Common challenge: Accurate matching of material hardness and selection of wear-resistant accessories for mining crushing

In mining crushing and grinding operations, premature failure of wear-resistant components can often be traced back to a common root cause: a systematic mismatch between the wear-resistant characteristics of the component materials and the physical (especially hardness) and working condition mechanical properties of the processed materials. This mismatch is not a simple "soft grinding hard" or "hard hitting hard" problem, but a complex system engineering involving materials science, tribology, and equipment dynamics. One of the core challenges in controlling equipment operating costs and ensuring production stability is to achieve precise matching between the two.

1、 Typical manifestations and consequences of mismatches

The mismatch between material selection and material hardness usually leads to two main abnormal failure modes:

The failure of "using softness to overcome hardness" type: When the hardness of the wear-resistant material is significantly lower than that of the material, it is mainly manifested as rapid micro cutting wear. Sharp material particles easily plow through metal surfaces, forming deep grooves and causing rapid loss of accessory size. For example, using ordinary high carbon steel lining plates to treat granite with high quartz content may have a lifespan only a fraction of that of the compatible material.

Brittle hard bearing failure: When excessive pursuit of material hardness is made to resist hard materials, sacrificing necessary toughness, it is easy to cause brittle fracture or peeling. Under high impact or high stress extrusion conditions, materials are unable to absorb energy through plastic deformation, resulting in the initiation and rapid propagation of cracks, leading to the collapse of large blocks. For example, using a high hardness but low toughness ordinary high chromium cast iron plate hammer on the impact of large materials may result in early fracture.

Both of these failures result in a significantly shorter effective lifespan of the components than expected, leading to decreased production efficiency, increased maintenance costs, and safety hazards.

2、 The core influence of material hardness: a systematic consideration beyond a single parameter

The material hardness (commonly measured by Mohs hardness or Shore hardness) is the primary reference for material selection, but it is not the only basis. Its impact needs to be evaluated from a system perspective:

Relative hardness ratio: The ratio of the macroscopic hardness (such as Rockwell hardness HRC) of wear-resistant materials to the material hardness is crucial. Generally speaking, in order to achieve effective resistance to abrasive wear, the material hardness should reach 0.8 times or more of the material hardness. For quartz (Mohs hardness 7), the hardness of wear-resistant parts needs to reach HRC 56 or above to have basic resistance ability.

Material form and particle size: Hard and sharp particles (such as fresh broken sections) are more destructive than round and blunt particles. Large block materials mainly bring high impact, while fine particle materials tend to cause high stress grinding.

Working condition stress type: The same hard material produces different mechanical effects in different equipment:

High stress impact (such as counterattack fracture, hammer fracture): The material is required to have toughness as the main factor and both hardness. Lack of resilience is a fatal weakness.

High stress compression (such as cone fracture, jaw fracture parallel zone): requires materials to have high crushing strength and fatigue resistance.

Low stress scratches (such as conveyor chutes): The importance of material hardness is more prominent.

3、 Performance spectra and adaptation principles of wear-resistant materials

No material can perform well under all working conditions. The mainstream wear-resistant materials form a spectrum from "high toughness" to "high hardness", and material selection is to find the suitable points on this spectrum.

Core characteristics of material categories (balance between hardness and toughness) Typical adaptation Material hardness and working conditions Main risks and unsuitable scenarios

High manganese steel has high toughness and high work hardening potential. The initial hardness is low, and the surface can harden to HBW 500 or above under strong impact. Suitable for high impact and high stress working conditions, crushing medium to high hardness materials such as granite and basalt. It is a commonly used choice for the jaw plate of large jaw crushers and the lining plate of cone crushers. Under conditions of insufficient impact force, it cannot fully harden and its wear resistance cannot be exerted, and it is inferior to ordinary steel.

High chromium cast iron has high hardness (HRC 58-65) and outstanding wear resistance, but its toughness is relatively limited. Suitable for medium or low impact working conditions of high hardness and high abrasive materials, such as vertical grinding rollers, plate hammers (when the impact is moderate), and slurry pump flow-through components. Macroscopic brittle fracture is prone to occur under high-energy impact. High rigidity requirements for installation and support.

The combination of hardness and toughness of medium low alloy wear-resistant steel can be adjusted within a wide range through alloying and heat treatment. Wide adaptability range, customizable according to specific material hardness and impact force. Commonly used in working conditions that combine impact and wear, such as excavator bucket teeth and some hammer heads. If the heat treatment process is not properly controlled, there will be significant fluctuations in performance.

Composite materials (such as bimetallic) combine high hardness materials (such as high chromium cast iron) with high toughness matrices (such as alloy steel) to achieve "wear resistance of the working surface and fracture resistance of the body". Suitable for working conditions with high material hardness and significant impact, such as hammer heads of hammer crushers and tips of impact breaking hammers. The manufacturing process is complex and the cost is high, and the quality of composite interface bonding is the key.

4、 Systematic method for achieving precise matching

To solve this common problem, it is necessary to establish a systematic decision-making process from analysis to verification:

Operating condition audit and failure analysis:

Clarify core parameters: accurately measure or obtain material hardness, particle size distribution, abrasion index (such as AI value), and moisture content.

Analyze equipment mechanics: Determine whether the main failure mechanism is impact, compression, or cutting, and evaluate the impact energy level.

Conduct historical failure analysis: Conduct macroscopic and microscopic observations on existing failed components to determine whether wear, fracture, or peeling is dominant, providing direct basis for material selection.

Preliminary screening and balancing based on rules:

Establish rules: for example, "High impact+hard materials → prioritize high toughness materials (such as ultra-high manganese steel) and evaluate their hardening potential"; High hardness materials+medium low impact → High hardness materials (such as high chromium cast iron) can be considered, but their toughness needs to be verified to meet safety requirements.

Balancing performance: quantitatively comparing between hardness and toughness, and between initial cost and service life. Introduce 'ton material wear cost' as a comprehensive measurement indicator.

Small scale validation and iterative optimization:

Before a comprehensive replacement, conduct individual or small batch trials and establish strict wear monitoring records (measurement cycle, weight loss, wear morphology).

Compare trial data with expectations and analyze whether they match. This is a necessary trial and error process to reduce technical risks.

Establish a Total Cost of Ownership (TCO) model throughout the entire lifecycle:

Include the purchase price of accessories, the cost of labor and downtime required for replacement, and the associated losses caused by failure (such as damage to other components) in the calculation.

Materials with higher prices and applicability often have lower lifecycle costs than low-priced but unsuitable materials that are frequently replaced.