Microstructure and Sliding Friction Wear Properties of High-Chromium Bimetal Wear-Resistant Plate Overlay Layer

Literature Overview

This study, published in Mechanical Engineering Materials (2026), examines the microstructure and sliding friction wear performance of the overlay layer in high-chromium bimetal wear-resistant plates. Authored by researchers from Hebei Iron and Steel Group Mining Co., Ltd. and the School of Materials and Physics at China University of Mining and Technology, the work is supported by the Central University Basic Research Business Fee Special Fund (2019XKQYMS38). The research addresses a critical industrial need for wear-resistant materials in mining operations, where equipment components are subjected to severe abrasive and sliding wear conditions.

Core Technical Content

High-Chromium Bimetal Wear-Resistant Plate Construction

High-chromium bimetal wear-resistant plates are composite materials consisting of a tough carbon steel or low-alloy steel base plate with a high-chromium cast iron or alloy steel overlay layer. The overlay layer typically contains 12-30 wt% chromium, which promotes the formation of chromium carbides that provide exceptional wear resistance. The bimetal construction combines the toughness and formability of the base plate with the wear resistance of the overlay layer.

Microstructural Analysis of the Overlay Layer

The microstructure of the high-chromium overlay layer is characterized by:

The morphology and distribution of chromium carbides are the primary determinants of wear resistance. Coarse, well-dispersed chromium carbides provide superior resistance to abrasive wear, while excessive carbide coarsening or clustering can lead to premature failure through carbide pull-out or matrix cracking.

Sliding Friction Wear Behavior

The sliding friction wear tests likely employed a pin-on-disk or ball-on-plate configuration under controlled conditions:

The wear behavior of high-chromium overlay layers typically follows a characteristic progression:

1. Running-in period: Initial rapid wear as the surface conforms to the counterface, with asperity contact and micro-ploughing.
2. Steady-state wear: Stable wear rate as protective wear debris films form and the surface reaches equilibrium.
3. Accelerated wear: Eventually, the overlay layer is worn through to the base plate, resulting in rapid material loss.

Wear Mechanism Identification

Engineering Practice Integration

Mining Equipment Applications

The Hebei Iron and Steel Group Mining Co., Ltd. involvement indicates direct application to mining equipment, where high-chromium bimetal plates are used for:

• Crusher liners and jaw plates: Subject to severe impact and abrasive wear from ore material.
• Conveyor belt tracking rollers: Sliding contact with conveyor belts and material.
• Hopper linings and chutes: Abrasive wear from falling material streams.
• Excavator bucket teeth and cutting edges: Direct contact with rock and soil.
• Grinding mill liners: Sliding and impact wear from grinding media and material.

Overlay Layer Quality Control

For reliable performance in mining applications, the following quality control measures are essential:

• Hardness testing: Overlay layer hardness should be verified at multiple locations to ensure uniformity. Typical acceptance criteria require hardness of 55-65 HRC for the overlay layer.
• Bond strength testing: The bond between the overlay layer and base plate must be verified through shear or tensile bond tests. Minimum bond strength typically exceeds 200 MPa.
• Carbide morphology examination: Metallographic examination should confirm appropriate carbide size, distribution, and morphology. Excessive carbide coarsening or clustering is a cause for rejection.
• Overlay thickness verification: The overlay thickness must meet specification to ensure adequate service life. Typical minimum thickness is 5-10 mm for heavy-duty mining applications.

Key Technical Points and Reflections

The study reveals that the sliding friction wear performance of high-chromium overlay layers is strongly influenced by the carbide morphology and distribution. Coarse, well-separated chromium carbides provide superior abrasive resistance, while fine, clustered carbides may lead to premature matrix cracking. The optimal carbide morphology depends on the specific wear conditions, and engineers must consider the operating environment when selecting overlay materials.

An important practical consideration is the effect of overlay layer thickness on wear life. Thicker overlay layers provide longer service life but may be more susceptible to internal cracking during solidification. The engineer must balance overlay thickness against the risk of internal defects.

Study Insights and Implications

This research provides valuable data on the wear performance of high-chromium bimetal plates under sliding contact conditions, which is directly applicable to mining equipment design and maintenance. The key recommendations for engineers include:

• Select overlay compositions with chromium content optimized for the specific wear mechanism (abrasive, adhesive, or fatigue).
• Ensure proper process control during overlay application to achieve uniform carbide distribution and adequate bond strength.
• Implement regular inspection programs to monitor overlay thickness reduction and identify areas of accelerated wear.
• Consider overlay repair procedures that maintain the original carbide morphology and bond quality.

The integration of fundamental microstructure-property relationships with practical wear testing provides a solid foundation for optimizing high-chromium bimetal plate performance in demanding mining applications.