For vertical shaft impact breaking, whether it is “stone hitting stone” or “stone hitting iron”, the movement and force conditions of the material in the rotor are the same: the material enters from the center of the rotor, and passes through the distribution plate, guide plate, throwing head, etc. Throw it into the crushing cavity. That is to say, these parts in the rotor are in direct contact with the material and are easy to wear, so their wear resistance is directly related to the replacement cost and operating efficiency. In order to improve the wear resistance, the material of the wear-resistant parts must be selected first.
Wear-resistant material series
The series of wear-resistant materials currently in common use in my country are:
(1) High manganese steel series: such as high manganese steel (ZGMn13), high manganese alloy (ZGMn13Cr2MoRe), super high manganese alloy (ZGMn18Cr2MoRe), etc.;
(2) Anti-wear high chromium cast iron series: such as high, medium and low chromium alloy cast iron (such as Cr15MoZnCu);
(3) Wear-resistant alloy steel series: such as medium, low and high carbon multi-element alloys (such as ZG40SiMnCrMo and ZG35Cr2MoNiRe);
(4) Ao Bei Ductile Iron (ADI) series;
(5) Various composite or gradient materials and cemented carbide materials: such as chromium carbide composite materials (Cr2C3+Q235), high-energy ion implantation tungsten carbide materials (WCSP), high toughness cemented carbide (YK25.6), etc.;
(6) Various non-metallic wear-resistant materials: such as polymer ceramic composite materials, silicon nitride (Si3N4), toughened zirconia (Y203+ZrO2), toughened aluminum oxide (Al2O3/ZrO2), etc.
Below we take the sand making machine as an example to introduce the material selection of the material distribution plate, the throwing head, the guide plate and the anvil in the core part of the rotor.
1. Distribution tray
When the material enters the high-speed rotating rotor and contacts with the distribution plate, it rotates with the rotor. Under the action of centrifugal force, it moves from the center of the distribution plate (rotor) to the outer end of the channel (throwing port).
In this process, the distribution plate bears the vertical impact load and the horizontal stone acceleration load at the same time, and the outer edge of the distribution plate wears more severely than the center part. Therefore, the material of the distribution tray must have a certain degree of toughness to overcome vertical impact; it must have a certain degree of hardness and be able to withstand horizontal loads.
In summary, the distribution tray should be selected from medium and low-carbon multi-element alloy steels (such as ZG40SiMnCrMo and ZG35Cr2MoNiRe).
2. Throwing head
The movement of the stone in the rotor: the horizontal speed of the stone when it enters the contact point of the distribution plate is zero, and it rapidly accelerates the horizontal movement in the direction of the throwing head (outer edge of the rotor). The speed of the stone at the throwing head can be determined according to kinematics, as shown in the figure below.
The throwing head has to withstand strong impact and high-speed punching (sliding friction). Therefore, the material of the throwing head should be selected from high-manganese alloy steel series wear-resistant materials (such as ZGMn13Cr2MoRe), or ultra-high manganese alloy steel (such as ZGMn18Cr2MoRe).
When the high manganese alloy steel is subjected to severe impact, the surface hardens rapidly, while the core still maintains extremely strong toughness. The outer hard and inner toughness are both wear-resistant and impact-resistant. The heavier the surface is impacted, the more the surface hardens and the wear-resistant The better the performance.
3. Guide plate
In the crushing process, the guide plate mainly bears the gravity and sliding friction of the stone. Therefore, the wear of the guide plate is mainly high-speed scouring. Optional wear-resistant chromium cast iron series materials (such as Cr15MoZnCu).
4. Iron drill
In the vertical shaft impact crusher of the “stone hitting iron” type, the abrasion of the iron drill is very high. In order to obtain higher kinetic energy conversion, the facing surface of the iron drill is installed on the front of the material. The material hits the iron drill close to the vertical, and the iron drill bears severe impact load.
According to the characteristics of wear-resistant materials, the hardness of high manganese steel (such as ZGMn13) is higher than HB550 when subjected to severe impact, while the core hardness is lower than HB170-230, and still maintains extremely strong toughness. Therefore, high manganese steel is an ideal material for iron drills.
The wear parts of the vertical shaft impact crusher (except the iron drill) are small in size, small in size, and light in weight. In order to reduce production costs, some parts suppliers often use the same material distribution plate, guide plate, and ejector head body. A kind of wear-resistant material casting, blind pursuit of hardness, the effect is not ideal, resulting in a substantial increase in cost and waste, users should pay more attention when purchasing accessories.