Yongjia Tong Ball Valve Co., Ltd.: Your Professional Coated Valve Seats Manufacturer!
Founded in 2009, Tong Ball Valve Co., Ltd. is a national high-tech enterprise specializing in precision valve balls for severe service applications. We provide reliable solutions for global industrial valve manufacturers through advanced material processing, precision machining, and surface coating technologies. With strict quality control and full production traceability, our products are widely used in oil & gas, petrochemical, power generation, and other demanding industries worldwide.
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Why choose us?
Advanced materials & surface engineering
We specialize in difficult-to-machine materials including duplex stainless steel, titanium, Inconel, zirconium, and engineering ceramics. Combined with HVOF, plasma spray, DLC/TiN coating, and laser cladding technologies, our valve balls deliver excellent wear resistance, corrosion resistance, and long-term sealing performance.
Experienced technical support & global supply
Supported by a technical team with over 30 years of industry experience, we offer customized valve ball solutions based on different application requirements. As an authorized supplier for global companies including Emerson and Flowserve, our products have been exported to more than 20 countries and regions
Precision manufacturing for severe service
Our machining accuracy reaches roundness ≤0.001 mm, supporting stable sealing performance under high pressure, high temperature, and corrosive working conditions. Products are validated through rigorous cycle testing to ensure durability and operational reliability.
Strict quality control & full traceability
From raw material inspection to final testing, every production process follows strict quality standards. We provide 100% inspection and complete production traceability, helping customers reduce quality risks and improve supply chain confidence.
Types of Coated Valve Seats
Cobalt-based overlays (Stellite™)
These are standard, industry-proven cobalt hard facings. Applied using "spray and fuse" or welding techniques, alloys like Stellite 6, 12, or 50Nb offer excellent resistance to heat, galling, and wear. They are widely utilized in severe-service ball valves and high-temperature internal combustion engines.
HVOF (high-velocity oxygen fuel) coatings
This robotic thermal spray process applies extremely dense layers of hard materials—like Tungsten Carbide or Chrome Oxide Ceramics—onto a metal substrate. HVOF is the preferred coating for severe-service industrial valves because it bonds mechanically to the metal, creating a highly wear-resistant barrier against abrasive fluids and gases.
Chrome plating
Traditional hard chrome plating is applied to metal valve seats to improve sliding properties and reduce friction. It is commonly used in ball valves to extend service life in mildly abrasive fluid applications.
Nitriding
While technically a surface hardening treatment rather than a traditional coating, nitriding diffuses nitrogen into the surface of steel valve seats. This creates a hardened case that significantly boosts abrasion and wear resistance without altering the part's dimensions significantly.
Cold spray copper alloys
Commonly seen in advanced, high-performance engine designs, this technique sprays copper-based alloy coatings directly onto the base material (such as a cylinder head). This eliminates the need for press-fitted seats and provides excellent heat dissipation and elasticity.
Product Specifications
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Chromium Oxide-Coated Valve Seats |
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Size Range |
1/2" to 56" (Custom sizes available) |
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Pressure Rating |
PN10-PN420 (Class150-2500) |
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Body Material |
A105, A350 LF2, A182 F304, A182 F316, A182 F321, A182 F51, A182 F53, A182 F55, A182 F60, A182 F44, A564 630 (17-4PH) |
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Core Process/Coating |
ENP,HCR,STL6, STL12, STL20,Cr3C2, WC-Co, WC-Cr3C2-Ni, TiC-NiMo, SiC, CrC,ZrO2, Al2O3, Cr2O3, ZnO, TiO, Al2O3-TiO2,STL1, STL6, STL12,Ni60, Ni55, Ni45 etc. |
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Operating Temperature Range |
≤1200°C |
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Parameter Category |
Core Technical Parameters |
Standards for Determining Advanced Technological Level |
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Machining Seat accuracy |
≤ 0.025 mm |
≤ 0.005 mm (Ultra-High Precision) |
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Processing Seat Roundness |
≤ 0.025 mm |
≤ 0.011 mm (Micron-Level ) |
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Seats concentricity |
≤ 0.025 mm |
≤ 0.005 mm (Ultra-High Precision) |
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Other supplements |
≤ 0.4 μm |
≤ 0.1 μm (Mirror-Level) |
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Parameter Category |
Core Technical Parameters |
Criteria for High-End Technical Level |
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Coating Thickness Control |
Thickness Uniformity |
Thickness deviation at any spherical position ≤±8% (stricter than the general ±10% standard) |
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Thickness Tolerance Range |
100 - 300 μm (common range for wear-resistant layers); special ranges can be noted. No missed spraying for ultra-thin coatings (<10μm) |
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Coating Adhesion Performance |
Surface Hardness |
HV 1300+ |
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Bond StrengthBond Strength |
≥80 MPa |
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Interface PorosityInterface Porosity |
<0.5% |
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Coating Surface Quality |
Surface Roughness (Ra) |
≤0.2 µm |
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Spraying Accuracy (Positioning & Coverage) |
Spraying Positioning Accuracy |
±0.1mm |
Application of Coated Valve Seats
Automotive and internal combustion engines
In high-performance and modern passenger engines, coated valve seats—and sometimes coated valves—address the harsh conditions caused by low-sulfur or alternative fuels.
Industrial and severe-service valves
In industrial sectors like oil and gas, chemical processing, and mining, valves are subjected to highly corrosive, abrasive, and high-pressure environments.
Industrial soft-seated valves
For lower-pressure industrial uses, such as in butterfly or ball valves handling water or mild chemicals, seats can be coated or encapsulated with resilient polymers.
Packaging and Shipping
Certifications
FAQ
With abundant machining experience, we are one of the most professional coated valve seats manufacturers in China. We warmly welcome you to buy coated valve seats at competitive price from our factory. If you have any enquiry about cooperation, please feel free to email us.
Chromium Carbide Valve Seats, Titanium Coated valve Seats, Chromium valve Seats
