How to choose the material of the jaw plate of the jaw crusher when crushing high hardness ores

When crushing high hardness ores such as granite, basalt, quartzite, high-grade iron ores, etc., the jaw plate of the jaw crusher bears huge impact loads and severe abrasive wear. Improper material selection can lead to early failure of jaw plates, decreased production efficiency, and a sharp increase in ton costs. Scientific selection of jaw plate materials requires a systematic evaluation of operating conditions, balancing performance, and matching the correct production process.

The following is a professional selection framework based on technical principles and practical experience:

Core selection principle: shifting from "single hardness index" to "comprehensive performance matching"

For high hardness ores, the selection of jaw plate materials should not only pursue high hardness, but also strive for the best balance between toughness, hardness, work hardening ability, and impact energy under working conditions, with the goal of achieving the highest "ton ore wear cost" cost-effectiveness.

Comparison and Selection Guide for Mainstream Material Solutions

Material category, typical brand/process core characteristics, applicable working condition analysis, precautions

1. Improved/ultra-high manganese steel Mn18Cr2 and Mn22Cr2 have high toughness and excellent work hardening ability. Under strong impact, the surface hardness can rapidly harden from around HB200 to HB450-550, forming a wear-resistant surface. One of the preferred options. Suitable for coarse crushing of large and high hardness ores, with sufficient impact load, it can effectively stimulate their work hardening potential. Excellent performance under conditions of large feed particle size and strong jaw swing impact. If the impact is insufficient (such as fine crushing cavity type or excessive fine material after pre screening), the hardening effect will be poor and wear will occur quickly. Dependent on standardized water toughening heat treatment.

2. High manganese steel casting/composite, such as Mn18Cr2 matrix+high chromium cast iron/hard alloy block, achieving a balance of rigidity and flexibility. The high toughness matrix resists impact, and the embedded high hardness alloy blocks provide extreme wear resistance points. A powerful solution for extreme abrasion conditions. Suitable for working conditions with extremely high quartz content, strong abrasion resistance, and equally large impact loads. Can improve wear resistance by more than 50% -100%. The process is complex and the cost is high. The distribution design and bonding quality requirements for embedded blocks are extremely high. We need to purchase from professional manufacturers with strong technical capabilities.

3. A compromise between hardness and toughness in medium alloy steels such as 40CrMnSiMoRe. Obtaining high initial hardness (HRC 40-48) and moderate toughness through alloying and heat treatment. Suitable for working conditions with moderate impact load or coexistence of impact and abrasive wear. For example, in the middle crushing section where the feed particle size is relatively uniform and the ore hardness is high but there is less flaky material. Stable performance without relying on strong impact hardening. The initial hardness is high but the toughness is lower than that of high manganese steel. Under ultra large and strong irregular impacts, there is a possibility of brittle fracture or angular collapse.

4. High chromium cast iron/martensitic cast iron Cr20~26 has extremely high initial hardness (HRC 58-65) and wear resistance, but low toughness. Only applicable to working conditions with minimal impact loads and mainly abrasive wear. In the vast majority of coarse and medium crushing of high hardness ores, it is not recommended to use it as the main material for jaw plates, as it is prone to catastrophic fracture. It can be used as an inlay block for composite jaw plates, or in specific areas of the crusher cavity that are only subjected to compression and have almost no impact.

Scientific selection decision-making process

Condition diagnosis (input conditions):

Physical properties of ore: uniaxial compressive strength, Mohs hardness, abrasion index (such as Ai value), quartz content.

Crushing process parameters: maximum feed particle size, discharge port size (determining crushing ratio), production capacity requirements, and jaw movement characteristics.

Equipment status: Jaw fracture model, crushing chamber design, whether the host is running at full load.

Performance matching (decision matrix):

The impact load is huge (large, irregular)+high hardness → Ultra high manganese steel (such as Mn22Cr2) or embedded casting composite jaw plate is preferred.

Moderate impact load+extremely strong abrasion resistance → Consider using medium alloy steel or high manganese steel with composite technology in key areas.

Low impact load (such as double cavity type)+strong abrasion resistance → It can be evaluated to use high chromium cast iron composite plates for medium alloy steel or specific parts.

Supplier evaluation and verification:

Process capability: Assess its ability in smelting control, heat treatment equipment (such as automatic temperature controlled quenching tanks), and quality inspection (metallographic, flaw detection, hardness gradient detection).

Technical collaboration: Provide detailed working condition information, request suppliers to conduct wear mechanism analysis and provide selection recommendations, preferably with successful cases of similar working conditions.

Cost effectiveness calculation: Compare the "cost per ton of ore" (jaw plate procurement cost/expected processing tonnage) of different schemes, rather than simply comparing unit prices or promised lifespans.

Key Reminders and Best Practices

Differentiated configuration of "one movement and one stillness": Usually, the dynamic jaw plate bears greater impact and bending stress, and should focus more on toughness; The fixed jaw plate is mainly designed to withstand compression and friction, and materials with slightly higher hardness or better wear resistance can be selected. Adopting asymmetric configuration is a common strategy for optimizing cost-effectiveness.

Pay attention to geometric design and coordination: Excellent cavity design can make material distribution more uniform and reduce local excessive wear. Ensure a tight fit between the jaw plate and the body, as well as between the jaw plate and the jaw bed, to prevent additional impact and fracture risks caused by installation gaps.

Trial and data-driven evaluation: For new working conditions or materials, it is recommended to conduct small-scale trials. By measuring the weight changes before and after the cycle, recording the processing tonnage, and analyzing the wear morphology, establish one's own technical and economic database.

Conclusion

When crushing high hardness ores, improved/ultra-high manganese steel (Mn18Cr2/Mn22Cr2) is still the most balanced and reliable benchmark choice in most coarse and medium crushing conditions due to its excellent impact toughness and adaptive hardening ability. For working conditions where the abrasiveness reaches its limit, high manganese steel based casting composite technology is a high-performance solution under current technological conditions. The final decision should be based on a thorough analysis of specific operating conditions and close cooperation with suppliers with deep material engineering capabilities in order to achieve optimal control of production efficiency and operating costs.