(1) Affect the wear resistance

The rougher the surface, the smaller the effective contact area between the mating surfaces, the greater the pressure, the greater the frictional resistance, the faster the wear.

(2) Affect the stability of the fit

For clearance fit, the rougher the surface, the easier it is to wear, so that the gap gradually increased in the working process; for the interference fit, due to the assembly of the microscopic peaks will be flattened, reducing the actual effective interference, reducing the strength of the connection.

(3) Affect the fatigue strength

Rough parts of the surface of the presence of large valleys, they are like sharp notches and cracks, sensitive to stress concentration, thus affecting the fatigue strength of the parts.

(4) Affect the corrosion resistance

Rough parts surface, easy to make corrosive gases or liquids through the surface of the microscopic valleys penetrate into the inner layer of the metal, resulting in surface corrosion.

(5) Affect the sealing

Rough surfaces can not be tightly fit between the gas or liquid leakage through the gap between the contact surface.

(6) Affect the contact stiffness

Contact stiffness is the ability of the parts bonding surface to resist contact deformation under the action of external forces. The stiffness of the machine depends largely on the contact stiffness between the parts.

(7) Affect the measurement accuracy

The surface roughness of both the measured surface of the part and the measuring surface of the measuring tool will directly affect the accuracy of the measurement, especially in precision measurement.

In addition, the surface roughness of the parts of the plating and coating, thermal conductivity and contact resistance, reflective ability and radiation properties, the resistance of liquid and gas flow, the current flow on the surface of the conductor will have a different degree of influence.