Ball Mill High Chrome Grinding Media Chemical Specifications

Release time：2021-10-12

The grinding body of a ball mill  

 

Four, grinding body  

 

(1) Type and material of grinding body  

(1) the type of grinding body  

 

Different shapes and sizes of grinding bodies have different grinding effects in the grinding process.  Ball mill used in cement plant  

According to its shape, there are mainly the following types of grinding body:  

 

1. Steel ball Steel ball is a kind of grinding body widely used in ball mill.  According to the grinding process requirements, usually choose φ20-120mm steel of various specifications  

The ball;  For the ball mill coarse grinding warehouse is generally selected φ50-100mm various steel balls, fine grinding warehouse is selected φ20-50mm various steel balls.  

Steel forging Steel forging is short cylindrical in shape and its specifications are expressed in millimeters of length multiplied by diameter.  Steel forging is generally used in the fine mill bin of an open circuit ball mill,  

Also used for closed - circuit ball mill of fine powder bin.  

 

Commonly used steel forging specifications are φ15mm×20mm,φ18mm×22mm,φ20mm×25mm,φ25mm×30mm and so on.  Small mill mill steel  

Forging diameter is smaller than φ12mm.  

 

3. Steel bar Steel bar is an abrasive body used in rod mills.  Bar specifications are expressed in millimeters of length multiplied by diameter.  Steel rod diameter is generally selected  

φ40-90mm, the rod length should be 50-100mm shorter than the length of the mill rod bin.  For example: φ2.4×13mm wet baseball mill, the effective length of the first chamber is  

2.75m, the specification of steel rod is φ60×2650mm, φ65×2650mm and φ70×2650mm.  

(2) material selection of grinding body  

 

The abrasive body should have high wear resistance and impact resistance.  Require its material hard, wear-resistant and not easy to crack.  Burrs and burrs are not allowed on the surface of the grinding body  

The roundness of cracks and steel balls shall not exceed 2% of their diameter.  

 

In cement industry, the consumption of grinding body and lining plate is quite large. The quality of grinding body material not only affects the grinding efficiency of the mill, but also  

And related to the mill operation rate.  Countries around the world have made achievements in improving the abrasion resistance of abrasives from the 1960s to the 1970s  

Widely used in high chromium cast iron (steel) balls.  Japan mainly has high chromium steel ball, low chromium steel ball and alloy white cast iron ball;  Germany mainly has high chromium cast iron ball  

And low alloy steel ball;  Alloy steel balls commonly used in the United States and Canada.  In recent years, in China's cement industry, the grinding body material used by the ball mill is as follows  

Several:  

 

1. High chromium cast iron high chromium cast iron is a kind of high chromium content of alloy white cast iron, its characteristics are wear resistance, heat resistance, corrosion resistance, and has a considerable toughness.  

The surface hardness of high chromium cast iron ball with Martensite as matrix can reach 54-66 HRC.  The wear resistance of high chromium cast iron ball is 8-12 times that of ordinary carbon steel ball.  

2. Low chromium cast iron low chromium cast iron contains a small amount of chromium, can maintain the white cast iron to obtain martensitic metallography.  Low chromium cast iron has lower toughness than chromium cast iron.  

However, it has good wear resistance and is suitable for use as the lining plate in small ball, iron forging and fine running in.  

 

3. Forged bearing steel Forged bearing steel can be used to manufacture steel balls of various diameters, with carbon content of about 1.0%, chromium content of about 1.5% and other elements  

Conventional content.  The consumption of the ball is higher than that of the high chromium cast iron ball, but because of the low alloying element content, it still has a wider use of the market.  

 

Baseball mill steel rod material requirements of high hardness, wear resistance, constantly broken, not bending, commonly used 40Mn steel or 70 high carbon steel rolled.  

(2) Reasonable loading capacity of grinding body  

(1) Calculation formula of filling rate  

 

The percentage of the filling volume of the grinding body to the effective volume of the mill is called the filling rate of the grinding body.  

 

 

 

Type in the  

-- Grinding grinding body filling rate, %;  

 

V -- Grinding volume of grinding body filling, m;  

s3  

V -- Effective volume of mill (bin), m.  

m3  

(2) The filling rate is calculated by measuring the grinding surface height  

 

.  

When the mill is loaded into the grinding body, it is necessary to verify whether its filling rate is consistent with the value specified in the ball matching scheme, or it is ground during the mill operation  

When some steel balls and steel forging are needed after the wear of the grinding body, the filling amount of the grinding body is calculated by measuring and looking up tables.  The practice is to grind nothing  

In the case of material or only a small amount of material, first measure the effective diameter D of the mill with a ruler;  The center of the mill is then measured from the grinding surface to the top liner  

i  

Then calculate the H/D value, and its relationship is as follows (See Figure 7-11).  

 

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