Friction Coefficient of Al 6082- steel / Wear

[edoxos]

Could anyone explain me, why when the friction coefficient

(al 6082 - steel) gets lower with bigger loads the wear

of al 6082 increases ?

Since the surface is hardened why wear increases ?

 

[Chinnia]

Please specify load, speed, geometry (pin-on-dic, etc) and the environment (dry ot lubricated).

If it is dry wear, I will be able to help as I have done hundreds of tests with several Al aloys against different substrates.

 

[edoxos]

Ok, i used pin on disk and the load was 2,5,10 and 20 N.

As for the speed 15,30,60 and 90 cm/sec.

It was dry wear and that is something that happens to most

metals- i mean that since we increase load the surface

gets harder but why does wear ?

 

[Chinnia]

Thanks for the details.

Considering the load and speed conditions of your tests, I think you should have observed some black debris. They are called equiaxed particles and corespond to Regime 1 in the wear maps for Al alloys.

Wear and friction coefficient (FC) do not always correlate to each other. My experience is FC varies between 0.4 and 0.6 in the load and speed range you have used. FC goes above 0.6, some times even close to 1.0 when the load and speed are very high where heavy plastic deformation occurs.

Wear rate also increased linearly high with load or speed up to a point and above which wear mechanism (how wear debris are produced) changes from one type to another and wear rate could increase or decrease.

It is a complicated picture as there so many parameters involved.

Please refer to a good tribology book such as I.M. Hutchings.

Best wishes.

 

[edoxos]

You have been very helpful !!

Thanks a lot. Wishes for the best !

Bye