Friction factor

[jamesXIII]

Hello to everybody,
I'm looking forward materials which have a friction factor of about 0.2 (lubricated) and the higher hardness.
Does it make sense to search such marterial?
In advance thanks!
JamesXIII

Electro-mechanical designer

 

[diamondjim]

Can you be more specific about the material
you want to use? Also the typical hardness?

 

[jamesXIII]

hello diamondjim,

The hardness would be around 50HRC, I wanted to use steel but the steel-steel friction factor is about 0.1. Do you have any idea of material pair which will have a friction factor of 0.2 with lubrication

Electro-mechanical designer

 

[cloche]

You can use powders like "Carborundum" on the steel-base contacting surfaces. Dry steel-steel + carborundum raises up the friction factor to 0.5.
Roughening the contacting surfaces can raise it up to 0.25 / 0.3 (but you have to check if there aren't any drawbacks...)

 

[Tmoose]

I think Type F automatic transmission fluid is around that range at low sliding velocities. Might be more controllable than almost mythical coefficient of friction, which seems to have a range of values despite hosts of published data.

 

[ccw]

Hi jamesXIII,
for what it is worth, Machinerys Handbook 25th Ed. p.190 Table 2 "Coefficients of Static Friction for Various Material Combinations" shows sapphire on sapphire = 0.2 for dry and 0.2 for lubricated. Sapphire is hard so this meets your criteria. However, I think you will need to establish an allowance band or additional critera to arrive at anything meaningful.