Technical requirements for granite slabs

Technical requirements for granite slabs

1. There must be no defects such as sand holes, air holes, cracks, slag inclusions, shrinkage, scratches, bumps, rusts and other defects that seriously affect the appearance and use performance.

2. The depressions or corners on the non-working surface of the flat plate are allowed to be repaired.

3. The plate should be made of fine grains and densely structured gabbro, diaphragm, and granite (the black mica should be less than 5%, and the elastic modulus should be greater than 0.6×10—4kg/cm2, water absorption rate should be less than 0.25%) and other materials, the working surface hardness should be greater than 70HS.

4. The allowable value of the surface roughness Ra of the flat panel working surface is 0.32~0.63um, and the side is 10um.

5. The planarity tolerance of the flat surface of the flat surface is shown in Table 1.

6. When using the diagonal method or grid method to check the plane plane of the plate, the gas plane fluctuation should be checked. The plane fluctuation of the working face is shown in Table 2.

7. The verticality tolerance of the working surface on the side of the flat plate and the verticality tolerance of the two adjacent sides of the flat plate are both 12 levels specified in GB/T1184.

8. The centralized load area, applied rated load and allowable deflection values in the center of the flat panel working surface are shown in Table 3.

9. It is recommended not to set up a handling handle for level 000 and level 00 tablets.

10. If threaded holes (or grooves) are installed on the flat surfaces of the 0 and 1st grade plates, the location should not be higher than the working surface.

Table 1

Table 2 um

Table 3