Industry Overview
Thermal power plants - whether coal-fired, biomass, or waste-to-energy — operate around the clock under some of the most demanding conditions for wear parts. Coal and biomass fuels contain abrasive mineral matter (aluminosilicates, quartz) and corrosive compounds (chlorides, sulfates, alkalis) that accelerate wear across every system: coal grinding, ash handling, slag removal, and flue gas treatment. Extended wear life directly translates to fewer forced outages and higher power generation revenue.
Zhili has extensive experience supplying power plant operators worldwide with wear-resistant and heat-resistant components for coal mills, biomass grinders, boiler slag systems, ash handling, and flue gas treatment. Our solutions optimize plant availability, reduce maintenance costs, and extend the life of critical components in both pulverized coal (PC) and circulating fluidized bed (CFB) boilers.
Related Products for Power Generation
VRM Grinding Table & Liners
Vertical roller mill tables and liners for coal grinding in 300-660 MW units. High-chromium bimetal overlay or CrC hardfacing for maximum abrasion resistance against high-silica coal.
Grinding Roller / Extrusion Roller
Coal mill grinding rollers with high-chromium overlay or ceramic composite surfaces. Designed for Babcock, LOESCHE, and MPS vertical roller mills with 20,000+ hour service life.
Ball Mill Grinding Media & Liners
High-chromium grinding balls (HRC 58-63) and wear-resistant ball mill liners for coal ball mills in older power plants and biomass applications. Optimized for maximum wear life in moist, abrasive fuel environments.
Dam Ring & Nozzle Ring
CFB boiler and coal mill dam ring segments with high-temperature wear resistance. Precision-cast heat-resistant alloy with extended service life in high-velocity particle environments.
Wear Liner Plates for Ash Handling
High-wear zones in ash hoppers, pneumatic ash conveying lines, and slurry pipelines. High-chromium bimetal or ceramic-reinforced composite for the most abrasive fly ash compositions.
Hardfacing Flux-Cored Wire
Premium flux-cored wires for rebuilding worn coal mill components in-situ. CrC, WC, and NbC carbide overlay options for rebuilding grinding rollers, table segments, and classifier blades.
Core Material System for Power Generation
The primary material for coal mill grinding tables, rollers, and classifier components. Chromium carbide overlay applied by submerged arc welding (SAW) or FCAW creates a dense, crack-free wear surface with 45-55% M₇C₃ carbide volume fraction. Multi-pass application (up to 6 layers) ensures deep substrate bonding and consistent through-thickness properties.
| Surface Hardness | HRC 55-63 |
| Carbide Type | M₃C / M₇C₃ eutectic (Cr 15-28%) |
| Overlay Thickness | 8-20 mm per pass |
| Bond Strength | > 350 MPa |
| Material Basis | High Chromium Cast Iron overlay (SAW/FCAW) |
| Application | Coal mill tables, rollers, ash hoppers, chutes |
Circulating fluidized bed (CFB) boilers operate at 800-900°C with highly abrasive bed material (sand, limestone, ash). Water wall panels, cyclone diplegs, and loop seal components require heat-resistant alloys that maintain structural integrity under thermal cycling while resisting erosion from high-velocity (5-15 m/s) solid particle streams.
| Grades | ZG35Cr24Ni7N, ZG35Cr28Ni48 |
| Operating Temp | ≤ 950°C (CFB combustor) |
| Erosion Resistance | 15 m/s particle velocity rated |
| Application | CFB water walls, cyclones, loop seals, hot air ducts |
Fly ash — the fine particulate remaining after coal combustion — is extremely abrasive due to its glassy, angular particle morphology and silica content. High-chromium bimetal composite (HRC 60+ wear surface) is the standard solution for ash hoppers, pneumatic conveying lines, and slurry pipelines in power plants.
| Wear Surface | HRC 58-63 (HCrCI, Cr 18-22%) |
| Backing Steel | Q&T structural steel |
| Thickness Range | 6+20 mm to 10+30 mm |
| Ash Abrasion Index | Tested for AI 0.4-0.8 (high silica ash) |
Raymond bowl mills and dynamic classifiers in older power plants use Whizzer blades, bowl liners, and banded springs operating at 150-250°C with high-silica coal dust. Zhili provides precision-cast and machined components from heat-treated alloy steels with optional tungsten carbide hardfacing on critical wear zones.
| Base Material | 35CrMo / 42CrMo Q&T alloy steel |
| Hardness | HRC 40-48 |
| Optional Surfacing | Tungsten carbide overlay (HRA 88-92) |
| Application | Raymond mill bowls, classifier blades, grinding rings |
Typical Application Scenarios
Coal Mill Grinding Tables & Rollers
VRM or ball mill grinding coal from low-rank lignite to high-ash anthracite. High-silica mineral matter causes severe three-body abrasion on table and roller surfaces at 150-200°C.
CrC Overlay Table & RollersCFB Boiler Cyclone & Loop Seal
High-velocity (10-15 m/s) circulating sand and ash particles erode cyclone walls, diplegs, and loop seal components at 850-900°C. Erosion-corrosion is the primary failure mode.
Heat-Resistant Erosion AlloyAsh Hopper & Pneumatic Conveying
Fly ash collected in hoppers and pneumatically conveyed at 2-5 m/s creates severe wall abrasion. Ceramic-tile or bimetal-lined hoppers provide maximum wear life for bottom ash and fly ash handling.
Bimetal / Ceramic Lined HoppersBoiler Slag Screen & Ash Cooler
Slag screen tubes and rotary ash coolers process molten boiler slag at 1,000-1,200°C. Combustion residue with high alkali and sulfide content creates aggressive corrosive-abrasive wear.
Heat-Resistant Alloy · Corrosion ResistantClassifier Blades & Bowl Liners
Dynamic and static classifiers separate fine coal particles (R90 < 2%) from coarse rejects. Classifier blades operate at high RPM with abrasive coal dust — tungsten carbide overlay on leading edges is the optimal solution.
WC Overlay Classifier BladesFlue Gas Duct & Air Preheater
Flue gas ducts and rotating air preheater elements at 250-400°C face condensation corrosion (acid dew point) in low-load conditions plus fly ash erosion. Austenitic stainless or specialized erosion coatings are used.
Stainless Steel / Erosion CoatingSuccessful Cases
Coal Mill Grinding Rollers — 660 MW Supercritical Unit
CFB Boiler Cyclone Diplegs — 350 MW CFB Unit
Ash Handling Pipeline — 500 MW Subcritical Unit
Dynamic Classifier Blades — 800 MW Lignite Power Plant
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