material property for wear 1

[arnoldh]

Hi folks,

I am currently benchmarking the wear beahavior of some different materials against a constant materials. As far as I understood, an important material property is the hardness. The hardness of the material which is used as wear partner is appr. 60 HRC. The material with the best behaviour is a PH-steel and has a hardness of appr. 48 HRC. One of the materials which I expected to be better (a martensitic steel) has a hardness of appr. 51 HRC. Against my expectations, the wear rate of this material is a lot higher. I am now thinking that this has to do with a particular material property. Does anyone know of a material property which would make a comparison between materials possible and would clarify the above?

Some additional information regarding the test conditions:
The sliding speed, sliding distance and load are the same for each test. The surface roughenss I have to countercheck for the parts, but should be similar (at least they are on the drawing )).

 

[richardbuss]

Hi Arnoldh,

you should think about adhesive wear as well.

Regards
Richard Buss

 

[unclesyd]

In you situation you will have enough variables to write a book.
There is one thing that a lot of people over look in testing for wear and that is speed of the components. If you test on a machine like a Taber Met-Abrader this is accounted for by comparing at two different speeds, usually 105 RPM and 415 RPM.

For very low speeds the button and block test is an indicator for the potential for galling. Though not a direct correlation it will help determine the behavior in real life. It will tell you whether the materials will be able to rub and eventually wear.

You need to get some tables of self-mated and dissembler coupled materials as a guide for your testing.

 

[CdotS]

A simple rule of thumb is self-mated couples do not form a good wear system. Among the dissimilar metal combinations, you should look for those metals that have no or limited solid solubility. The solubility data can be found from binary diagrams. They work generally well. I have not seen any recent interest from researhers in this area.

There is a nice diagram published many years ago for pure metals. Refer to page 206 of Ian Hutchings' book titled Tribology - Friction and wear of engineeirng materials (Edward Arnold). Other tribology and wear books may have this diagram.

 

[gciriani]

One parameter that should correlate well with wear is the friction coefficient. One of my books says that worn material is in proportion to the energy dissipated. Therefore the higher the friction the more material should be worn away. In turn I suspect that roughness has a lot to do with friction.