Mineral Sizer Roll Material Selection
Introduce
The Mineral Sizer is mainly used for medium-hard mineral ores’ medium and fine crushing operations. The roller teeth of the Mineral Sizer are subject to the combined effects of material impact, self-weight, etc. during use, and are prone to wear. The wear of the roller teeth not only affects the working efficiency but also poses a threat to the Mineral Sizer itself. During the manufacturing process, the contact surface ratio between the roller teeth and the roller body should reach over 90%, which is a hard fit. Once wear occurs and a gap appears in the fit, the continuous scouring of the materials will cause the wear to further increase, putting the Mineral Sizer in a dangerous state. At the same time, after wear occurs, it will cause the roller body to be injured, the roller teeth to develop cracks, local detachment, the tightening bolts to deform or break, and it will be very difficult to disassemble the roller teeth during the replacement process. Thus, it can be seen that the roller teeth of the crushing roller are the main wear-prone parts and consume a lot of materials.
Therefore, choosing roller teeth with good wear resistance is crucial for improving the working efficiency of the Mineral Sizer. The material should be reasonably selected based on the size of the roller teeth and the properties of the materials to be crushed. This will maximize the performance and potential of various wear-resistant materials and increase their service life, reducing material consumption.
Low Alloy High-Strength Structural Steel Material
Ordinary low alloy high-strength steel is a type of ordinary low alloy steel that contains a small amount of alloy elements (in most cases, the total amount does not exceed 3%), with relatively high strength, good comprehensive performance, and features corrosion resistance, wear resistance, low-temperature resistance, as well as good processing and welding properties.
During the operation of the Mineral Sizer tooth roller, when the surface of the crushing roller’s tooth is subjected to a uniformly distributed pressure of 250 MPa, the maximum stress value is 403 MPa, which is greater than the yield limit value of material Q345 steel. However, this maximum value is located in the small area of the outer circular arc corner of the left end of the tooth slot, considering the actual operation of the crushing roller, the probability of this end being compressed by the material is relatively small, thus the possible state of yielding in this small area can be disregarded. For the majority of the force-bearing tooth slots of the crushing roller, the stress value a is ≤ 300 MPa, which is less than the yield limit value of material Q345 steel, and there is still margin compared to the material, so the material does not undergo plastic deformation. Overall, the stress is smaller in areas with less force, fewer contact surfaces, and smooth transitions in the structure; the stress is greater in areas with greater force and local sharp corners, which is consistent with the actual situation and is credible.
High Manganese Steel Castings
High manganese steel castings are a commonly used casting alloy material for manufacturing Mineral Sizer crushing rollers. Their tensile strength exceeds 600 MPa. In particular, high manganese steel castings such as ZGMn13-2 and ZGMn13-3 have excellent toughness.
High manganese steel castings possess high strength, good plasticity and toughness. Under severe impact or contact stress, their surfaces will rapidly harden while the core remains extremely tough. This combination of hardness on the surface and toughness in the core is extremely advantageous and is beneficial for both wear resistance and impact resistance. Moreover, the more severe the impact on the surface, the more fully the surface hardens and the better the wear resistance becomes. After the surface is worn, the sub-surface is hardened again, thus this performance advantage is widely applied in casting various parts that are resistant to impact and wear.
Cast Carbon Steel Material
For comparison, cast carbon steel ZG230-450, which is used as the manufacturing material for Mineral Sizer, experiences stress values exceeding the yield strength of the material during the roller operation. This does not meet the design requirements, indicating that although ZG230-450 has certain strength and good plasticity, toughness, and machinability, it can only be used in various mechanical parts subjected to relatively small forces and requiring high toughness, and can be used for crushing low-hardness materials such as coal.
Conclusion
The crushing rollers of the Mineral Sizer should be made of different materials depending on the type of the crushed materials. When crushing larger pieces of materials with high hardness and high working stress, high manganese steel or ultra-high manganese steel can be chosen as the roller material; when the crushed materials are smaller or the working stress is lower, alloy steel tooth rollers or cast carbon steel tooth rollers can be selected to increase the service life of the crushing rollers. The crushing rollers are an important component of the Mineral Sizer. To ensure the normal operation of the Mineral Sizer and prevent the cracking of the tooth grooves of the rollers, the strength analysis of the tooth grooves is particularly important.
