Application Features of Diamond Grinding Wheel in HVOF WC Coating Grinding
Diamond grinding wheel has been used in processing HVOF WC coating. Here analyze the features of HVOF and the problems of the diamond grinding wheel in grinding.
High-Velocity Oxygen Fuel is called HVOF. The tungsten carbide (WC) coatings are made by this technology. They have a higher hardness (over HV1200) and higher wear resistance (three times longer wear life than hard chromium coatings) than electroplating hard chromium. At the same time, tungsten carbide coatings do not pollute the environment.
HVOF WC Application
With the excellent performance of HVOF coating, it has been applied in many fields, such as civil steam turbine, aero engine, automobile, papermaking, petrochemical, iron and steel metallurgy, biomedicine and etc.
In the aeronautical field, HVOF has been applied to aero-engine components such as bearing sleeve, a compressor blade, compressor stator blade and etc. They have basically achieved standardization.
In the papermaking industry, some parts should be around once every half to four months to ensure the good surface finish of various working rollers. The mirror HVOF WC-Co coating is sprayed with the thickness of 0.1mm. The surface finish of the coating is the same as that of the initial surface after 15 months of use.
In iron and steel metallurgy industry, the tension rollers for steel winding are strengthened by hard chromium plating. Its life is only 2.5 months. The 1mm WC-Co coating sprayed by HVOF can be used for 5 years or more.
In the petrochemical industry, HVOF is widely used to strengthen the piston rod and ball valve. HVOF WC-Co coating, WC-Ni coating, and Fe-Cr-Ni-Mo coating are widely used for metal seat ball valves that are in pipeline with corrosive mortar working at 140MPa and 540℃. It greatly improves the corrosion resistance and erosion resistance of ball values, thus improves the reliability and life of the equipment.
Features of Grinding HVOF WC Coating with Diamond Grinding Wheel
With the high hardness and wear resistance of HVOF WC coating, there are following technical difficulties in the grinding process of a diamond grinding wheel.
1. Great loss of grinding wheels, frequent dressing, and replacement of grinding wheels.
2. Low processing efficiency, difficult to control shape, dimension accuracy, and surface accuracy.
3. The bonding between tungsten carbide and metal matrix is a mechanical bond. The bonding is low and the grinding force in grinding process has an influence on the bonding of the coating interface.
4. There are voids in tungsten carbide coating, and the thermal conductivity of coating and interface is not good. The thermal accumulation in the grinding process causes thermal damage to the matrix, which affects the mechanical performance of a metal matrix. Therefore, it is very important for temperature control technology in the grinding process.
5. The internal of tungsten carbide coating made by HVOF is compressive stress state.
Grinding can affect stress state, thus affecting crack growth and life.
In short, the grinding process has an impact on the structure, performance and process method of tungsten carbide coating. So there are many uncertainties in the processing of the workpiece.
With the development of technology, besides the processing method of the diamond grinding wheel, there are also electrolytic grinding and thermal spray coating of resin diamond abrasive belt. Every method has its own features. Click the related links to get detailed information.