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Grade 5 vs Grade 23 Titanium Watches

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Apiar Gen1.1 MR^2
Apiar Gen1.1 MR^2 Image: Apiar

Grade 23 is the higher-purity sibling of Grade 5. Both are Ti-6Al-4V; Grade 23 is the ELI, or extra-low-interstitial, version. Here is what that means on a watch.

The short version

Chemically they are the same alloy. Grade 23 sets tighter limits on the interstitial elements, above all oxygen, and on iron, which makes it slightly tougher and more biocompatible at a small cost in peak strength. On the wrist the two cannot be told apart, since they scratch and weigh the same.

PropertyGrade 5Grade 23
Full nameTi-6Al-4VTi-6Al-4V ELI (extra low interstitials)
PurityStandard interstitial levelsLower oxygen and iron, higher purity
ToughnessHighHigher fracture toughness and ductility
StrengthMarginally higher peak strengthSlightly lower, more damage tolerant
BiocompatibilityExcellentMedical-implant grade
On the wristHard, scratch resistant, lightEffectively identical

Same alloy, cleaner recipe

The ELI in Grade 23 stands for extra low interstitials. Reducing the dissolved oxygen and iron makes the metal tougher and more forgiving of stress, which is why Grade 23 is the choice for medical implants. The everyday hardness and light weight that define Grade 5 carry straight over.

How rare Grade 23 actually is

In the catalogGrade 5Grade 23
References614 (31%)20 (1%)
Brands using it1734
Median price$7,869$17,800
Median case size42 mm40.15 mm
References with a published weight1397

This is the part worth knowing before you spend time on the comparison. Grade 23 is 20 references from 4 brands in this guide, against 614 Grade 5 references from 173 brands. It is not a choice most buyers will ever face, and where it appears it is at the top of the market: a median of $17,800 against $7,869 for Grade 5.

So treat this page as a spec-sheet decoder rather than a buying decision. If a maker prints Grade 23 or ELI, you now know what it means. It is very unlikely to be the reason you pick one watch over another.

Why a brand chooses Grade 23

For a watch the appeal is purity and skin compatibility rather than a difference you can feel. Cartier, for instance, uses what it calls Grade 5 ELI, which corresponds to Grade 23.

Grade 5 titanium in the catalog
Tudor Pelagos FXD GMTTudorPelagos FXD GMT$5,47542.0 mm12.75 mm thick81 gDiverStraum Jan Mayen TitaniumStraumJan Mayen Titanium$2,50038.7 mm11.5 mm thick82 gIntegrated braceletFormex Aria Manufacture Chronometer (Titanium)FormexAria Manufacture Chronometer (Titanium)$7,90040.0 mm6.9 mm thick78 gIntegrated braceletRolex Yacht-Master 42 (RLX Titanium)RolexYacht-Master 42 (RLX Titanium)$16,05042.0 mmDiverPanerai Submersible GMT Luna Rossa Titanio 42mmPaneraiSubmersible GMT Luna Rossa Titanio 42mm$13,10042.0 mmDiverOmega Seamaster Planet Ocean Ultra Deep 6000M (Titanium)OmegaSeamaster Planet Ocean Ultra Deep 6000M (Titanium)$15,30045.5 mm18.12 mm thick123 gDiver
Grade 23 titanium in the catalog
Blancpain Fifty Fathoms Bathyscaphe TitaniumBlancpainFifty Fathoms Bathyscaphe Titanium$15,10043.0 mm13.45 mm thickDiverCartier Santos de Cartier Large (Titanium)CartierSantos de Cartier Large (Titanium)$11,50039.8 mm9.38 mm thickIntegrated braceletLaventure Marine Type 3LaventureMarine Type 3$5,04638.0 mm11.2 mm thickDiverApiar Gen1.1 MR^2ApiarGen1.1 MR^2$3,51939.0 mm9.2 mm thick40 gDressBlancpain Fifty Fathoms Automatique 42mm TitaniumBlancpainFifty Fathoms Automatique 42mm Titanium$22,40042.3 mm14.3 mm thickDiverBlancpain Fifty Fathoms Tech Gombessa TitaniumBlancpainFifty Fathoms Tech Gombessa Titanium$35,00047.0 mm14.81 mm thickDiver

Sources

Counts, medians and shares from the catalog are computed by the guide itself, as its methodology describes. The material properties, maker statements and dates on this page were checked against these sources.

  1. NeoNickel, Ti-6Al-4V (Grade 5 Titanium): properties
  2. Standard Titanium Co., Grade 23 6Al-4V ELI
  3. Titanium Industries, ASTM F136: Ti-6Al-4V ELI for surgical implants
  4. Titanium Field Guide, Methodology

Frequently asked questions

Is Grade 23 titanium better than Grade 5?

They are the same alloy. Grade 23 is the higher-purity ELI (extra low interstitials) version of Grade 5, marginally tougher and more biocompatible with slightly lower peak strength. For a watch the practical difference is negligible.

What is Ti-6Al-4V ELI?

ELI stands for extra low interstitials: the same Grade 5 alloy refined to contain less oxygen and iron, which improves toughness and biocompatibility. Cartier markets its version as Grade 5 ELI, which corresponds to Grade 23.