carburised vs carbonitrided - which has a better wear resistance
carburised vs carbonitrided - which has a better wear resistance
(OP)
For the same hardness and depth, does carbonitrided case has a better wear resistance than a carburised case?
Involved in a project where we need to double the life of a bush. At present the bush wears out in one year. We need it to last two years. It's mating/sliding contact with a roller.
Involved in a project where we need to double the life of a bush. At present the bush wears out in one year. We need it to last two years. It's mating/sliding contact with a roller.





RE: carburised vs carbonitrided - which has a better wear resistance
- surface friction and lubrication
- non-metallic inclusion content
- residual stresses
- microstructure including retained austenite
Ceramics are also used in certain applications like rolling contact bearing (ball bearings) because they can improve rolling contact resistance in certain environments (high temperature, poor lubrication).RE: carburised vs carbonitrided - which has a better wear resistance
They are a sub component in a farm machinery. We know there is no regular lubrication regime.
The solution being discussed around the table is to increase the case hardness and depth of the bush and hardness of the roller.
I can see the improvement if case hardness of bush is increased, keeping the roller hardness unchanged, thus making it sacrificial.
I can't see where is the improvement comes from if hardness of both contacting/sliding surfaces are increased?
RE: carburised vs carbonitrided - which has a better wear resistance
RE: carburised vs carbonitrided - which has a better wear resistance
And it will cost something.
There are some PVD coatings that work very well with lack of lubrication.
And don't rule out ceramics, they are not that expensive and the wear can be fantastic.
making both harder will reduce wear, but you need to make sure that the substrate provides enough support to prevent compressive load failure of hte wear surface. You may need stronger material if you go harder at the surface.
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Plymouth Tube
RE: carburised vs carbonitrided - which has a better wear resistance
Of the arrangement and also the worn parts
RE: carburised vs carbonitrided - which has a better wear resistance
Regarding carburized versus carbonitride surfaces, the primary difference is that carburizing can produce a thicker case, but the outer surface of a carbonitrided part will be a bit harder. However, you must also consider that if the case hardened surface is finish ground, the final carburized part surface might be harder than the carbonitrided surface if more than a minimal amount of stock is removed. The hardness of a carbonitrided case drops off much more quickly through its thickness than a carburized case, so you need to careful about how much stock is removed if the carbonitrided part is finish ground.
Lastly, if you currently have an unacceptable wear rate with parts that have a very high surface hardness, I don't think the best approach is slightly harder surfaces. To get the level of service life increase you desire (2X), you need to look at things like optimizing the relative surface geometries/textures, or applying surface coatings to reduce contact fretting.
RE: carburised vs carbonitrided - which has a better wear resistance
TVP: we know the environment these components are working in - regularly exposed to rocks, dirts etc and during downtime outdoor weather.
EDStainless: yes we are aware of the compressive failure. The proposed solution is to change from low carbon steel 10B21 to an alloy steel 5120! (which didn't go well with the objective "cost reduction")
Ttbuelna: The contact condition :bush is fixed, roller rotating. Wear is Bush OD and Roller ID. You are right regarding the wear pattern- we see wear on roller OD and ID and the wear on the bushing OD is localised. No finish ground on carbonitrided surface.
RE: carburised vs carbonitrided - which has a better wear resistance
He claimed 5120 carbonitrided case will have "better" wear resistance than carburised 5120 case because of the presence of micro hard carbonitrides or nitrides in the microstructures.
In 10B21, there is no nitride forming element, so there will no nitrides/carbonitrides in the case??
RE: carburised vs carbonitrided - which has a better wear resistance
That is what it would take to a different enough structure to really help.
Your other issue is corrosion, and that will be a bigger issue.
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Plymouth Tube
RE: carburised vs carbonitrided - which has a better wear resistance
RE: carburised vs carbonitrided - which has a better wear resistance
http://books.google.com/books?id=eIfcHJtv_kcC&...