Watch Case Materials Titanium Explained

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tempusmaximus
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Watch Case Materials Titanium Explained

Post by tempusmaximus »

Watch Case Materials Titanium Explained.
http://www.ablogtowatch.com/watch-case- ... -titanium/
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Re: Watch Case Materials Titanium Explained

Post by Robin CB »

Thanks TM, a very interesting article.

I understand the weight to strength ratio makes it lighter than steel of the same toughness, but can't see how, in general watch-making use, it relates to the tougher steels used by Bremont, Sinn, Damasko, etc?

Anyone any idea?
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Re: Watch Case Materials Titanium Explained

Post by ianblyth »

The steels used by Bremont, Sinn and Damasko are hardened and Vickers is used to measure them.

Bremont - http://www.bremont.com/about-us/technology
BREMONT B-EBE2000® WATCH CASE TREATMENT

All Bremont watches are treated for hardness with B-EBE2000® technology. During this special stage in the case production, the metal is heat-treated and diffused with carbon, then bombarded with electrons. The process dramatically increases the hardness and scratch resistance of the stainless steel. On the Vickers' scale of hardness, for example, B-EBE2000® produces a watch case with a value of 2000Hv - approximately seven times that of the normal stainless steel used for watch cases
Damasko - http://www.damaskousa.com/technology-stainless.asp
For our upcoming automatic pilot’s watch range (DA 36/46) we’ve chosen a highly corrosion resistant austenitic stainless steel alloy which can be fully hardened, leaving the surface with a key hardness of 1600 HV (Hardness Vickers). Just to give you an impression how hard this actually is: Titanium 180-210 HV, St. Steel AISI 316L 190-220 HV, Sapphire crystal 2000 HV.
But they also talk about
In order to compare our new steel with other commonly used stainless steels, we’ve decided to measure the PRE-factor (Pitting Resistance Equivalent).
Check the link.

Sinn - http://www.sinnwatch.com/sinn-watch-technologies.htm
Many Sinn watches are fitted with Tegimented cases produced in-house by Sinn's case making affiliated company in Glashutte, Germany.

Standard steel used by most watch companies has a hardness of between 200 and 240 HV (Hardness Vickers is a common scale used to measure material hardness). The Tegiment layer has a hardness of 1,200 Vickers which is five times harder than standard steel (and on some Sinn models even higher - up to nine times harder than standard steel).

The Tegiment layer is not a coating consisting of a foreign material, instead the steel itself that has been hardened using a special engineering process that creates a hardened barrier. The base material is a type of stainless steel also used for surgical implants, and the stainless steel resistance to corrosion is even further improved by the Tegiment hardening process.

The primary advantage to a Tegimented case is extreme resistance to scratches and other case abrasions.
So the treated steel is harder that Ti based on the Vickers measurement.

Although Dammsko say - Titanium 180-210 HV this page on Grade, 5 which the original article said was the most common, puts it at 349. http://asm.matweb.com/search/SpecificMa ... num=MTP641

The original article says
The hardness of titanium is lower than some steels, so it scratches easier than most steel.
But Titanium reacts with oxygen to create an oxide so the scratch gets "hidden" by the oxidation process. Most comments on scratching Ti mention this which means that although it may scratch it will "fade" and not be as noticeable as a similar scratch on steel.
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Re: Watch Case Materials Titanium Explained

Post by tempusmaximus »

It doesn't mention it in the article but Titanium is also non-magnetic.
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Re: Watch Case Materials Titanium Explained

Post by Robin CB »

Thanks Ian - a most comprehensive reply :thumbup:

In terms of Vickers it seems that the Bremont beats Damasko, which in turn beats Sinn.

Citizen are claiming a Vickers of 1200 for their Super Titanium which equals Sinn, http://www.citizenwatches.com.au/produc ... r-titanium

The other interesting aspect you point out (re Damasko) is this PRE, or corrosion resistance. Titanium is, I believe, supposed to be more corrosion resistant than normal steel, so I wonder how Damasko steel compares to it?

This is helpful, but doesn't give the PRE. http://www.keytometals.com/Article24.htm - I am struggling to find a watch related site that gives PRE (or PREN) for titanium

This site gives PRE for various watch steels, but does not give a figure for titanium, even though it compares the Vickers of IWC titanium https://watchotaku.atlassian.net/wiki/p ... ew/1638796

Of course, all of this is reasonably academic, given my active watch abusing days are behind me now, but it would be nice to know.
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