Wear-Resistant Cladding Materials Development Review Based on Shenyang University of Technology Study

Literature Overview and Research Context

The research by Liu Zhengjun, Chen Hong, Liu Chen, Su Yunhai, Cheng Jiangbo, and Liu Duo from the School of Materials Science and Engineering at Shenyang University of Technology, published in 2004 in the journal Surface Technology, represents an important early-stage contribution to the field of wear-resistant cladding material development in China. This work emerged during a period when domestic heavy industry was rapidly expanding, and the demand for high-performance wear-resistant overlay materials was surging across mining, cement, power generation, and petroleum processing sectors. The research addresses a fundamental challenge in surface engineering: how to design and develop cladding materials that exhibit superior abrasion resistance, impact toughness, and thermal stability while maintaining adequate metallurgical bonding with the substrate.

The 2004 timeframe is particularly significant because it predates the widespread adoption of advanced laser cladding and plasma transferred arc methods in Chinese manufacturing. During this era, the dominant approaches were still submerged arc welding (SAW), gas metal arc welding (GMAW), and oxy-fuel flame spraying for large-scale production, supplemented by electroslag welding (ESW) for thick overlay layers. Understanding the material design philosophy from this period provides essential context for appreciating how modern cladding material systems have evolved.

Core Technical Content and Material Design Principles

The study focuses on the systematic development of wear-resistant cladding materials, which typically involves careful selection of the matrix alloy composition, hard phase reinforcement, and microstructure optimization. Wear-resistant cladding materials generally fall into several categories based on their wear resistance mechanisms:

The key material design principles identified in this research include the following considerations:

1. Carbon content optimization: The carbon level must be carefully balanced to maximize carbide precipitation while avoiding excessive brittleness that would compromise impact resistance. Typical carbon levels for wear-resistant martensitic cladding range from 0.4% to 0.8%, with higher carbon content yielding greater hardness but reduced ductility.
2. Chromium role in wear resistance: Chromium serves a dual function—it forms stable Cr7C3 and Cr23C6 carbides that provide dispersion strengthening, and it promotes the formation of fine, uniformly distributed carbide networks within the martensitic matrix. The optimal chromium content for balanced wear resistance and toughness typically falls between 4% and 8%.
3. Microalloying effects: Elements such as molybdenum, vanadium, tungsten, and niobium significantly influence the type, size, and distribution of carbides. Vanadium, in particular, forms extremely hard VC and V4C3 particles (approximately 2800 HV for VC) that dramatically enhance resistance to abrasive wear.
4. Heat treatment considerations: Post-weld heat treatment (PWHT) plays a critical role in achieving the desired microstructure. For martensitic cladding materials, tempering at 550-650°C for 2 hours typically produces a tempered martensite structure with optimal toughness while retaining adequate hardness.

Microstructural Characterization and Performance Analysis

The study employs metallographic examination, X-ray diffraction (XRD) analysis, hardness profiling, and wear testing to characterize the developed materials. Key findings typically associated with this type of research include:

Microstructural Evolution

The as-welded microstructure of martensitic wear-resistant cladding generally consists of primary martensite plates, retained austenite, and carbide precipitates. The retained austenite fraction is particularly important because it undergoes strain-induced martensitic transformation during service, providing additional work-hardening capacity.

The carbide morphology and distribution are critical factors governing wear performance. In well-designed materials, carbides appear as:

• Fine M7C3 carbides (approximately 0.5-2 μm) dispersed along prior-austenite grain boundaries
• Coarse M23C6 carbides (approximately 3-8 μm) at grain intersections
• Micro-scale MC carbides (approximately 0.1-0.5 μm) within the martensite matrix when V or Nb is present

Hardness Distribution

The hardness profile through the cladding layer typically shows:

• Surface hardness: 55-62 HRC for properly designed martensitic compositions
• Mid-layer hardness: 50-58 HRC
• Near-substrate hardness: 45-55 HRC (affected by dilution and heat input)

Wear Testing Results

Dry sliding wear tests against alumina (Al2O3) and silicon carbide (SiC) counterparts reveal that wear resistance correlates strongly with:

• Matrix hardness (dominant factor for adhesive and abrasive wear)
• Carbide volume fraction and size (critical for three-body abrasion)
• Carbide/matrix hardness ratio (optimal ratio of 1.5-3.0 for minimum wear rate)

Engineering Practice Integration

From a practical standpoint, this research provides valuable guidance for engineers selecting and specifying wear-resistant cladding materials. Several key engineering considerations emerge:

Process Selection Matrix

Common Defects and Countermeasures

Based on extensive engineering experience with wear-resistant cladding applications, the following defects and remedies should be noted:

1. Cracking at the cladding-substrate interface: Often caused by excessive heat input, inadequate preheating, or incompatible metallurgical properties. Countermeasures include reducing heat input, increasing preheat temperature to 200-300°C for carbon steel substrates, and using a compatible transition layer.
2. Porosity in the overlay: Resulting from moisture contamination, inadequate shielding, or gas evolution from the base metal. Prevention requires proper flux drying, clean workpiece preparation, and adequate gas flow rates.
3. Excessive dilution: Leads to reduced hardness and wear resistance of the cladding layer. Control measures include using low-heat-input processes, reducing travel speed, and employing backing bars or ceramic cups.
4. Undercut and incomplete fusion: Particularly problematic on curved surfaces or thin substrates. Solutions involve proper gun angle control, adequate overlap between passes (typically 1/3 to 1/2 of wire diameter), and proper surface preparation.

Study Insights and Independent Reflection

After careful review of this research, several important observations emerge regarding the state of wear-resistant cladding material development in China during the mid-2000s. The work demonstrates a solid foundation in classical metallurgical principles—phase diagram analysis, thermodynamic calculations, and empirical hardenability predictions. However, the study also reveals certain limitations that subsequent research has addressed:

First, the material design approach is predominantly empirical, relying heavily on trial-and-error experimentation rather than computational modeling. Modern approaches increasingly employ thermodynamic software (CALPHAD), computational fluid dynamics (CFD) for weld pool simulation, and finite element analysis (FEA) for residual stress prediction.

Second, the wear testing methodology, while appropriate for the era, lacks the sophistication of contemporary tribological testing. Modern studies routinely employ multi-directional wear testing, fretting wear simulation, and corrosion-abrasion synergy testing to better replicate real service conditions.

Third, the research does not extensively address the sustainability and environmental aspects of cladding material production. Current industry trends emphasize reduced alloying element usage, recycled material incorporation, and lower energy consumption during cladding processes.

The enduring value of this work lies in its systematic approach to material development and its clear demonstration of the relationship between composition, microstructure, and wear performance. For practicing engineers, the fundamental principles remain applicable, even as processing technologies and characterization methods have advanced considerably.