Grade 5 vs Grade 23 Titanium Watches
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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 removes more of the trace interstitial elements, mainly oxygen and iron, which makes it slightly tougher, more ductile, and even more biocompatible, at a small cost in peak strength. On the wrist the two are practically indistinguishable in hardness, weight, and scratch resistance.
| Property | Grade 5 | Grade 23 |
|---|---|---|
| Full name | Ti-6Al-4V | Ti-6Al-4V ELI (extra low interstitials) |
| Purity | Standard interstitial levels | Lower oxygen and iron, higher purity |
| Toughness | High | Higher fracture toughness and ductility |
| Strength | Marginally higher peak strength | Slightly lower, more damage tolerant |
| Biocompatibility | Excellent | Medical-implant grade |
| On the wrist | Hard, scratch resistant, light | Effectively 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.
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. Treat a Grade 23 case as a slightly higher-purity Grade 5: excellent, and functionally the same on the wrist.
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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.