THE INFLUENCE OF COILING TEMPERATURE ON THE ANNEALING STRUCTURE AND PROPERTIES OF COLD-ROLLED CONSTRUCTION PRODUCTS
Through the combination of trial production on the production line and laboratory simulation,this paper studies the effect of the coiling temperature on the microstructure and properties of 350 MPa grade structural galvanized products after annealing.The results show that when the coiling temperature is increased from 560 ℃ to 600 ℃,the proportion of second-phase microstructure in hot-rolled base material is reduced by 19.5％,and the performance is reduced by about 20 MPa.The performance transformation trend temperature of the hardened microstructure during annealing is reduced by 20 ℃,which shifts the annealing process window to the left.The cold-coiling steel coil has a higher chilling strength,and the strength reduction gradient is larger as the annealing temperature increases,because the low-temperature coiling steel coil accumulates higher dislocation density and deformation energy,and the recrystallization rate is faster in the early annealing period.With the increase of annealing temperature,the second phase fiber structure gradually disappeared,and the strength and elongation of the steel coil at two coiling temperatures tended to be consistent.Based on the test results,the trial production of the production line shows that increasing the coiling temperature can effectively improve the plate shape of the hot rolling base material,reduce the edge wave shape,reduce the production risk of cold rolling,narrow the distribution range of product properties after annealing,and enhance the stability of performance control.
coiling temperatureannealing processcold rollinglow temperature coilingdislocation densitydeformation energyedge wave shape
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