Surface Wear

[kuds]

Hello All,
I had a question regarding surface wear and I was wondering if anyone could suggest me some books/people/reference material for the same. The question is how does one characterize surface wear. In other words, if a component undergoes wear over a period of time of its operation, then has wear got any units by which it can be measured? How do I say that a certain component has got a certain amount of wear? Any help would be appreciated.

Thanks.

 

[tomwalz]

You might find information under tribology.

In tungsten carbide tools they measure mass loss. Specifically recession on a cutting edge measured as radius in microns of a cutting edge. However different edges wear differently. There can also be erosion of the flat sides different than edge erosion so you get a dishing in what once was a flat surface.

Edge recession is used because that is the area that typically most effects performance.

With piping I suppose it would be pipe thickness at an elbow.

Here is a list I developed. It works but it has a feel to it that it could be better. The primary purpose is to explain wear factors to industrial tool users such as saw filers.

Theoretical considerations
1. Wear – the grains and the binder just plain wear down
2. Macrofracture – big chunks break off or the whole part breaks
3. Microfracture – edge chipping
4. Crack Initiation – How hard it is to start a crack
5. Crack propagation - how fast and how far the crack runs once started
6. Individual grains breaking
7. Individual grains pulling out.
8. Chemical leaching that will dissolve the binder and let the grains fall out.
9. Rubbing can also generate an electrical potential that will accelerate grain loss
10. Part deformation - If there is too much binder the part can deform.
11. Friction Welding between the carbide and the material being cut
12. Physical Adhesion – the grains get physically pulled out. Think of sharp edges of the grains getting pulled by wood fibers.
13. Chemical adhesion – think of the grains as getting glued to the material being cut such as MDF, fibreboard, etc.
14. Metal fatigue – The metal binder gets bent and fatigues like bending a piece of steel or other metal
15. Heat – adds to the whole thing especially as a saw goes in and out of a cut. The outside gets hotter faster than the inside. As the outside grows rapidly with the heat the inside doesn’t grow as fast and this creates stress that tends to cause flaking (spalling) on the outside.
16. Compression / Tension Cycling - in interrupted cuts the carbide rapidly goes though this cycle. There is good evidence that most damage is done as the carbide tip leaves the cut and pressure is released.
17. Tribology – as the tip moves though the material it is an acid environment and the heat and friction of the cutting create a combination of forces.

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

 

[unclesyd]

In addition to tomwalz's you might want to look at the excellent paper by Peter Min.

http://www.solorb.com/dat-heads/digests/V4.100/D100

A paper specific to carbides.

http://www.scielo.br/pdf/jbsmse/v28n2/29746.pdf

A very good source of information on wear and a whole lot of other things.

http://www.tribology-abc.com/

 

[coatingengineer]

Hi,

Tom of Carbide Processors has sure given you great advice.

'Wear', you see, can manifest in a variety of ways. But don't let that discourage you. Because, in most cases, you'll discover a visual characteristic of most every wear mechanism.

For additional (tribological) help, see:
<a href="

http://www.industrialcoatingsworld.com/Wear-Resistant-Coatings/index.html">Wear

Resistant Coatings</a>

Hope this helps.
William



William Gunnar

http://www.IndustrialCoatingsWorld.com