure, corrosive environments with a work event of an accident, the consequences could be disastrous. Therefore, to ensure the safe use of smelting equipment, have to take full account of the furnace shell deformation behavior in the service process. Domestic research materials more macro-mechanical direction on fatigue process, but rarely its research from microscopic fields. In fact, the microstructure evolution and the final microstructure of the material produced in the deformation process will determine the mechanical properties of the product from nature.The issues of Q235 steel to the study.Taking into account the mechanical properties of metallic materials affected by temperature, combined with the actual working environment of the furnace shell, in this paper, the experimental research that is launched from the microstructure and mechanical damage of materials in both directions. By using OM、TEM、SEM and EDS analysis of electronic equipment for various operating conditions change parts of the furnace shell microstructure;By using LITM5305 type tensile tester of the furnace shell parts of the mechanical condition of each performance, and by high-cycle fatigue test to obtain the S-N curve of Q235 steel;Through the use of SEM observed fatigue fracture, ultimately discussed the effects of environmental temperature on Q235 steel furnace shell fatigue fracture mechanism.These results show that with the enhancement of the working temperature:furnace shell show that substantially strength decreased, ductility increasing. However,in the range of 150 ~ 300 ℃, due to the "blue brittle" effect will cause the plastic periodically reduced; By polygonal ferrite grains become flat or elongated shape,grain boundaries become more blurred.And from the iron mouth and slag mouth parts of the furnace shell withstand high temperatures, the emergence of ferrite- pearlite banded structure. Also formed a squarish certain number of second-phase particles,these phenomena have increased the density of cracks sources, greater damage to toughness of the substrate; Slightly increases the amount of pearlite, pearlite lamellar spacing is significantly increased, the dislocation density is reduced, resulting in reduced strength of the substrate; S-N curve drawing, measured fatigue limit of the observed mouth is 180 MPa, the fatigue limit of the iron mouth is 170MPa; Iron mouth is prone to cyclic creep and the content of Al2O3 increased significantly, these phenomena are increasing the probability of the occurrence of fatigue fracture of the lead here.