Fracture, wear and corrosion are the three major failure forms of metal materials. For the abrasive wear condition of the crusher liner, the liner will fail in a relatively short time and then be scrapped. Therefore, corrosion failure does not need to be considered. Its failure forms mainly include wear, fracture and deformation failure. Such failure forms pose different challenges to the mechanical properties of lining materials in order to achieve high wear resistance.
(1) Wear failure and hardness requirements
Under the abrasive wear condition of crusher liner, wear is the main failure mode. Due to the strong influence of abrasive and other working conditions, the workpiece material gradually loses and finally fails. Under the condition of abrasive wear, there are two mechanisms of material removal caused by wear: plastic deformation and fracture, as well as the material removal process caused by plastic deformation mechanism, material removal process caused by fracture mechanism, brittle phase spalling, macro spalling, overall deformation and so on.
This failure mode requires the highest hardness of lining material, which is the fundamental reason why ordinary high manganese steel is not wear-resistant under medium and low impact load. Therefore, the liner material is expected to have a high initial hardness, such as > 45.0hrc.
(2) Macroscopic fracture
Fracture is another main failure mode of workpiece. During the operation of the workpiece, the macro fracture is caused by insufficient toughness of its own material, excessive internal stress, too many defects, unreasonable structure or excessive impact of external force. This failure is completed instantly, which is easy to cause disastrous consequences, and its loss is immeasurable.
When designing wear-resistant parts under abrasive wear conditions, this is the first factor to be considered, that is, the wear-resistant workpiece should have sufficient safety to prevent macro fracture. Improving the impact toughness of castings and reducing the crack growth rate will be conducive to fracture resistance. Improving the internal quality of castings and selecting appropriate casting structure are the necessary conditions for fracture resistance. Therefore, the lining material is expected to have qualified impact toughness, such as > 20j / cm2.
(3) Deformation failure
Deformation failure is due to the low yield strength of the workpiece, resulting in serious macro plastic deformation due to external force in the process of use, and the failure due to the change of workpiece shape. Deformation failure is common in wear-resistant workpieces with low yield strength.
For the yield strength of lining materials, in addition to preventing deformation failure, the improvement of yield strength will better accommodate embedded abrasive particles, make them not easy to become crack sources and hinder crack propagation. Therefore, the lining material is expected to have excellent strength, such as tensile strength > 1300mpa and yield strength > 1100mpa.
(4) Other performance requirements
In addition to the above three points, there are also high requirements for the casting performance and hardenability of the lining plate of the cone crusher. In the pouring process, it is necessary to ensure good mold filling, scum and exhaust effects, clear casting outline and low tendency of pores and inclusions; The cooling speed of the casting in the mold cavity is faster. Under the condition of no white mouth, the grain of the casting is refined and the density is improved.
Hardenability of steel refers to the ability of steel to obtain the depth of hardenable layer during quenching after austenitizing. In practical application, hardenability is usually used as an index to measure the microstructure uniformity after quenching. For wear-resistant parts working under abrasive wear conditions, good hardenability is very important to ensure that the overall structure is ideal. Especially for large castings such as lining plate of cone crusher, hardenability is particularly important.
