Product plan

With the continuous development of the field of metallic materials, we have developed a new type of metallic material that not only has high wear resistance but also can be mechanically processed. The bimetallic composite ball mill uses a metal material with good toughness as the base material. On this technology, a high-alloy material with high hardness and high wear resistance is compounded, making the liner of the composite ball mill have bimetallic properties, that is, the high hardness and high wear resistance of the working layer and the high toughness of the base layer.

Product advantages

The lining plate as a whole has uniform hardness, composition and structure.

2. It has a relatively high impact fatigue durability and can resist impacts of a certain intensity.

3. It has a relatively low wear rate, does not deform or show obvious wear during use.

Mechanical properties

Impact toughness, flexural strength and Rockwell hardness

After quenching heat treatment, compared with the single high-chromium cast iron material, the mechanical performance parameters of the bimetallic composite material samples have been significantly improved, and they can fully meet the service conditions where the grinding balls and abrasives in the ball mill apply impact loads to them.

2. Interface hardness distribution

Seven sampling points were randomly selected on both sides of the transition area of the sample interface, and the load was set at 1.96 Newtons. The microhardness (HV) was measured using a microhardness tester. Figure 1 shows that the microhardness of the high-chromium cast iron side in the transition zone is significantly higher than that of the carbon steel side, but the hardness value presents a smooth transition state. The two materials form a certain width of bonding zone, and the interface composite quality is relatively high.

Usage effect

The installation test of high-chromium cast iron/carbon steel bimetallic liners was carried out on the No. 4 wet ball mill in the beneficiation workshop of Jinshandian Iron Mine, a subsidiary of a certain steel mining industry. The inner dimensions of the mill chamber were 3600mmx6000mm, and the ore production capacity was 160 tons per hour.

When the bimetallic composite liner and the original alloy steel liner are simultaneously installed in the ball mill, during the operation of the wet mill, in the corrosive slurry environment, the liner will be subjected to the impact and abrasion of the materials and grinding balls, resulting in various forms of frictional losses of the liner. In order to ensure that the two types of liners are subjected to uniform and equal impact and wear loads during the operation of the ball mill as much as possible, the two types of liners are arranged at intervals in the dimensional direction in this sample.

Comparison of wear resistance of liners

The weight loss data of the liner wear shows that under the full-load service conditions in the wet ball mill, the relative wear resistance coefficient of the high-chromium cast iron/carbon steel bimetallic liner is three times that of the original alloy steel liner. The difference in wear resistance can be explained as follows: The original alloy steel liner obtained a material structure with a single high-hardness martensite as the matrix after quenching. The microstructure obtained after air-cooling quenching heat treatment of high-chromium cast iron is as follows: The matrix structure is high-hardness martensite, on which ultra-high-hardness eutectic carbides MC are uniformly distributed. Therefore, the latter is more suitable for the extreme wear-resistant service environment in terms of material structure, and its service life is also significantly longer than that of the former.

Worn surface

Due to the impact of the grinding balls, the surface of the liner undergoes plastic deformation along the load direction and presents a flat and uniform fracture mode. In addition, the high-strength and hard ferrochrome carbides limit the deformation area of the material, making the martensitic phase a weak link and the main area for material failure.

When the worn surface is further magnified, there are many tiny holes distributed on the surface of the liner. The main reason for this phenomenon is that the wet ball mill is a corrosive wear environment. After the base structure is corroded, even if the carbides are extremely hard, the base structure has no adhesion foundation. Under the alternating load of the grinding balls and abrasives, it will cause peeling and shedding. This is a very important reason for the relatively short service life of the inner lining plate of the wet ball mill. By using the bimetallic liquid lost foam composite casting method, high-chromium cast iron/carbon steel bimetallic lining plates were successfully trial-produced and successfully applied to the 3.6-meter iron ore wet ball mill, completing a nine-month full-condition test. In the service environment of wet ball mills, bimetallic liners possess the high strength and high toughness of eutectic high-chromium cast iron, as well as the high toughness and high ductility of ferrous steel. The weight loss results show that the relative wear resistance coefficient of bimetallic liners is three times that of the original alloy steel liners