Modern heavy industrial plants—ranging from multi-ton mining operations to massive cement calcining facilities—operate in environments of extreme mechanical stress. In these demanding conditions, structural steel components undergo rapid surface degradation due to heavy-duty wear, extreme sliding abrasion, impact stresses, and elevated temperatures. To combat this material loss, procurement teams globally are prioritizing advanced metal compounds. Tungsten (W) and Chromium (Cr) stand at the absolute pinnacle of metallurgy for wear protection.
Tungsten, featuring the highest melting point of all metals (3,422 °C) and a density that rivals gold, forms the metallurgical foundation of modern severe-wear mitigation. By synthesizing tungsten with carbon, manufacturers produce Tungsten Carbide (WC)—an interstitial compound with a hardness second only to diamond. Integrating these hard compounds into metallic matrix structures is a necessity for sectors processing highly abrasive materials like limestone, granite, sinter, and coal dust.
Procuring raw tungsten metal or carbide-based overlay plates involves navigating complex global supply chains. As a critical resource, raw tungsten is subject to geopolitical risk and export limitations. Consequently, global buyers are shifting their strategy from raw metal procurement to pre-engineered composite products. Utilizing prefabricated Chromium Carbide Overlays (CCO) and Tungsten Carbide hardfacing wires reduces fabrication waste and maximizes service life.
For large-scale industrial buyers, the total cost of ownership (TCO) is the primary metric. Purchasing high-quality hardfacing composites results in significant savings from reduced downtime and fewer maintenance intervals.
Understanding wear mitigation requires a detailed look at the microstructure of hardfacing overlays. Standard structural steel yields under high abrasive pressure because its ferrite-pearlite matrix lacks the hardness to resist sharp mineral particles. Hardfacing processes apply a highly alloyed coating to the surface, transforming it into a dense, wear-resistant layer.
| Alloy Family | Microstructural Phases | Hardness Range (HRC) | Primary Wear Mechanism Countered | Maximum Temperature Limit |
|---|---|---|---|---|
| Chromium Carbide Overlay (CCO) | Primary Cr7C3 Carbides in Austenite Matrix | 58 - 65 HRC | Severe sliding abrasion & moderate impact | approx. 350°C - 540°C |
| Tungsten Carbide (WC/W2C) | Spherical or Cast WC particles in Nickel/Cobalt matrix | 65 - 72 HRC | Extremely aggressive grinding abrasion | approx. 600°C |
| Bimetallic Alloys | Complex Carbides (Nb, B, Mo addition) | 60 - 67 HRC | Combined impact, corrosion, and wear | approx. 650°C |
Runxing’s bimetallic CCO plates are engineered via open-arc surfacing, depositing high-chromium, high-carbon alloys onto a structural steel backing. The resulting microstructure features high concentrations of primary hexagonal-shaped chromium carbides (Cr7C3) embedded in a tough eutectic matrix. The volume fraction of these primary carbides is tightly regulated between 30% and 45% to balance wear resistance with fracture toughness.
During the cooling phase of deposition, the differences in thermal expansion between the backing plate and the overlay trigger stress relief. This results in characteristic transverse hairline cracks. These stress-relief cracks do not compromise the integrity of the overlay; instead, they prevent warping and cracking during installation and bending.
For applications where CCO plates reach their performance limits, Tungsten Carbide hardfacing is used. Applying WC alloys typically involves Plasma Transferred Arc Surfacing (PTAW) or gas-shielded metal arc processes using specialized tungsten-rich flux-cored wires. The carbide particles remain solid during deposition, suspended within the molten nickel or cobalt iron matrix.
This microstructural composition creates an exceptionally tough barrier against wear. When abrasive minerals move across the hardfaced surface, the softer matrix wears down slightly, leaving the high-hardness tungsten carbide particles exposed to bear the load. This prevents further abrasive penetration and extends the service life of the component.
Critical components in cement production, such as vertical mill rollers, table liners, cyclone separators, and raw material feed chutes, face intense friction from high-speed abrasive flows. Raw material preparation involves crushing hard minerals, which can lead to rapid erosion.
Applying bimetallic CCO plates and automated roller repairs prevents premature wear, maintaining stable milling profiles and ensuring consistent raw meal fineness.
Mining operations subject equipment to aggressive wear under high load pressures. Excavator buckets, crusher linings, hopper systems, and slurry transfer systems require robust surface protection to withstand continuous impact and abrasion.
Tungsten-bearing alloys and thick-plate CCO overlays reinforce these critical points, allowing machinery to operate reliably through long campaigns without unplanned shutdowns.
Blast furnace components, coke distribution systems, and coal pulverizers in thermal power stations operate under severe thermal and abrasive stress. The combination of high temperatures and abrasive dust quickly degrades standard steel.
Specialized hardfacing wires, including carbon-controlled chromium-niobium-tungsten alloys, maintain structural integrity and surface hardness in these high-temperature environments.
Founded in 2010 and located in Tangshan, Hebei Province, Tangshan Runxing Machinery Co., Ltd. is a specialized manufacturer dedicated to the research, development, production, and on-site construction of hardfacing wear-resistant metal products. Leveraging a decade of metallurgical experience, our team develops surface protection solutions designed to withstand severe wear.
Our comprehensive catalog includes: chromium carbide overlay (CCO) wear plates, custom processed wear liners, wear-resistant pipes and fittings, hardfacing flux-cored welding wires, automatic surfacing equipment, and roll repair services. By focusing on advanced metallurgy and precise manufacturing, we supply key wear-resistant components to heavy industries globally.
Strategic Partners & Certifications
VAUTID Qualified Agent ISO 9001 Certified DIN 8555 Compliant
At the 2024 South Africa International Construction and Mining Machinery Exhibition in Johannesburg, Runxing presented its updated wear-resistant plates and automated surfacing systems to the African mining sector.
A research team from Tangshan University visited our production facilities to collaborate on developing advanced metal materials and forming technologies, helping to refine our alloy composition and structure.
Runxing Machinery has maintained its status as a qualified partner for VAUTID welding consumables for six consecutive years, supporting the production of premium-grade wear plates.
Runxing participated in EXPOMIN in Santiago, Chile, showcasing bimetallic liners and hardfacing solutions developed for South American copper and lithium mining installations.
The choice between CCO and Tungsten Carbide depends on the wear conditions. CCO overlays, containing chromium carbides (Cr7C3) with a hardness range of 58-65 HRC, are suitable for severe sliding abrasion and moderate impact at temperatures up to 540°C. Tungsten Carbide (WC) provides higher hardness (65-72 HRC) and is used in extreme grinding wear applications where impact is minimal, such as tunnel boring cutters and high-stress slurry pumps.
These surface fissures are stress-relief cracks that form naturally as the weld metal cools. They relieve residual stresses from the high-temperature open-arc cladding process, preventing distortion of the base plate during installation or fabrication. These cracks stop at the fusion boundary and do not affect the performance of the wear-resistant overlay.
Key parameters include chemical composition (primarily Carbon, Chromium, and Manganese levels), welding current, voltage, travel speed, and shielding gas configurations. Our self-shielded open-arc wires run without external gas shielding, using slag-forming compounds in the core to protect the weld pool. This makes them suitable for outdoor field repairs.
Rebuilding vertical coal or cement mills requires selecting alloys that match the original equipment manufacturer’s hardness and toughness profile. The process involves removing the work-hardened surface layer, applying a ductile buffer layer to prevent cracking, and rebuilding the profile with high-chromium or tungsten-modified alloys using automated welding equipment.
Hebei Yuwan International Trade Co., Ltd. serves as our authorized export agent. They manage logistics, customs documentation, and payment processing, while the Tangshan factory focuses on production and quality control to ensure order accuracy and timely dispatch.
Runxing machinery