Why use black silicon carbide P series to produce water-abrasive sandpaper?
Black silicon carbide P series include P12 P16 P20 P24 P30 P36 P40 P50 P60 P80 P100 P120 P150 P180 P220 P240 P280 P320 P360 P400 P500 P600 P800 P1000 P1200 P1500 P2000 P2500 P3000 P4000 P5000
Water-abrasive sandpaper chooses black silicon carbide P series as abrasive grains, mainly based on its physical properties, production process adaptability and comprehensive advantages of grinding effect. The specific reasons can be analyzed from the following three aspects:
1. Special design of P series products and matching with coated abrasives
Particle size concentration and grinding efficiency
The P series (“P” stands for coated purpose) has a highly concentrated particle size distribution (such as a high proportion of basic particles in P600) through strict screening and pickling processes, and the content of large particles and fine dust is extremely low. This feature enables the abrasive grains to be evenly distributed on the sandpaper substrate, avoiding scratches or ineffective grinding caused by uneven particle size, and significantly improving grinding efficiency.
Comparison: The F series (for bonded abrasives) has a wider particle size range and is more suitable for thick layer bonding scenarios such as grinding wheels.
Hydrophilicity and wet environment adaptation
P sand has undergone two pickling processes to remove impurities such as free carbon and silicon left over from smelting, and has high surface cleanliness and excellent hydrophilicity. During the water grinding process, water molecules can quickly wet the surface of the abrasive particles, forming a stable cooling and lubricating film, reducing blockage and extending the life of the sandpaper.
Particle shape and cutting force
P sand uses a special shaping process to form a multi-faceted pyramid or diamond structure (rather than a circle), with sharp edges and high compressive strength (compressive strength of 186kN/cm²). This shape can continuously maintain cutting force during water grinding, quickly remove materials instead of simply rubbing.
2. The material advantages of black silicon carbide in water grinding scenes
High hardness and wear resistance
Black silicon carbide has a Mohs hardness of 9.2–9.3, second only to diamond, and can efficiently grind high-hardness materials such as glass, ceramics, and stone. Its wear resistance is better than corundum, and it can still maintain cutting stability in a wet environment, reducing the frequent replacement of sandpaper.
Chemical stability and rust resistance
In the water grinding environment, the abrasive particles need to be in contact with water and metal debris for a long time. Black silicon carbide is chemically stable within the pH range of 4–13, is not easily oxidized or hydrolyzed, and does not contain ferromagnetic substances (magnetic substances ≤ 0.02%), which prevents water from rusting and contaminating the surface of the workpiece.
Thermal conductivity and thermal shock resistance
Silicon carbide has a high thermal conductivity (about 120W/m·K), which can quickly conduct the heat generated by grinding and prevent local overheating from causing deformation of the substrate. Its thermal expansion coefficient is low (4.4×10-6/℃), and it is not easy to crack in the alternating hot and cold water grinding scene.
3.Specific requirements of the water grinding process for the P series
Reduction grinding and surface accuracy requirements
Water grinding is often used for fine polishing (such as automotive paint and stainless steel finishes), and deep scratches need to be avoided.
The concentrated particle size of P sand can control the cutting depth, combined with the matte effect (the surface roughness of black silicon carbide after grinding is uniform), it is easy to achieve Ra0.02–0.04μm level finish
Adhesion requirements for flexible substrates
The substrate of water-abrasive sandpaper (such as sponge and cloth) requires strong interlocking of abrasive grains.After pickling, the surface micropores of P sand increase, and the anchoring effect is improved by more than 30% when bonded by resin, which significantly reduces the sand removal rate.
Environmental protection and work safety
Black silicon carbide P sand does not contain heavy metals (Fe₂O₃≤0.1%), and the waste liquid generated by water grinding is easier to handle. Its low dust characteristics (suspended matter is reduced by more than 50%) also ensure the air quality of wet operations.
Conclusion
The choice of black silicon carbide P series for water-abrasive sandpaper is essentially the synergistic result of material properties (high hardness, chemical inertness) and process adaptability (hydrophilic design, concentrated particle size, sharp shape). It not only meets the core needs of water grinding scenes for heat dissipation, rust prevention and fine polishing, but also further optimizes grinding efficiency and life through special processes (such as pickling and shaping), becoming an irreplaceable option in the field of coated abrasives.