EnglishViews: 0 Author: Site Editor Publish Time: 2026-04-10 Origin: Site
In the operation practice of cone crushers, when using high manganese steel material to crush high hardness materials (such as silica and basalt), sometimes there may be a phenomenon of "surface peeling" instead of normal wear failure. In this situation, on-site engineers often face a difficult judgment problem: is this phenomenon caused by the unqualified material itself, or is high manganese steel not suitable for this working condition and needs to be considered for replacement with high chromium cast iron or alloy steel material? In fact, the causes of surface peeling involve multiple factors such as material properties, working conditions, and casting quality, and require comprehensive analysis to draw reliable conclusions.
1、 Wear resistance mechanism and applicable boundary of high manganese steel
High manganese steel (typical composition of Mn 11% -14%, C 1.0% -1.4%) is a wear-resistant material based on austenite, and its wear resistance depends on the "work hardening" mechanism. When subjected to external impact loads, the surface of high manganese steel undergoes plastic deformation, and a large number of high-density deformation twinning crystals appear in the structure. The surface hardness can increase from the initial HB200 to above HB500, thus forming a highly wear-resistant surface layer. At the same time, high manganese steel has good ductility and is suitable for working conditions under strong impact or gravity compression.
However, the work hardening characteristics of high manganese steel have a key prerequisite: sufficient impact energy must be achieved. Research has shown that high manganese steel can fully exert its work hardening ability and minimize wear loss under high impact energy conditions; When the impact energy is insufficient, its wear resistance significantly decreases, and the wear mechanism shifts to fatigue wear mainly caused by multiple plastic transformations of the material.
Silica (with a Mohs hardness of about 7) and basalt (with a Mohs hardness of about 5-7) belong to high hardness materials, but the impact load characteristics during their crushing process are closely related to the material's block size, crushing chamber type, and equipment operating parameters. If the material block size is small, the feeding particle size is uniform, and the crushing chamber is mainly subjected to extrusion and cutting rather than high-energy impact, the impact energy obtained on the surface of high manganese steel may not be sufficient to trigger sufficient work hardening.
2、 Analysis of the Formation Mechanism and Causes of Surface Peeling
1. The essence of peeling mechanism
The formation of surface peeling on high manganese steel has its specific microscopic mechanism. Research has shown that cracks in high manganese steel after abrasive wear form at the boundary between the surface severe plastic deformation zone and the subsurface rheological deformation zone, which can easily lead to delamination wear. Under high impact energy, deep work hardening occurs on the surface of the material, and there is a significant difference in mechanical properties between the hardened layer and the uncured matrix. Under alternating stress, the hardened layer may undergo large-scale peeling.
In addition, the significant increase in surface hardness after work hardening results in a significant decrease in the toughness and plasticity of the steel, which is another intrinsic factor leading to surface peeling. If there are non-metallic inclusions (such as Al ₂ O3, calcium aluminate, etc.) inside the material, the high hardness and dense slip bands generated after work hardening will further reduce the material's fatigue resistance and promote the occurrence of peeling.
2. Dimensions for determining material qualification
The appearance of surface peeling cannot be simply attributed to unqualified materials, but material defects are indeed one of the important factors that induce peeling. The following aspects need to be focused on for investigation:
Chemical composition control: If the manganese content is less than 11%, a stable austenite matrix cannot be formed, and work hardening cannot be triggered after impact, resulting in a sudden drop of wear resistance by more than 50%; If the carbon content is higher than 1.4%, network carbides will precipitate. Although the hardness increases, the brittleness of the matrix increases, and "cracking and peeling" are prone to occur during wear. In addition, the sulfur content should be controlled below 0.03%, and the phosphorus content should be below 0.07%. Otherwise, harmful elements will accumulate at grain boundaries, leading to a decrease in matrix adhesion and easy detachment from the grain boundaries during wear.
Heat treatment process: High manganese steel castings need to undergo water toughening treatment at 1050-1100 ℃ to dissolve the majority of carbides in austenite. If the heat treatment is improper, residual carbides will be distributed along the grain boundaries, which will significantly reduce the impact resistance of the material.
Casting defects: The failure examples of high manganese steel rolling mill bowl walls and crushing walls show that chemical composition deviation, abnormal microstructure, casting defects, etc. are common causes of early failure, which need to be controlled from both quality management and production process specifications.
If it is confirmed through chemical composition testing, metallographic analysis, and hardness testing that the material composition meets the standards (Mn 11% -14%, C 1.0% -1.4%), and the heat treatment structure is normal (no obvious network carbides in the austenitic matrix), surface peeling is more likely to be due to a mismatch between the working conditions and material characteristics, rather than the material itself being unqualified.
3. Basis for determining mismatched working conditions
After excluding material defects, if surface peeling continues to occur, the following working conditions should be considered:
Insufficient impact energy: The material's block size is too small, the crushing ratio is too large, and the feeding is uniform, which leads to the dispersion of impact energy and insufficient surface work hardening of high manganese steel.
The grinding effect of high hardness materials: Silica and basalt have high hardness and sharp edges, which mainly cause cutting wear on the surface of the material. Research has shown that under low stress impact load conditions, the wear resistance of high chromium cast iron is superior to that of high manganese steel, while high manganese steel performs relatively poorly under such conditions.
Materials containing water or corrosive components: In wet grinding or corrosive environments, high manganese steel is in an active dissolved state, with poor corrosion resistance. The interaction between corrosion and wear will accelerate surface peeling.
3、 Applicability analysis of material replacement
When it is confirmed that the main cause of surface peeling is the mismatch between the working conditions and the characteristics of high manganese steel, replacing with high chromium cast iron or alloy steel material is a feasible direction, but it needs to be carefully selected according to specific working conditions.
1. Applicable conditions for high chromium cast iron
The carbides in high chromium cast iron (Cr 18% -25%) are mainly M7C3 type, with a hardness of up to HV1800-2200. Under general abrasive wear conditions, its wear resistance is 2-6 times that of high manganese steel.
However, high chromium cast iron has clear limitations: its toughness is lower than that of high manganese steel, making it suitable for working conditions with high stress, high wear, but low impact loads; Under high impact loads, the work hardening characteristics of high manganese steel significantly improve its wear resistance, and may even exceed that of high chromium cast iron.
Therefore, when crushing high hardness materials such as silica and basalt, if the impact load is indeed small (such as small material block size and large crushing ratio), replacing with high chromium cast iron may be a reasonable choice. If the impact load is large, high chromium cast iron may actually undergo brittle cracking due to insufficient toughness.
2. Practical plan for bimetallic composite materials
In on-site practice, it is often difficult to balance the requirements of high hardness and high toughness with a single material. Bimetallic composite casting is a mature solution: adding high chromium cast iron wear-resistant alloy inserts on the working surface of the rolling bowl wall, the service life of the cone crusher can reach more than 1.5 times that of a single high manganese steel liner. The specific process is to cast high chromium cast iron inserts into the high manganese steel base material at specific intervals and angles. The inserts provide a high hardness wear-resistant surface, while the base material provides sufficient impact toughness.
Another solution is to use a composite structure of tooth plate and tooth liner plate, with the tooth plate made of high chromium cast iron and the tooth liner plate made of high manganese steel, to improve hardness and wear resistance while controlling manufacturing costs.
3. Decision path for material selection
Continue to use high manganese steel for dimension determination and replace it with high chromium cast iron using bimetallic composite
The impact load is relatively large, small, and moderate
The material has a moderate to high hardness
The material is mainly composed of large blocks and small blocks, with a mixed particle size
Not suitable for corrosive environments, more suitable, more suitable
Low cost consideration, medium high
In addition, for working conditions that still wish to retain the advantages of high manganese steel, improved high manganese steel materials such as Mn18Cr2 alloy high manganese steel can be considered. This type of material undergoes composite modification treatment, which can refine grain size and purify grain boundaries. The casting has high hardness, good toughness, impact resistance and wear resistance, and is suitable for the working conditions of large and medium-sized cone crushers.
4、 Comprehensive processing suggestions
When the high manganese steel rolling bowl wall experiences surface peeling when crushing silica or basalt, it is recommended to follow the following steps for treatment:
Material testing: Sampling for chemical composition analysis and metallographic examination to confirm whether the material meets the standards (Mn content, C content, harmful element content, carbide distribution, etc.). This is the key step in distinguishing between "unqualified material" and "mismatched working conditions".
Condition evaluation: Analyze the particle size distribution, crushing ratio, material moisture content, and corrosiveness of the feed, and evaluate whether the actual impact energy level is sufficient to trigger work hardening of high manganese steel.
Classification processing:
If material testing reveals deviations in composition or abnormal organization, the casting process should be traced and qualified high manganese steel rolling mill bowl walls should be replaced, rather than directly changing the material type.
If the material is qualified but the impact energy is insufficient, it is possible to consider adjusting the feeding particle size (increasing the proportion of large blocks appropriately) or using high chromium cast iron/bimetallic composite material.
If the working conditions are stable and the impact load is large, high manganese steel can continue to be used, but attention should be paid to material improvement (such as using high alloy gold grades such as Mn18Cr2).
Process validation: After replacing the material, the wear rate, peeling situation, and equipment operating parameters should be tracked and recorded, and a material selection database that matches the working conditions should be established.
