earticle

영어

Both traditional grinding and micro cold pressing are conducted to compare the micro surface morphologies of cold work mold steel specimen. Surface roughness, hardness and surface morphologies are analyzed under varying feeds of ball end cutter in Y direction and Z direction in MCP. The friction coefficients and wear rates of two types of specimen under oil lubrication are obtained through friction and wear test. After micro cold pressing, hardness increases from 0.11 to 0.099, with surface roughness reduced from 5.496μmto 1.871μm and wear rate reduced from 0.0506μm to 0.0153μm (Wear rate is measured in Z direction). The study shows that during micro cold pressing the ball end cutter flattens wear scar, which reduces surface roughness. Surface roughness is related to DY and DZ. Under fixed DZ, reduction in DY leads to an increase in flatness of specimen surface. Since work hardening takes place during micro cold pressing, surface hardness of specimen has improved with the greatest increment at 169.6HV.Grooved surface morphology is obtained by micro cold pressing. The depth of groove is related to DY and DZ. When DZ is fixed, depth of groove is smaller when DY is 0.05mm than that when DY is 0.1mm. Under fixed DY, the depth of groove increases with the increase of DZ. Surface quality (including surface roughness, roughness and surface morphology) affects friction coefficient and wear rate. Reasonable surface quality not only decreases friction coefficient but also decreases wear rate. Friction coefficient can be reduced by 10% while wear rate can be reduced by 69.76%.