The Effect Of High Temperature Deformation On Microstructure And Performance Of Grinding Ball Steel

High-carbon low-alloy steel used in the manufacture of large diameter grinding ball has the characteristics of high hardness, good wear resistance, but toughness and crush resistance is poor. This research focus on the effect of high temperature deformation on the microstructure and properties of high carbon low alloy steel, obtain the fine grains and higher toughness by controlling the recrystallization process. The results of deformation temperature test show that: When the deformation amount is 25%, deforming at 900 ℃have no recrystallization phenomenon, but deforming at 1000℃, the grain degree increased to 9 grade, and the recrystallization grain degree decreases with the deformation temperature increase. The results of forging the steel at 1050 ℃,with the deformation amount are 0, 25%, 50% and 75%, show that: when the deformation amount within the range of 50%, the size of recrystallized grain is decreased with the deformation amount increasing, the grain degree increased to 10 grade. But when the deformation amount exceeds 50%, the increase of deformation amount can not made the grain for further refinement, but repeat deformation have a significantly effect on grain refinement.The steel forging at 1000℃ with the deformation amount is 50%, place in the 900℃holding furnace immediately, insulation 0s ~ 180 s before quenching, results show that: the smallest grain size appear at the holding time is 10 s, the grain degree is 10.5 grade, after that, grain quickly grow with the holding time extended, but the grow speed slow down.The grain degree decreased to 9 grade at the holding time is 120 s. Research the effect of deformation mode on microstructure and properties, the results show that: the impact number of the forging process have no obvious effect on grain refinement as the total deformation amount is same,Improve the production process of B2 steel Φ120mm diameter grinding ball. Change the size of raw steel bar from Φ85 ? 160 mm to Φ80 ? 180 mm, make the forging temperature between 1000 ℃ ~1050 ℃ by controlling the heating conditions, using wind-colling equipment for reducing the steel ball pre-cooling time to 60 ~ 80 s. The grinding ball that producted by the improved production process, have a good surface hardness and hardenability thickness, the whole ball toughness and anti-broken also have improved. The falling-broken number increased form 1800 to 2500, which have a goodpractical significance.