Comparison of casting grinding media balls & forged steel balls

Comparison

Cast Grinding Balls

 

Forged Steel Balls

Raw Material

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

Equipment
Investment

 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
 balls.
  D.For forge-rolling process, labor tensity is heavy
                                                                                               Balls quality

A.Hardness

 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.

B.Impact Value

 Cr≥10%， impact value≥3.8J/cm2, compared with forged steel, impact value is lower. Impact value ≥12J/cm2.

C. Appearance

 There will be casting fractures, some of the balls
 will have sand holes		 uniformity

D.Wear rate

 According to statistics, the wear rate of the forgd steel balls is about twice than the casting balls in mines.

E. Broken rate

  ≤0.3% ≤0.1%

Application Area

 Power plant, cement plant, stone factory, mine, metallurgy Mines