Two ways to improve the hardness of the grinding wheels:
1, To improve the hardness of grinding wheel with sodium silicate solution.
Vitrified abrasive tools can be treated by immersing them in sodium silicate solution of certain concentration. The specific gravity of the solution can be determined according to the particle size, hardness or hardness level need to be achieved of grinding wheels.
Handling method:
When making up the solution, the solution should to be heated to 80~90℃ first. And the specific gravity of solution need to be measured by a hydrometer at 15~17℃. After that, pouring the solution prepared into the container that is used to process the abrasive tools, then put the abrasive tool flat on the holder of the container ((20~30mm high), and make 1/5 of the thickness of the abrasive tools exposed above the solution surface, so that the air in the pore of the abrasive tool can be discharged. When the solution appears on the upper part of the abrasive tools, it can be taken out, then place it on the holder with holes, and be blow dried with fan or air dried. Generally, it will take 12 hours for a small abrasive tool and 48 hours for a large abrasive tool. During drying, turn the tool every 15 minutes to prevent solution from flowing to one side which can cause uneven hardness of the abrasive tool. After the grinding tool is dried, it should be put in the oven at 100~220℃ for 4~12 hours.
2, To improve the hardness of grinding wheel with synthetic resin liquid.
Immersing the abrasive tool into the mixture (the resin is soluble in water and the same volume of alcohol), and then heated to 60℃. The concentration of the solution can be determined according to the original hardness and hardness level need to be achieved of grinding wheels.
Handling method:
Putting the abrasive tool flat on the holder of the container ((20~30mm high), and make 1/3 of the thickness of the abrasive tools exposed above the solution surface. When no solution appears on the upper part of the tool, take it out and stack it for natural drying. Generally, abrasive tools less than 200mm in diameter need to be dried for 8 hours, and greater than 200mm in diameter need to be dried for 20 hours. During drying, turn the tool every 15 minutes. Then it is gradually heated to 160~180℃ in the oven for hardening, and lasting about 8~24 hours.
