Semi Autogenous Mill Special Development Of Steel For Grinding Ball

In order to adapt to the dressing with large semi autogenous mill has been the trend of rapid development and the condition of the large size grinding ball market demand increases, the subject to semi autogenous mill with 120 mm in diameter and wear resistant steel ball steel for research and development goals, the chemical composition and the Jominy hardness distribution and grinding ball hardness distribution between the relational model, according to the depth of hardening identified scope of the chemical constituents of the ball mill. Design and smelting with Cr, Mn, Si, V alloy elements mainly eight kinds of test steel, forging, and a 120 mm diameter steel ball test, tests on different chemical composition of experimental steel forging grinding ball quenching penetration depth, after heat treatment, the microstructure, mec hanical properties and fracture resistance were studied.120mm in diameter of grinding ball by quenching after forging process, water quenching temperature control in 35℃±3℃, into the water temperature for 810℃-840℃, water time 140 s, effluent after air coo ling, using residual heat quenching tempering. Grinding ball are martensite, which 6#,7#,8# three grinding ball quenching depth high, the surface hardness reach more than or equal to 60 HRC and hardness in the heart to is more than or equal to 40 HRC, impac t toughness equal to or larger than 70 j, falling ball test > 3000 times, after comparison of comprehensive performance, to 7#, 8# test of steel production of grinding ball has both high hardness, but also has high impact toughness, showed good fracture resistance, suitable for the production of semi self mill special ball.The 1#-4# four grinding ball and 5#-8# four grinding ball contrast can be seen, grinding ball components add V element in grinding ball plays a role in grain refinement, second phase strengthening, grinding ball hardness and wear resistance increased, and with good toughness and good anti cracking performance.According to the test results, taking the test 7# grinding ball component as a benchmark, in Laiwu steel using converter LFVD continuous casting, rolling ratio is greater than 15, 500 tons of steel production, steel in Connaught Hebei steel forging grinding ball, in Taiyuan iron ore Yuanjiacun 3 sets of semi self mill(phi 10.36 * 5.49 m, 5500 kW, 2000 tons / hour) use, the iron ore Yua njiacun statistics, grinding ball consumption reduction for a ton of ore consumption about 700 grams of grinding ball, achieve development goals.