Titanium Grade 5 vs Grade 23: Frequently Asked Questions
Jan 19, 2026
Grade 5 and Grade 23 at a Glance
Titanium Grade 5 is the workhorse alpha-beta alloy Ti-6Al-4V, specified in ASTM B265, B348, and B861. Grade 23, also known as Ti-6Al-4V ELI, or extra low interstitial, is the medical and cryogenic variant with tighter limits on oxygen, iron, and other interstitial elements. Grade 23 is specified in ASTM F136 for implantable devices and in ASTM B348 and B265 for mill products.
Key Differences Between Grade 5 and Grade 23
| Property | Grade 5 (Ti-6Al-4V) | Grade 23 (Ti-6Al-4V ELI) |
|---|---|---|
| Oxygen limit | 0.20% max | 0.13% max |
| Iron limit | 0.40% max | 0.25% max |
| Hydrogen limit | 0.015% max | 0.0125% max |
| Minimum tensile strength | 895 MPa | 860 MPa |
| Minimum yield strength | 828 MPa | 795 MPa |
| Fracture toughness | Standard | Higher |
| Typical applications | Aerospace, industrial | Medical implants, cryogenic |
Frequently Asked Questions
What is the main difference between Grade 5 and Grade 23 titanium?
Grade 5 is the standard Ti-6Al-4V alloy, while Grade 23 is the extra low interstitial version with lower oxygen, iron, and hydrogen limits. The lower interstitial content gives Grade 23 improved ductility, fracture toughness, and damage tolerance.
Is Grade 23 better for medical implants?
Yes. Grade 23 is preferred for permanent implants because it meets ASTM F136, provides enhanced biocompatibility, and offers better fatigue resistance and fracture toughness under the cyclic loading experienced in the human body.
Which grade has higher strength?
Grade 5 has slightly higher minimum tensile and yield strength per the applicable ASTM standards. Grade 23 trades a small amount of strength for improved toughness and ductility.
Which grade is easier to machine?
Grade 23 is generally easier to machine because the lower interstitial content produces a slightly softer, more uniform microstructure, which reduces tool wear and improves dimensional control in precision machining.
How do the costs compare?
Grade 23 is usually more expensive than Grade 5 because of the tighter chemistry control, additional refining steps, and the certified mill production required for medical-grade material.
Can Grade 5 be used in place of Grade 23?
For structural and aerospace applications, Grade 5 is often suitable. For critical medical implant use, Grade 23 is recommended to satisfy biocompatibility and regulatory requirements such as ASTM F136.
What applications suit each grade best?
Grade 5 fits aerospace structures, fasteners, pressure vessels, and industrial components. Grade 23 suits surgical implants, dental components, cryogenic equipment, and other high-reliability applications requiring maximum fracture toughness.
Are Grade 5 and Grade 23 weldable?
Both grades can be welded with proper argon shielding and low-interstitial filler metal. Grade 23 filler is often used to weld Grade 5 joints that must retain maximum toughness.
