Comparison of casting grinding media balls & forged steel balls
Cast Grinding Balls
Forged Steel Balls
|A.Main part is the steel scrap,low cost, low price fluctuation,
easy to get
|A.The main material is round steel; the steel factory produces the raw material; the price is subject to fluctuations in the raw material market; and the acquisition route is single.
|B.The raw materials are flexible, according to the customer’s requirements, only in the melting part, replacing the ratio of the raw material composition; convenient for stock picking; low capital pressure
|B.The raw material is not fixed. According to the customer’s requirements, it is necessary to customize the round steel of different sizes to the steel mill; heavy pressure on stocking founds.
|C.Raw material ingredients can be self-controlled to
ensure product quality
|C.Raw material composition is controlled by steel factories
|A.Automatic casting production line can produce grinding balls from dia30 to 150mm balls and some cylpebs with different composition;only need to change the metal moulds and pattern
|A. Forges steel balls, size bellow 80mm, can adopt hot rolling process; above d80mm, need to adopt forge-rolling process.
|B.Heat treatment machine, separating machine can be used to
process all type of the balls and cylpebs
|B.For different size of the balls, need to change different equipment, including round steel heating machine and water quenching machine.
|C.Medium frequency induction furnace can be used with other
castings to maximize equipment resources
|C.Tempering machine can be used to process all types of the steel
|D.For forge-rolling process, labor tensity is heavy
|After heat treatment, the surface HRC can reach to HRC≥58， HRC difference between the inner and surfacewithin 2degrees (Cr≥10%)，Wear rate is low, Uniform hardness without deformation，the output is stable.
|After heat treatment, the surface hardness can reach HRC≥56, but due to using the residual heat for water quenching, the hardenability is poor, and the hardened layer is only ≤15 degrees. Therefore, for large balls, the hardness difference between inside and outside is lbig, after entering the ball mill, after 12-13mm wear , the hardness decreases rapidly, the overall wear increases, which will lead to the loss of roundness and affect the output of the ore platform.
|Cr≥10%， impact value≥3.8J/cm2, compared with forged steel, impact value is lower.
|Impact value ≥12J/cm2.
|There will be casting fractures, some of the balls
will have sand holes
|According to statistics, the wear rate of the forgd steel balls is about twice than the casting balls in mines.
E. Broken rate
|Power plant, cement plant, stone factory, mine, metallurgy