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ELI Grade 4 – Low Interstitial Titanium ELI Grade 4

Extra-Low Interstitial (ELI) Grade 4 titanium — a modified CP-Ti Grade 4 with controlled low oxygen, nitrogen, and carbon content for improved ductility, fracture toughness, and fatigue resistance in demanding aerospace and medical applications.

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Entity Definition

What is ELI Grade 4 Titanium?

ELI (Extra-Low Interstitial) Grade 4 is a modified version of standard CP-Ti Grade 4 with strictly controlled lower limits of interstitial elements — oxygen, nitrogen, carbon, and hydrogen. This controlled chemistry significantly improves ductility, fracture toughness, and fatigue properties while maintaining strength levels close to standard Grade 4.

Classification

Commercially Pure Titanium (Alpha Phase) — ELI Modification
UNS Number

UNS R50700 (modified)

Common Names

Grade 4 ELI CP-Ti Grade 4 ELI Extra-Low Interstitial Grade 4 ASTM F67 ELI Grade 4

Key Characteristics

  • Superior fracture toughness and fatigue resistance compared to standard Grade 4
  • Controlled low oxygen (≤0.15%) and nitrogen (≤0.03%) content
  • Enhanced ductility for improved formability and cold working
  • Excellent corrosion resistance — equivalent to standard CP grades
  • Preferred for critical implant applications requiring high reliability
Applicable Standards

Applicable Standards

ELI Grade 4 titanium conforms to the following international material standards:

ASTM F67 — Standard Specification for Unalloyed Titanium for Surgical Implant Applications
ISO 5832-2 — Implants for Surgery (ELI Grade)
ASTM B265 — Sheet, Strip, and Plate (when specified as ELI)
ASTM F136 (analogous ELI requirement approach)
Material Properties

Mechanical & Physical Properties

Typical room-temperature properties for ELI Grade 4 titanium (annealed condition):

Tensile Strength (min) 485 MPa (70 ksi)
Yield Strength 0.2% Offset (min) 380 MPa (55 ksi)
Elongation (min) 20%
Reduction of Area 35%
Fracture Toughness (KIC) > 80 MPa√m
Density 4.51 g/cm³ (0.163 lb/in³)
Elastic Modulus 105 GPa (15.2 × 10⁶ psi)
Melting Point 1,668°C (3,034°F)
Thermal Conductivity 17 W/(m·K)
Max Oxygen Content ≤ 0.15%
Processing Methods

Available Processing Methods

ELI Grade 4 titanium can be processed using the following manufacturing techniques:

Cold forming — Better than standard Grade 4 due to lower interstitial content
Hot forming — Recommended at 260–540°C (500–1,000°F)
CNC machining — Similar to standard Grade 4; requires sharp tools and adequate coolant
TIG welding — Good; ELI chemistry provides better weld ductility
Laser welding — Acceptable with inert gas shielding
Forging — At 870–980°C (1,600–1,800°F) with controlled cooling rate
Surface treatment — Anodizing, passivation, and polishing all applicable
Downstream Products

Typical Products & Components

ELI Grade 4 titanium is commonly fabricated into the following downstream products:

Orthopedic implants — trauma plates, bone screws, spinal fixation hardware
Dental implants and abutments
Surgical instruments requiring high toughness
Cryogenic components where low-temperature toughness is critical
Aerospace structural fittings requiring high reliability
High-performance marine hardware
Industries

Primary Industries

ELI Grade 4 titanium serves as a material of choice across these industries:

Medical — Orthopedic implants, dental implants, surgical instruments
Aerospace — Structural components requiring high fracture toughness
Cryogenic — Liquid gas storage and handling equipment
Defense — Military hardware requiring high reliability
Marine — Components subject to high cyclic loading
Alternative Materials

Alternative Materials

Depending on application requirements, ELI Grade 4 may be substituted by:

Standard Grade 4 (CP-Ti) — Lower cost but reduced ductility and toughness
Grade 23 (Ti-6Al-4V ELI) — Higher strength medical-grade alternative
Grade 5 (Ti-6Al-4V) — Higher strength but lower corrosion resistance in some environments
316LVM Stainless Steel — Lower cost but heavier and less biocompatible
Why BOZE CNC Ti

Why Choose Us for This Grade

BOZE CNC Ti is a medical-grade manufacturer of ELI Grade 4 components. Our ISO 13485 facility processes certified ASTM F67 ELI material with full traceability from certified mill sources.

Need ELI Grade 4 Components?

Our engineering team delivers precision-machined components in ELI Grade 4. Submit your RFQ for a competitive quote within 24–48 hours.

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About Boze Titanium Manufacturing Center

One Metal. One Focus. Infinite Precision.

Founded in 2011 in Baoji's Titanium Valley, BOZE Metal is dedicated exclusively to titanium — from raw material to precision engineering. AS9100D, ISO 13485 & ISO 9001 certified with 500+ clients across Aerospace, Medical & Motorsport industries, we deliver end-to-end precision titanium CNC machining with full material traceability from source to component.

Boze CNC Ti is the dedicated titanium manufacturing center of Baoji Boze Metal Products Co., Ltd.

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