What Are The Common Causes of Lining Plate Rupture And Failure?

The rupture failure of the lining plate (rolling bowl wall and crushing wall) of the cone crusher is one of the main problems affecting the normal operation of the equipment and production costs. The lining plate is subjected to high-frequency and alternating impact loads during operation, and its stress state is complex. Its fracture is often the result of multiple factors working together. This article is based on on-site practice and fault cases, systematically sorting out the common causes of lining plate rupture and failure.

1、 Material and casting defects

1. Improper control of chemical composition

The lining material is usually made of high manganese steel, and its chemical composition directly affects the mechanical properties and wear resistance of the material. When the chemical composition is not controlled properly, it will significantly increase the risk of lining plate rupture:

Excessive sulfur content: Sulfur increases the thermal brittleness of castings, causing a decrease in material strength at high temperatures and an increase in solidification shrinkage rate. Sulfur and manganese preferentially combine to form manganese sulfide, which is discharged in the form of slag, resulting in a decrease in the effective manganese content of castings.

Excessive phosphorus content: Phosphorus increases the cold brittleness of castings, making the strength of the material at low temperatures less than the sum of thermal stress and shrinkage stress generated by the castings, which can easily lead to cold cracks.

Insufficient manganese content: When the manganese content is too low, the wear resistance of the casting significantly decreases, while also reducing the material's work hardening ability.

2. Defects in casting process

The internal defects generated during the casting process are potential causes of early cracking of the lining plate:

Shrinkage and porosity: There is a large difference in wall thickness at the hot junction of the rolling mill wall casting, and the cooling speed varies. If the riser design is unreasonable or the pouring system is not conducive to shrinkage, shrinkage and porosity are easily formed inside. These defects become stress concentration points when subjected to impact loads, which can easily cause crack propagation.

Grain boundary carbides: In the as cast microstructure of high manganese steel, if not cooled properly, a large amount of carbides will form and be distributed in blocks on the grain boundaries, seriously reducing the strength of the grain boundaries.

Insufficient concession: When the concession of sand molds and sand cores is poor, the shrinkage of castings is hindered, resulting in significant shrinkage stress and leading to hot cracks.

Residual internal stress: The residual internal stress of metal castings is often the "deadly killer" of lining plates. Due to the working conditions of the cone crusher, the surface of the lining plate must withstand high radial compression force and circumferential shear force. The residual internal stress of the lining plate will quickly lead to premature cracking and scrapping.

2、 Improper installation and fastening

1. The lining board has not been leveled and adjusted

When installing the lining plate, if it is not leveled and adjusted, it will be biased towards one side, which will result in uneven load distribution around the lining plate when it is broken. Under the continuous impact load, the side subjected to greater force is prone to fatigue cracking and propagation, ultimately leading to fracture failure.

2. The mating surface is not cleaned thoroughly

If there are rust layers, debris, or burrs on the contact surface between the moving cone and the moving cone lining plate, and they are not cleaned thoroughly, it will result in a loose fit between the lining plate and the cone. When there is a gap between the mating surfaces, the lining plate will experience relative displacement and micro motion wear during the crushing process, leading to fatigue cracks under alternating stress.

3. Insufficient fastening strength

The locking bolt is not tightened in place: When the tightening strength of the locking bolt is insufficient, the lining plate is prone to loosen during the crushing process, and the impact load borne by the loosened lining plate is more severe, accelerating the rupture.

Poor welding of the compression cutting ring: Poor welding between the compression cutting ring and the lining plate, or wear and tear of the weld seam during operation, can cause the lining plate to lose effective fixation, resulting in displacement and impact under crushing force, and ultimately rupture.

The pre tightening force does not meet the requirements: there is no testing tool for the pre tightening force between the dynamic cone head and the spindle thread. Maintenance personnel operate based on experience. When the pre tightening force is insufficient, the cone head loosens after the equipment is loaded, causing the lining plate to loosen and wear.

3、 Poor operating conditions

1. Iron impact

Overloading is one of the important causes of lining plate rupture. When metal objects such as iron blocks enter the crushing chamber:

The iron block has a high hardness and cannot be broken, causing rigid collisions between the lining plates. The instantaneous impact load far exceeds the rated load of the lining plates

Repeatedly passing iron can cause fatigue damage to the cone and lining plate

When larger iron cannot be discharged at once, it will be squeezed multiple times with the crushing chamber, and even cause the crusher to get stuck

The iron marks on the dynamic cone liner and the fixed cone liner are common evidence on site. After multiple iron passes, the fatigue accumulation of the liner eventually leads to fracture failure.

2. Improper feeding method

Poor feeding can cause significant pressure fluctuations during the operation of the crusher and frequent impacts on the lining plate

Feed eccentricity: The material cannot be evenly distributed around the crushing chamber, causing the cone to experience force eccentricity and the local lining plate to bear excessive load

There are many large pieces of material: the feed particle size exceeds the design allowable value, causing concentrated impact in the upper part of the crushing chamber

Uneven feeding particle size: When large pieces of material enter, the cone descends, and small pieces of material immediately descend, changing the force point from multi-directional balanced force to unidirectional local force

3. The nature of the incoming material does not meet the requirements

When the material hardness is too high (such as high hardness ores with f=12-16), the crushing load borne by the lining plate increases significantly. If operated under conditions beyond the design capacity for a long time, the lining plate is prone to premature rupture due to fatigue.

4. Poor contact on the supporting surface

The dynamic cone is supported on the spherical bearing shell of the spherical bearing seat. When the spherical bearing shell is worn or has quality problems, it will cause the dynamic cone to move downwards, and the supporting contact surface cannot make good contact, resulting in increased friction between the dynamic cone and deteriorating the stress state of the lining plate, increasing the risk of rupture.

4、 Maintenance and management oversight

1. Insufficient maintenance time for fillers

When there are no spare spindles and shelves on site, every time the lining plate is replaced, the filling material is put into use before reaching sufficient strength, and the crushing force directly acts on the cone and lining plate, which can easily cause cracks in the lining plate.

2. Lack of regular inspections

During the operation, the welding seams, bolt tightening, and wear status of the lining plate were not regularly inspected, which resulted in the inability to detect potential hazards such as looseness and welding failure in a timely manner, leading to minor problems evolving into lining plate rupture and failure.

3. Failure of iron removal equipment

The permanent magnet iron remover has poor iron removal effect or lacks protective devices such as metal detectors, resulting in frequent occurrence of iron overload and long-term overload impact on the lining plate.

5、 Combination of comprehensive factors

In actual production, the rupture of lining plates is often the result of multiple factors working together. For example, the case of a certain beneficiation plant: the hardness of the ore is high (f=12-16), there is a lot of dust on site, the supervision of the belt operator is not in place, the iron removal effect of the permanent magnet iron remover is not good, and the iron passing is frequent; In addition, there are defects during the installation of the dynamic cone liner plate, such as loose fit, unstable welding of the cutting ring, inadequate tightening of the locking screws, and improper installation of the liner plate, which make the dynamic cone liner plate prone to rupture and failure during use.

This case demonstrates that a single factor may not be sufficient to immediately cause lining plate rupture, but when multiple adverse factors are combined, the failure rate of the lining plate will significantly accelerate.

Classification and summary of reasons for lining plate rupture and failure

The specific factors of the reason category mainly manifest as

Material and casting defects, improper chemical composition, casting process defects such as shrinkage and porosity, grain boundary carbides, and residual internal stress

Improper installation and fastening without leveling or straightening, unclean mating surfaces, insufficient fastening, uneven load distribution, loose lining plates, and increased impact

Operating conditions are harsh, including iron impact, improper feeding, overload impact due to hard feeding, local stress, and fatigue damage

Lack of maintenance and management oversight, insufficient filling time, inadequate inspection, premature bearing due to iron removal failure, unresolved hidden dangers, and frequent iron passing