Complete Product Characteristics and Advantages of High Manganese Steel Liners (ZGMn13 / ZGMn13Cr2 / ZG120Mn13Cr2)
Austenitic high-manganese steel (Hardfield steel), featuring a hard outer shell and a tough core; the more it is subjected to impact, the more wear-resistant it becomes. It is the mainstream wear-resistant casting material for mining, cement coarse grinding and crushing equipment.
I. Core Material Characteristics
1. Unique work-hardening effect (key characteristic) Following qualified water-hardening treatment, the original matrix hardness is only HB 180–230, with excellent toughness; when subjected to repeated impact and compression from steel balls and ore, the surface austenite undergoes deformation hardening, rapidly increasing the surface hardness to HB 450 600, forming a hard, wear-resistant surface layer; as the hardened layer wears away, the new surface layer continues to be re-hardened by impact, creating a ‘self-regenerating wear-resistant layer’ effect.
The inner matrix layer consistently maintains high toughness and does not become brittle as a whole, achieving a combination of external hardness and internal toughness.
2. Ultra-high impact toughness, resistance to fracture and spalling:
With high impact toughness and resistance to impact and compression, it is unlikely to crack, fracture or spall when subjected to violent impacts from large chunks of ore or large steel balls; compared to high-chromium cast iron, the risk of fracture under severe impact conditions is significantly reduced, making it suitable for areas of equipment subject to high impact loads.
3. ZGMn13Cr2: Chromium-modified enhancement (industry standard) – 1.5–2.5 per cent chromium added to the standard Mn13 base:
Refines grain size, suppresses the precipitation of brittle carbides and reduces the tendency for castings to crack
Accelerates work hardening, improving initial wear resistance by 30–50 per cent
Improves resistance to rust and adaptability to mildly corrosive wet grinding conditions
Resists plastic deformation; the probability of lining plate bulging or deformation is significantly lower than that of standard ZGMn13.
ZG120Mn13Cr2: With a slightly higher carbon content and greater hardening potential, it is suitable for lining plates in semi-autogenous mills and heavy-duty mills subject to high impact loads.
4. Water-hardening heat treatment ensures performance.
After heating to 1050–1100°C and sufficient holding time, rapid water quenching dissolves brittle carbides at grain boundaries into the austenite, resulting in a single-phase austenitic microstructure; high-manganese steel that has not undergone proper water-hardening is highly brittle and extremely prone to cracking and scrapping, whilst components that have undergone qualified water-hardening fully realise their plasticity, toughness and hardenability.
II. Comprehensive Product Advantages
1. Excellent overall service life under high-impact conditions: In high-impact environments such as coarse grinding chambers, semi-autogenous mills and crushers, service life is increased several-fold compared to ordinary carbon steel and low-alloy steel; significant advantages are evident when processing large chunks of hard rock (granite, basalt, iron ore), reducing frequent component failure.
2. Impact and fracture resistance ensure high equipment safety. Complete fragmentation of the component is extremely rare, preventing large castings from falling into the equipment’s interior after fracture and causing secondary accidents such as machine jamming or gear damage, thereby reducing the risk of unplanned downtime.
3. Suitable for wet grinding and damp mining environments. The austenitic microstructure offers superior resistance to rust and mild corrosion from slurry compared to alloy steel, and is less prone to rusting and flaking in damp slurry conditions.
4. High resistance to plastic extrusion (Cr-modified version). The chromium-alloyed version effectively resists bulging and extrusion deformation of the liners under heavy impact, maintaining its structural integrity during long-term service and preventing bolt holes from tearing.
Reduces the frequency of downtime caused by liner breakage, thereby minimising downtime losses;
Reduces the frequency of spare part consumption, lowering labour costs for disassembly and reassembly;
Enhances protection of the mill shell, indirectly safeguarding the shell structure and extending the service life of the main unit.
III. Objective Limitations (Must be clearly understood when selecting a model)
1. Sufficient impact energy is required to realise the wear-resistant properties. In fine grinding compartments, with small steel balls and fine powder, where conditions involve pure frictional abrasion, the impact is insufficient to form a hardened layer, resulting in rapid wear. This application is not recommended; high-chromium cast iron should be prioritised.
2. Not suitable for prolonged exposure to temperatures exceeding 250°C. At high temperatures, brittle carbides may re-precipitate, reducing toughness and increasing the likelihood of cracking and failure.
3. Welding or surfacing repairs are not permitted, as the heat from welding will cause carbide precipitation, making the area around the weld highly susceptible to cracking.
4. The yield strength is not particularly high; plastic deformation may still occur under extreme, excessive compressive loads. For heavy-duty applications, ultra-high-manganese Mn18Cr2 is the preferred choice.
IV. Typical Applicable Operating Conditions
Recommended applications:
Lining plates for coarse grinding chambers in ball mills, feed end lining plates and lift bars
Lining plates and grate plates for SAG (Semi-Autogenous) mills
Jaw plates for jaw crushers, and bowl liners/crushing walls for cone crushers
Protective plates for large silos and chutes, and areas subject to impact from large ore chunks
