2024年4月25日发(作者：贝珉)
表面光洁度表示符号（Surface finish is the symbol）
Surface finish is the old standard of surface roughness;
Their correspondence:
Surface finish level 14 = Ra 0.012
Surface finish level 13 = Ra 0.025
Surface finish level 12 = Ra 0.050
Surface finish level 11 = Ra 0.1
Surface finish level 10 = Ra 0.2
Surface finish level 9 = Ra 0.4
Surface finish level 8 = Ra 0.8
Surface finish level 7 = Ra 1.6
Surface finish level 6 = Ra 3.2
Surface finish level 5 = Ra 6.3
Surface finish 4 = Ra 12.5
Surface finish level 3 = Ra 25
Surface finish level 2 = Ra 50
Surface finish level 1 = Ra 100
Surface roughness units above is mu m, namely the micron = 10
^ 6 meters.
Surface roughness refers to the small spacing of the machining
surface and the unflatness of small peaks and valleys. The
distance between the two peaks or the trough (the wave length)
is small (below 1mm) and is indistinguishable from the naked
eye, so it is a microscopic geometry error. The smaller the
surface roughness, the smoother the surface. The size of
surface roughness has a great effect on the performance of
mechanical parts, mainly in the following aspects:
1) surface roughness affects wear resistance of parts. The
rougher the surface, the smaller the effective contact area
between the surface, the greater the pressure, the faster the
wear.
2) the surface roughness affects the stability of the matching
property. The rougher the surface, the more likely it is to wear
out, increasing the gap in the working process. In the case of
overturning, the joint strength is reduced by squeezing the
micro-convex peak and reducing the actual effective overgain.
3) the surface roughness affects the fatigue strength of the
parts. The surface of rough parts has large trough, they are
like sharp Angle gap and crack, they are sensitive to stress
concentration, thus affecting the fatigue strength of the
parts.
2024年4月25日发(作者：贝珉)
表面光洁度表示符号（Surface finish is the symbol）
Surface finish is the old standard of surface roughness;
Their correspondence:
Surface finish level 14 = Ra 0.012
Surface finish level 13 = Ra 0.025
Surface finish level 12 = Ra 0.050
Surface finish level 11 = Ra 0.1
Surface finish level 10 = Ra 0.2
Surface finish level 9 = Ra 0.4
Surface finish level 8 = Ra 0.8
Surface finish level 7 = Ra 1.6
Surface finish level 6 = Ra 3.2
Surface finish level 5 = Ra 6.3
Surface finish 4 = Ra 12.5
Surface finish level 3 = Ra 25
Surface finish level 2 = Ra 50
Surface finish level 1 = Ra 100
Surface roughness units above is mu m, namely the micron = 10
^ 6 meters.
Surface roughness refers to the small spacing of the machining
surface and the unflatness of small peaks and valleys. The
distance between the two peaks or the trough (the wave length)
is small (below 1mm) and is indistinguishable from the naked
eye, so it is a microscopic geometry error. The smaller the
surface roughness, the smoother the surface. The size of
surface roughness has a great effect on the performance of
mechanical parts, mainly in the following aspects:
1) surface roughness affects wear resistance of parts. The
rougher the surface, the smaller the effective contact area
between the surface, the greater the pressure, the faster the
wear.
2) the surface roughness affects the stability of the matching
property. The rougher the surface, the more likely it is to wear
out, increasing the gap in the working process. In the case of
overturning, the joint strength is reduced by squeezing the
micro-convex peak and reducing the actual effective overgain.
3) the surface roughness affects the fatigue strength of the
parts. The surface of rough parts has large trough, they are
like sharp Angle gap and crack, they are sensitive to stress
concentration, thus affecting the fatigue strength of the
parts.