strange metal

[Charlie,Participant @charlie18171]

I recently had a sort out of some steel rounds which i had not moved for a couple of years,Some of it was beginning to rust slightly, But three peices of about 8 inces long by inch and a half dia where bright as a new pin, But the end faces where very rusty,It is strongly magnetic, It is not stainless Not plated and not sheathed and it machines beautifully, So i cut bout 3 inches off,Faced off both ends and put it outside exposed to the rain and the fog,3days later the ends where totaly rusty but the outside dia was still bright,Anyone got any ideas on what type of metal this might be??,

[Charlie,Participant @charlie18171]

selective rust

[John ClaytonParticipant @johnclayton30974]

You sure its not just coated with a thin layer of varnish or similar, scratch the unrusted bit or machine the outside then test it .

[JohnFParticipant @johnf59703]

My guess is it is hydraulic ram material which is chrome plated on the outside.

John

[David LittlewoodParticipant @davidlittlewood51847]

While John is probably correct, it is worth mentioning that some types of stainless steel (ferritic) are magnetic.

David

[Russell EberhardtParticipant @russelleberhardt48058]

… and some stainless steel will develop rust spots. See some kitchen knives that have been in the dishwasher.

Russell;

[Ian S CParticipant @iansc]

Motor bike front forks, and car shock absorbers are another place chrome plated steel is used, good steel. Ian S C

[VersabossParticipant @versaboss]

And WHEN it is hydraulic ram or other (hard)chromed stuff, then it does mot machine beautifully! I had to throw away a couple of these nice rods. Only an angle grinder would scratch the outside. If you consider the usage, it has to be hard!!!

Sometimes the core part is softer, as it would be if case hardened before chroming.

Greetings, Hansrudolf

[Charlie,Participant @charlie18171]

Hi Chaps

Thanks for your interest and your input, But i remain convinced beyond reasonable doubt that the steel is not plated,But i am not in any way disapointed with it, I suspected that it might have been hard stuff,But now that i know it will machine easily with ordinary hss tools i am delighted with it but there is still a little gremlin in my mind telling me that somthing is not quite as it should be,

[Richard ParsonsParticipant @richardparsons61721]

There are some stainless steels which are not totally stainless. These were used for articled where strength and the ability to 'keep an edge' as important as being stain/rust resistant. The Swiss used them in their Victorionix Knives and the french in their Sabatier stuff.

Your treatment also indicates that the bars could have been Nickel plated. what it was used for God only knows. the best Chrome plate was always under plated with Nickel. Chrome is porous

Rdgs

Dick

[JohnFParticipant @johnf59703]

Hi Hansrudolf, I beg to differ regarding it being hard, I have machined this material many times–it is tough not hard, the chrome is there to prevent rusting and is fairly easy to cut through. Even light corrosion would quickly destroy the seals in a hydraulic cylinder. A ram does not need to be hard it needs resistance to bending but most of the stress in service is either is either compression or tensile.

Maybe your bars that you found to be hard were for some other special purpose?

Charlie, try a spark test on your grinder this will give an indication of the type of material–high / low carbon etc.

Regards John

[VersabossParticipant @versaboss]

Yes John, I also had shafts which could be machined quite easily. When I wrote 'has to be hard' then I meant the outside. I did not mean that the bars are hard up to the center like e.g. a piece of round HSS. Possibly there are different types of that stuff. One type I remember was wrapped, or rather shrunk in a thick blue plastic 'skin' with a Swedish type description. A product from Uddeholm perhaps?

Greetings, Hansrudolf

 

Edited By Versaboss on 17/03/2012 20:09:14

[DustyParticipant @dusty]

Charlie

Think about it logically, if the ends rust and the ouside of the bar is rust free then it must be coated with something.They are not two different materials. The most likely explanation is plating, laquers and other forms of (paint) will be damaged over the passage of time and rust will become evident. I have a clevis pin of some 1.5" dia which shows the same attributes as your metal, and yes it is plated.

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