granite tri-square ruler

Granite Tri-square


Product specialty is as the following:

1.Made of high quality Natural Black Granite
2.High precision and high stability.
3.No rust and anticorrosion.
4.Non magnetization.
5.Good abrasion resistance.


Physical Property of Natural Black Granite:

1.Specific Gravity: 3.03 g/cm3
2.Shore Hardness: > 70Hs-80Hs
3.Tensile strength: 211Kg/cm2
4.Compressive Strength: 245-254Mpa
5.Linear Expansion Coefficient: 4.61´10--6/°C
6.Elastic Modulus: 30-50Gpa
6.Water Absorptivity: ≤0.13%