Application Status and Development Prospects of Wear-Resistant Cladding Materials in the Cement Industry

Literature Overview

Published in 2009 in the journal China Surface Engineering, this review by researchers from Zhengzhou Mechanical Research Institute provides a comprehensive survey of wear-resistant overlay welding materials and their application in cement industry equipment. The cement industry is characterized by extremely abrasive operating environments where equipment components are subjected to continuous contact with cement clinker, raw meal, and fly ash particles. The study examines the current state of wear-resistant cladding technologies, identifies the principal failure mechanisms, and outlines future development directions.

Core Technical Content

Wear Mechanisms in Cement Equipment

The cement production process involves multiple stages — grinding, conveying, mixing, and transporting — each presenting distinct wear challenges. The dominant wear mechanisms include abrasive wear, erosive wear, adhesive wear, and in some cases, impact-abrasive combined wear.

Equipment Component	Wear Mechanism	Service Life (Uncladded)	Typical Abrasive Particle Size
Ball mill liners	Abrasive + Impact	6-12 months	0.05-2.0 mm
Rotary kiln wear plates	Abrasive + Thermal	3-6 months	0.1-5.0 mm
Conveyor chutes	Abrasive	1-3 months	0.01-0.5 mm
Fan impellers	Abrasive + Erosive	3-6 months	0.001-0.1 mm
Pipe elbows (pneumatic conveying)	Erosive	1-3 months	0.001-0.05 mm
Crusher hammers	Impact + Abrasive	3-6 months	0.5-10.0 mm

Wear-Resistant Cladding Materials and Systems

The study categorizes wear-resistant overlay materials into several major families based on their matrix composition and hard phase reinforcement strategy.

Material System	Hardness (HV)	Key Reinforcement Phase	Typical Application	Overlay Process
High-Cr cast iron (Cr20, Cr26)	600-900	Cr7C3, Cr23C6 carbides	Mill liners, kiln wear plates	SAW, ESW, Strip cladding
High-Mn austenitic steel (Mn18)	200-300 (as-welded) / 400-500 (work-hardened)	Eutectoid carbides, TWIP effect	Chutes, conveyor components	SAW, GMAW
High-Cr high-Mo alloy	500-700	Cr-Mo mixed carbides	Fan impellers, pipe elbows	PTA, SAW
Fe-Cr-C-Ni alloy	400-600	Cr7C3, Cr23C6, Cr3C	Kiln wear plates, chutes	SAW, ESW
Ceramic-reinforced composite	800-1200	WC, Cr3C2, SiC particles	Impact wear plates	PTA, Laser cladding
Ductile iron-based overlay	400-600	Spheroidal graphite + carbides	Ball mill liners	Strip cladding

Process Selection and Engineering Considerations

The selection of overlay process is governed by component geometry, production volume, and required coating thickness. Submerged arc welding (SAW) and electroslag welding (ESW) remain the dominant processes for thick overlay deposits (3-25 mm) on large flat or cylindrical surfaces such as mill liners and kiln wear plates. These processes offer high deposition rates (5-20 kg/h for SAW, 10-30 kg/h for ESW) and good metallurgical bonding.

For complex geometries such as fan impellers and pipe elbows, plasma transferred arc (PTA) powder cladding and gas metal arc welding (GMAW) overlay are preferred due to their flexibility and ability to produce thinner, more controlled deposits (1-5 mm). Laser cladding is emerging as a promising alternative for high-value components requiring thin, high-quality coatings with minimal heat input, though its cost per unit area remains significantly higher than conventional arc processes.

Engineering Practice Implications

The economic analysis of wear-resistant cladding in cement equipment is compelling. A typical ball mill liner cladded with high-chromium cast iron overlay can extend service life by 3-5 times compared to uncladded carbon steel, translating to significant reduction in downtime and replacement costs. The initial investment in cladding is typically recovered within the first maintenance cycle.

Application	Uncladded Life	Cladded Life	Extension Factor	Annual Savings (Estimated)
Ball mill liners (φ3.5m × 6m)	8 months	36 months	4.5×	200,000-400,000 RMB
Rotary kiln wear plates	4 months	18 months	4.5×	100,000-200,000 RMB
Pneumatic conveying pipe elbows	2 months	12 months	6.0×	50,000-100,000 RMB
Fan impellers	5 months	24 months	4.8×	80,000-150,000 RMB

A critical engineering consideration highlighted in the study is the residual stress management in cladded components. Heavy section mill liners and kiln wear plates are susceptible to residual stress cracking during and after cladding. Preheating to 200-300°C, controlled interpass temperature (150-250°C), and post-weld stress relief (PWHT) at 550-650°C are essential for preventing delayed cracking in high-carbon overlay deposits.

Development Prospects

The study identifies several future directions for wear-resistant cladding in the cement industry:

Development of functionally graded overlay systems that combine a tough transition layer with a hard surface layer to improve spalling resistance.
Application of high-entropy alloy (HEA) based overlay compositions offering exceptional hardness, wear resistance, and thermal stability.
Integration of process monitoring and in-situ quality control systems for automated strip cladding and PTA operations.
Advanced simulation of residual stress and distortion in large-scale cladding operations to optimize welding sequences and reduce distortion.
Expansion of cladding applications to previously uncladded components such as cement kiln shell wear plates, preheater cyclone wear plates, and cement mill trunnion sleeves.

Study Insights and Implications

This review serves as a valuable reference for engineers seeking to optimize wear-resistant cladding programs in cement processing facilities. The key insight is that wear-resistant cladding is not merely a surface treatment but a strategic engineering solution that fundamentally alters the lifecycle cost profile of abrasive-service equipment. The selection of overlay material, process, and quality control strategy must be tailored to the specific wear mechanism, operating conditions, and economic constraints of each application. The evolution toward higher-performance overlay systems — including ceramic-reinforced composites and advanced alloy compositions — continues to expand the boundary of what is achievable through weld overlay technology in the cement industry.