 |
loading
| Availability: | |
|---|---|
The high-manganese steel jaw plate is a core wear part of jaw crushers, and its quality directly determines crushing efficiency, equipment operating costs, and safety in production stability. As a key component bearing impact loads and material wear, high-manganese steel has become the preferred material for medium and high-hardness material crushing scenarios due to its unique work hardening characteristics. This article systematically breaks down the technical key points and practical specifications of high-manganese steel jaw plates from six dimensions: material properties, full production process, quality inspection standards, packaging, storage and transportation, application fields, and quality identification.
The performance of high-manganese steel jaw plates stems from their special chemical composition and microstructures. Among them, high-manganese steel (ZGMn13) is the mainstream choice in the industry. Its material design centers on "work hardening under impact loads," differing from the static wear resistance logic of ordinary wear-resistant steel.
The composition of high-manganese steel must be strictly controlled, as the proportion of each element directly affects its toughness and hardening ability. The mainstream industry standard followed is GB/T 5680-2019 High-Manganese Steel Castings, with core composition requirements shown in the table below:
Material | Chemical Composition(%) | Mechanical Property | ||||||
| Mn | Cr | C | Si | S | P | Ak/cm | HB | |
| Mn13Cr2 | 12-15 | 1.7-2.2 | 1.15-1.25 | 0.3-0.8 | ≤0.04 | ≤0.06 | >140 | ≤220 |
| Mn18cr2 | 17-19 | 1.8-2.2 | 1.15-1.3 | 0.3-0.8 | ≤0.04 | ≤0.06 | >140 | ≤230 |
| Mn21Cr2 | 21-23 | 1.8-2.2 | 1.1-1.4 | 0.3-0.8 | ≤0.04 | ≤0.06 | >140 | ≤240 |
The performance advantages of high-manganese steel jaw plates focus on "dynamic working condition adaptability." Their static performance (e.g., room-temperature hardness) is not outstanding, but they exhibit unique characteristics under impact loads during crushing operations:
Work Hardening: This is the most core characteristic of high-manganese steel. At room temperature, the hardness of high-manganese steel is only 180-220 HB, but when subjected to impact loads (e.g., material extrusion, impact), the surface austenite structure undergoes rapid plastic deformation, forming a martensite and dislocation strengthening layer. The surface hardness can increase to 500-600 HB, and the more severe the wear, the thicker the hardened layer (usually 2-5 mm), achieving the effect of "becoming more wear-resistant with use."
High Impact Toughness: After solution annealing and water quenching, the impact toughness of high-manganese steel can reach αk ≥ 150 J/cm² (at room temperature), far higher than that of ordinary wear-resistant steel (e.g., αk ≈ 40 J/cm² for NM450). It can withstand severe material impacts without fracture, making it particularly suitable for crushing hard rocks such as granite and iron ore.
Good Ductility: At room temperature, the elongation δ ≥ 20% and the reduction of area ψ ≥ 30%. Even under long-term extrusion, it is not prone to brittle fracture, extending the service life of the jaw plate.
Limitations: The wear resistance of high-manganese steel depends on "impact loads." If the crushed material has low hardness (e.g., limestone) or insufficient impact (e.g., no-load operation), work hardening is difficult to achieve, and the wear rate will increase significantly. In such cases, other wear-resistant materials (e.g., high-chromium cast iron) should be selected.
The quality inspection of high-manganese steel jaw plates covers the "entire life cycle," from raw materials to finished products, and then to transportation and storage. The implementation of standards in each link directly affects the final use effect.
Quality inspection is divided into raw material inspection, in-process inspection, and finished product inspection, with testing items and standards for each link as follows:
Scrap Steel: Phosphorus (≤0.07%) and sulfur (≤0.05%) contents are detected using spectral analysis; the appearance is free of obvious oil and sand.
Ferromanganese: Manganese (≥75%) and phosphorus (≤0.07%) contents are detected, with 3 samples taken per batch and the average value calculated.
Deoxidizer: The silicon content (≥75%) of ferrosilicon and the titanium content (≥25%) of ferrotitanium are detected, and manufacturer quality certificates must be provided.
Melting Stage: One sample is taken from each furnace of molten steel, and the contents of C, Mn, Si, P, and S are detected using a direct-reading spectrometer, with deviations within the standard range; the molten steel temperature (1580-1620 °C) is detected using a thermocouple thermometer.
Casting Stage: One sand mold is randomly sampled per batch to detect moisture content (1.5%-2.0%) and strength (compressive strength ≥ 1.5 MPa); after pouring, the casting appearance is checked for insufficient filling and shrinkage cavities.
Heat Treatment Stage: One sample (of the same material and process as the jaw plate) is taken per furnace to detect the metallographic structure (single-phase austenite with no obvious carbides); hardness (180-220 HB) and impact toughness (αk ≥ 150 J/cm²) are also detected.
High-manganese steel jaw plates are heavy parts (with a single weight usually 50-5000 kg), so packaging must balance rust prevention and anti-collision:
Small Jaw Plates (Single Weight ≤ 500 kg):
Individual Packaging: Wrapped with polyethylene film (thickness ≥ 0.1 mm), with desiccant (silica gel, 50 g per 10 kg of jaw plate) placed inside to prevent moisture intrusion.
Boxing: Placed in wooden packing cases (plywood, thickness ≥ 15 mm), with foam boards (thickness ≥ 50 mm) filled in gaps inside the case to avoid shaking during transportation; "moisture-proof," "upward," and "heavy load" labels are marked on the outside of the case, along with product model, weight, and quantity.
Large Jaw Plates (Single Weight ＞ 500 kg):
No Packaging: Anti-rust paint (thickness ≥ 100 μm) is directly sprayed on the surface, and plastic plugs are inserted into the mounting holes (to prevent foreign objects from entering).
Fixing: Steel pallets (Q235 steel, thickness ≥ 8 mm) are used, and the jaw plates are fixed to the pallets with bolts (M16 or larger bolts, with at least 4 fixing points per jaw plate); stoppers (height ≥ 100 mm) are welded on the edges of the pallets to prevent the jaw plates from slipping.
Key Control Points: Wooden packing cases must meet export standards (e.g., IPPC fumigation, with a fumigation mark affixed); anti-rust grease (e.g., lithium-based grease) must be applied when tightening bolts to prevent rusting and inability to disassemble.
The application of high-manganese steel jaw plates focuses on "matching the hardness and impact load of the crushed material." Its work hardening characteristics determine its irreplaceability in medium and high-hardness, high-impact crushing scenarios. Currently, it is mainly used in four industries: mining, construction, metallurgy, and chemical engineering.
As the "core component" of crushers, the quality of high-manganese steel jaw plates depends on the precise control of material composition, strict implementation of production processes, and full-process quality inspection and management. During selection, it is necessary to comprehensively identify from three aspects: appearance, performance, and manufacturer, combined with scenario factors such as the hardness, temperature, and corrosiveness of the crushed material, to ensure its adaptability and service life.
