Damasko has their own unique way of hardening steel: some are hardened all the way through, others are surface-hardened (like tegiment).

 

Citizen also have a variety of hardening techniques that they refer to as "Duratect". Typically they use these to surface harden titanium, but occasionally they'll do hardened steel as well.

 

Tegiment actually hardens the metal through chemical means (typically infusing carbon or nitrogen). DiaShield (Seiko) and Duratect (Citizen) are coatings applied atop metal (like DLC).

 

Damasko utilizes 2 different hardening techniques. Their Ice hardened cases are thru-hardened, but to a lower hardness than Tegiment (roughly half). Their submarine steel receives a treatment similar to Tegiment.

Archimede features some models with surface treatments comparable to Tegiment

Bremont uses hardened cases with similar hardness to Tegiment on all watches

 

^This

 

I like how Sinn dresses up case hardening by calling it tegimented.

 

Proprietary process to Sinn. Its not "dressing it up" but calling it by its technical name for the unique process which reportedly is a variation on the original process developed by Herr Prof. Dr. Kolster. They used to "ice harden" initially but improved the process and stopped using the older technology.

 

Discussion about a year ago:

Watches with Hardened Watch Cases: Trying to Compile a List!

BTW-Sorry-don't know how to link to an old discussion-help on that front would be appreciated. Thx.

 

Watches with Hardened Watch Cases: Trying to Compile a List!

Watches with hardened cases (and sometimes bracelets) have really caught my interest lately, and I would like to compile a list of watches that use various hardening techniques. I found some similar threads, but for the most part they seemed fairly old and outdated. For readability I am going to...

www.watchuseek.com

 

Dekla has hardened cases too, I believe.

Apart from that, a lot of microbrands seem to be coating their metals with something to make it more resistant to scratches - RZE (Reise), Zelos, Traska, Iridium etc.

 

Thanks i found it via google search

 

„Tegimented" is just another word for „kolsterized" = surface hardened. Kolsterising is a thermo-chemical process which basically is a diffusion of carbon into the surface of a stainless steel item at low temperatures. A lot of manufacturers use this process or similar ones using inventive notations. The inventor of this process was Prof. Dr. Kolster. Kolsterising® and other Bodycote S³P treatments have been successfully implemented for over 20 years in a wide variety of industries. For more info I suggest to look into www.bodycote.com.

Damasko uses two case hardening processes:

• Ice-hardening for martensitic stainless steel cases
• Surface hardening (DS 30, DSub 1,2,3 and DSub50, DC7x) for austenitic stainless steel

 

Traska uses a hardening technique that achieves the same hardness as Sinn.

 

No matter what it is "called" it really helps with maintaining a tough and scratch resistant surface.

 

Whatever Bremont does to their cases works pretty well. I recently sent my 8 year old in for service and it had a couple minor dings along the edges, but zero scratches. At service, they replace the entire top bezel since it cannot be polished due to the hardness.

 

Yeah. The hardened cases from Damasko are fantastic. Couldn't believe their claims either. Until I had a Damasko DA 38 that I used as a daily beater for 5 years.

This is the day before I sold it this year. Bought it 2015. Wore it daily. Not a single scratch or dent.

 

From what I gather, the issue is really one of comparing apples and oranges. Sinn Tegimented steel has a hardness rating of around 1200 Vickers / 72 Rockwell (from the Sinn website). But the process achieves that hardness over a thin 20-30 micron layer on the surface of the metal.

Ice/liquid nitrogen-hardened Damasko steel cases are in the 800 Vickers / 64-62 Rockwell range for hardness. But this process treats the entire metal right through, as opposed to a super hard exterior layer.

Which one ultimately is better from a scratch resistance standpoint, I really don't know. Damasko claims that just hardening the layer leads to an "eggshell" effect, where the surface may not scratch per se, but enough outside pressure may still dent the metal because the underlying steel is not as hard as the surface. Damasko says that because all their metal is ice hardened, this is not a problem with their cases. I would expect though that in 99% of regular use cases, simple day-to-day scratch events are covered adequately by both methods.

One thing to note is that for Sinn, you have to look for the watches that offer tegimented steel cases. Not all watches in the Sinn lineup are case tegimented. For some models, it's only done for the bezel (for example).

I believe all Damasko watches use ice hardened steel. And the steel is used not only for the case and bezel but also the crown and any pushers.

 

….I believe all Damasko watches use ice hardened steel. And the steel is used not only for the case and bezel but also the crown and any pushers.

Sorry to say, the DS30, DK3x, DSub, DC7x are not ice-hardened, for more info see Damasko Uhren Forum and/or website.

 

A long-term friend of mine was an engineer, working with cryogenic treatments of metals…

Not trying to get into anything, but it’s very idiosyncratic stuff. From what I’ve gathered, it varies considerably from product to product, even within the same company.

(Kinda like large scale cooking. Some recipes can be multiplied 20 fold, without issue... Others go completely off into the weeds.)

 

I'm guessing at the level of metallurgy and quantity involved in watch cases (meaning relatively small batch, small size), the QC on the metal is easier to manage. I'm pretty sure all watchmakers that have their own foundries throwaway or meltdown (whatever) a number of cases that do not pass QC.

 

Traska claims their coating brings their case and bracelets to 1200 vickers as well. I believe them. Not a scratch on either of mine and I wear them hard. Same with my RZE watch. On the other hand, my Citizen watch claims to have a hardened coating on it and it is marked and dinged up to no end. Never owned a Sinn.