Gold train wheels....mechanically advantageous or simply aesthetically pleasing?

[John Matthews]

pure gold, being extremely ductile, doesn't work-harden

Graham I believe it does.

This is my understanding from university days in the 1960s!

Work hardening is a process by which which permanent deformation takes place by the formation of dislocations - i.e. the material suffers strain hardening, permanent deformation. As the number of dislocations increase they interact and thereby restricting their movement. It is that restriction which 'hardens' the material. The rate & degree of hardening is a function of the rate at which the dislocations are formed and how they interact - which varies from material to material depending on atomic structure and the state of the material at the start of the process.

John

 

[gmorse]

Hi John,

When gold leaf, which is extremely thin at between 1 and 4 microns, is produced by beating or rolling it out, does it need to be periodically annealed? I don't know the answer to this but I suspect that it doesn't.

Regards,

Graham

 

[John Matthews]

Graham - no I believe annealing is not required.

The lack of a surface oxide layer is said to allow the dislocations to escape when they migrate to the surface. This means that although there is strain hardening it is limited by surface dislocation escape, so hardening occurs, but does not lead to failure.

John

edit if you calculate the % hardening of the Au alloys in the table you will see that they all have significant % increases

 

[gmorse]

Hi John,

Yes, as I've found from practical experience, gold alloys do demonstrate hardening but pure gold doesn't appear to in any measurable degree. I would guess that producing gold leaf of different colours which involves various small alloying additives does require some sort of heat treatment.

Regards,

Graham

 

[novicetimekeeper]

Pure gold is said to never need annealing, which rather suggests it never work hardens.

 

[Bernhard J.]

See the table above, which I had posted. Pure AU shows up to 3-fold the HV hardness upon work hardening. Here it is again.

 

[John Matthews]

As Bernard is implying 99.99% is effectively pure gold. Vickers hardness increases by 268%

John

 

[Dr. Jon]

What is the source of the information on Glashutte escapement material?

 

[miguel angel cladera]

What is the source of the information on Glashutte escapement material?

Sorry to be more precise, but I don't have much time right now. Here you will find the necessary information.

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[Bernhard J.]

What is the source of the information on Glashutte escapement material?

In Miguels link specifically in this article " Bester Anker und Art des Ankerganges für Präzisionsuhren" stating that the components are made of hammered gold.

With respect to this being as hard as steel, I do not recall where I have read it, but a quick search gives this reference, wherein this is stated.

Uhrentechnik: Anker (Glashütter)

Homepage

uhrentechnik.vyskocil.de

Best regards, Bernhard