The dual challenges of wear parts in crushing equipment: Analysis and response to gouging wear and impact fatigue mechanisms

In mining crushing operations, the failure of wear-resistant components in equipment is a core factor affecting production continuity and cost control. Among them, gouging wear and impact fatigue, as two primary and often intertwined failure mechanisms, pose severe challenges to the lifespan of key components such as jaw plates, hammer heads, and cone crushers. A deep understanding of the interaction between these two mechanisms is fundamental for selecting suitable materials, optimizing component design, and formulating maintenance strategies.

1. Gouging wear: Micro-cutting and plastic deformation under high stress

Gouging wear is a form of high-stress abrasive wear that primarily occurs under conditions where there is intense compression and sliding between the material and the surface of wear-resistant components, such as in the crushing chamber of a jaw crusher and the parallel zone of a cone crusher.

1. Mechanism and manifestation:

When hard and sharp mineral materials (such as quartz and granite) are scratched across the metal surface under immense pressure, their effect goes far beyond simple "scratching". At this point, the abrasive particles act like miniature cutting tools, generating extremely high stress at the contact point that exceeds the material's yield limit, leading to plastic flow or direct microscopic cutting of the metal surface. Macroscopically, this manifests as varying depths of furrows or gouges on the component surface. As the process is repeated, material is continuously removed, the working profile changes, and this directly leads to a decrease in crushing efficiency and loss of control over product particle size.

2. Key influencing factors:

Material characteristics: The hardness, sharpness of edges and corners, and particle size of the material are external factors. When the hardness of the material approaches or exceeds the hardness of the metal surface, wear intensifies rapidly.

Material hardness and toughness: The macro-hardness and microstructural hardness of wear-resistant materials are the primary defense against gouging. However, solely pursuing high hardness may lead to brittleness issues, thus it needs to be balanced with sufficient toughness to prevent large-scale spalling of the material under cutting action.

II. Impact fatigue: crack initiation and propagation under cyclic loading

Impact fatigue arises from the high-frequency, high-energy repetitive impact loads sustained by equipment during operation, which is particularly prominent in components such as the plate hammer of an impact crusher and the hammer head of a hammer crusher.

1. Mechanism and manifestation:

Every material impact is a dynamic loading process, generating alternating stress on the surface and subsurface of the component. Even if a single impact does not cause immediate fracture, the cumulative stress cycles can lead to the initiation of microcracks at material defects such as carbide boundaries and inclusions. These cracks gradually propagate and connect under subsequent impacts, ultimately resulting in material failure in the form of spalling, chipping, or fracture. This type of failure often occurs suddenly, and the external appearance of the component may not change significantly before failure, but the internal damage is already severe.

2. Key influencing factors:

Impact energy and frequency: The magnitude of impact kinetic energy and the number of impacts per second determine the stress level and accumulation rate.

Material toughness: The impact toughness and fracture toughness of a material are the inherent keys that determine its ability to resist crack initiation and delay crack propagation. Materials with insufficient toughness often have a shorter fatigue life.

Residual stress: The beneficial surface compressive stress generated by manufacturing processes (such as casting and heat treatment) can partially offset the working tensile stress, thereby extending fatigue life.

III. Intertwined Mechanisms and Synergistic Effects: The Destruction of 1+1>2

In actual working conditions, gouging wear and impact fatigue rarely occur in isolation, but rather promote each other, forming synergistic damage:

Wear promotes fatigue: The grooves and pits generated by gouging wear become stress concentration points, significantly reducing the fatigue strength of the area and accelerating the initiation of fatigue cracks.

Fatigue exacerbates wear: Microscopic cracks and surface spalling caused by impact fatigue disrupt the integrity of the material surface, exposing fresh, unhardened metal layers, thereby making them more susceptible to subsequent gouging wear.

Contradiction in material performance requirements: high hardness is required to resist gouging wear, while high toughness is needed to resist impact fatigue. This presents seemingly contradictory comprehensive requirements for material design and selection.

IV. Coping Strategies: Systematic Thinking Based on Mechanisms

To address this dual challenge, we need to adopt a systematic approach rather than seeking a single "solution":

1. Selection and development of material applicability:

The choice is made based on the primary and secondary relationships between the two mechanisms in specific equipment. For example, in jaw crushing conditions dominated by intense squeezing, high manganese steel materials can be selected, which can produce significant surface work hardening under intense impact stress, thereby simultaneously improving the resistance to gouging wear. For impact breaker hammers dominated by high kinetic energy impacts, high toughness alloy steel or high toughness high chromium cast iron may be required to ensure resistance to fatigue cracking on the basis of sufficient hardness. Bimetallic composite casting technology (such as casting high-hardness alloys at the striking end and using high-toughness materials for the handle) is an effective zoning solution.

2. Optimization of structural design:

By simulating the distribution of working stress through finite element analysis (FEA), the geometry of components can be optimized to avoid abnormal stress concentration. For instance, the contour of the hammer head can be optimized to reduce impact stress, or the position of the lining plate bolt holes can be designed appropriately to minimize the risk of fracture.

3. Refinement in use and maintenance:

Uniform feeding: Avoid direct impact from one side or oversized materials, and maintain a relatively stable load.

Regular flipping and swapping: For example, the jaw plate is regularly turned around for use, which homogenizes the wear areas and extends the overall lifespan.

Condition monitoring: Establish a regular inspection system, focusing on early signs of cracks and deformation, to achieve predictive replacement and prevent catastrophic fracture accidents.

Conclusion

Gouging wear and impact fatigue are two sides of the same coin in the failure of wear-resistant components in crushing equipment. Their destructive forces are not simply additive, but rather produce a synergistic amplification effect through complex interactions. Therefore, there is no universal single method for their long-term control. Instead, it requires a deep understanding of specific working conditions and failure modes. Through the systematic integration of materials science, mechanical design, and production maintenance, a balance point between hardness and toughness suitable for specific scenarios can be found, thereby achieving coordination between equipment reliability, production efficiency, and operating costs.