Overview
Grade 7 Titanium, also known as Ti-0.15Pd Titanium, is a commercially pure titanium alloy enhanced with approximately 0.12–0.25% palladium (Pd). This small addition of palladium dramatically improves corrosion resistance in highly reducing and aggressive chemical environments while maintaining the excellent weldability, formability, and toughness of commercially pure titanium.
Grade 7 is considered one of the most corrosion-resistant titanium grades available and is commonly used in chemical processing, desalination, offshore, pharmaceutical, and pollution-control applications.
Grade 7 titanium is widely used in:
- Chemical Processing Equipment
- Desalination Plants
- Offshore Systems
- Heat Exchangers
- Pharmaceutical Equipment
- Acid Handling Systems
- Pollution Control Equipment
- Marine Components
Because of its exceptional corrosion resistance, Grade 7 is often selected when Grade 2 titanium is insufficient for highly aggressive environments.
Material Specification
| Property | Value |
|---|---|
| Material Designation | Grade 7 Titanium |
| Alloy Name | Ti-0.15Pd |
| UNS Number | R52400 |
| ASTM Standard | ASTM B265 / ASTM B348 / ASTM B381 |
| Material Family | Palladium-Stabilized Commercially Pure Titanium |
| Density | 4.51 g/cm³ |
| Magnetic Property | Non-Magnetic |
| Typical Supply Condition | Annealed |
| Standard Forms | Sheet, Plate, Bar, Rod, Tube, Pipe, Wire |
Chemical Composition
| Element | Content (%) |
|---|---|
| Titanium (Ti) | Balance |
| Palladium (Pd) | 0.12–0.25 |
| Oxygen (O) | ≤0.25 |
| Iron (Fe) | ≤0.30 |
| Carbon (C) | ≤0.08 |
| Nitrogen (N) | ≤0.03 |
| Hydrogen (H) | ≤0.015 |
The palladium addition significantly improves resistance to crevice corrosion and reducing acid environments.
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥345 MPa |
| Yield Strength | ≥275 MPa |
| Elongation | ≥20% |
| Hardness | 130–180 HB |
| Elastic Modulus | 105 GPa |
Typical Mechanical Performance
| Property | Value |
|---|---|
| Fatigue Resistance | Good |
| Impact Toughness | Excellent |
| Ductility | Excellent |
| Formability | Excellent |
Mechanical properties are very similar to Grade 2 titanium.
Physical Properties
| Property | Value |
|---|---|
| Density | 4.51 g/cm³ |
| Melting Point | 1660–1670°C |
| Thermal Conductivity | 16.3 W/m·K |
| Electrical Conductivity | 3% IACS |
| Electrical Resistivity | 0.56 μΩ·m |
| Thermal Expansion Coefficient | 8.6 × 10⁻⁶/K |
| Specific Heat Capacity | 523 J/kg·K |
Strength-to-Weight Ratio
| Material | Density (g/cm³) | Tensile Strength |
|---|---|---|
| Grade 7 Titanium | 4.51 | 345 MPa |
| Grade 2 Titanium | 4.51 | 345 MPa |
| Grade 1 Titanium | 4.51 | 240 MPa |
| 316L Stainless Steel | 8.00 | 485 MPa |
Grade 7 offers the same lightweight characteristics as Grade 2 while providing superior corrosion resistance.
Corrosion Resistance
| Environment | Performance |
|---|---|
| Fresh Water | Excellent |
| Salt Water | Excellent |
| Marine Atmosphere | Excellent |
| Chloride Solutions | Outstanding |
| Reducing Acids | Outstanding |
| Chemical Processing | Outstanding |
Grade 7 provides significantly better corrosion resistance than Grade 2 in reducing acid environments such as sulfuric acid, phosphoric acid, and chloride-rich systems.
Recommended surface treatments:
- Pickling
- Passivation
- Electropolishing
- Anodizing
- Chemical Cleaning
Corrosion Resistance Comparison
| Material | Corrosion Resistance |
|---|---|
| Grade 7 Titanium | Outstanding |
| Grade 2 Titanium | Excellent |
| Grade 5 Titanium | Excellent |
| Hastelloy C276 | Outstanding |
| 316L Stainless Steel | Good |
Grade 7 is often considered the most corrosion-resistant titanium alloy in commercial service.
Weldability
| Welding Process | Rating |
|---|---|
| TIG Welding | Outstanding |
| MIG Welding | Excellent |
| Resistance Welding | Excellent |
| Laser Welding | Excellent |
Grade 7 maintains excellent weldability similar to commercially pure titanium grades.
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Moderate |
| CNC Milling | Moderate |
| Drilling | Moderate |
| Grinding | Good |
| Forming | Excellent |
Machinability Comparison
| Material | Machinability |
|---|---|
| Aluminum 6061 | Excellent |
| Stainless Steel 304 | Moderate |
| Grade 7 Titanium | Moderate |
| Grade 5 Titanium | Difficult |
Machining characteristics are similar to Grade 2 titanium.
Heat Treatment
Stress Relief
| Parameter | Value |
|---|---|
| Temperature | 480–650°C |
| Cooling Method | Air Cool |
Annealing
| Parameter | Value |
|---|---|
| Temperature | 650–760°C |
| Cooling Method | Air Cool |
Heat Treatability
| Property | Performance |
|---|---|
| Heat Treat Hardening | No |
| Annealing Response | Excellent |
| Cold Work Strengthening | Limited |
Grade 7 is not heat treatable for strength enhancement.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM (USA) | Grade 7 |
| UNS | R52400 |
| DIN (Germany) | 3.7235 |
| EN (Europe) | Ti-Pd Alloy |
| ISO | Titanium Grade 7 |
| JIS (Japan) | Ti-0.15Pd |
| GB/T (China) | TA9 |
Available Forms
| Product Type | Availability |
|---|---|
| Sheet | Yes |
| Plate | Yes |
| Round Bar | Yes |
| Flat Bar | Yes |
| Tube | Yes |
| Pipe | Yes |
| Wire | Yes |
| Forgings | Yes |
Typical Applications
Chemical Processing Industry
- Acid Storage Tanks
- Heat Exchangers
- Reactor Systems
- Chemical Piping
Desalination Industry
- Seawater Systems
- Evaporators
- Condensers
- Water Treatment Equipment
Marine Industry
- Offshore Platforms
- Seawater Cooling Systems
- Marine Fasteners
- Corrosion-Resistant Components
Pharmaceutical Industry
- Process Equipment
- Sterile Systems
- High-Purity Piping
- Storage Vessels
Environmental Industry
- Scrubbers
- Pollution Control Systems
- Waste Treatment Equipment
Energy Industry
- Power Plant Heat Exchangers
- Flue Gas Systems
- Corrosion-Resistant Equipment
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Machining | Good |
| Forming | Excellent |
| Deep Drawing | Excellent |
| Welding | Outstanding |
| Anodizing | Excellent |
| Polishing | Excellent |
Advantages
Outstanding Corrosion Resistance
Superior performance in reducing acid and chloride environments.
Excellent Weldability
Suitable for complex welded fabrications.
Lightweight
Approximately 45% lighter than stainless steel.
Excellent Formability
Can be formed using conventional titanium fabrication methods.
Long Service Life
Exceptional durability in aggressive industrial environments.
Biocompatible
Suitable for medical and pharmaceutical applications.
Limitations
Higher Cost Than Grade 2
Palladium addition significantly increases material cost.
Lower Strength Than Grade 5
Not intended for high-load structural applications.
Limited Availability
Less commonly stocked than Grade 2 titanium.
Poor Thermal Conductivity
Similar to other titanium alloys.
Comparison with Other Titanium Grades
| Property | Grade 7 | Grade 2 | Grade 5 | Grade 1 |
|---|---|---|---|---|
| Corrosion Resistance | Highest | Excellent | Excellent | Excellent |
| Strength | Moderate | Moderate | High | Lower |
| Weldability | Outstanding | Outstanding | Good | Outstanding |
| Formability | Excellent | Excellent | Moderate | Outstanding |
| Cost | Highest | Moderate | High | Moderate |
Comparison with Common Corrosion-Resistant Materials
| Material | Corrosion Resistance | Strength | Weight |
|---|---|---|---|
| Grade 7 Titanium | Outstanding | Moderate | Light |
| Grade 2 Titanium | Excellent | Moderate | Light |
| Hastelloy C276 | Outstanding | High | Heavy |
| 316L Stainless Steel | Good | Moderate | Heavy |
Available Surface Finishes
Raw Finishes
- Mill Finish
- Annealed Finish
- Pickled Finish
Functional Finishes
- Precision Machined Finish
- Polished Finish
- Brushed Finish
Specialty Finishes
- Electropolished Finish
- Anodized Finish
- Pharmaceutical Grade Finish
Frequently Asked Questions (FAQ)
What is Grade 7 titanium?
Grade 7 is a palladium-enhanced commercially pure titanium alloy designed for superior corrosion resistance.
What is Grade 7 titanium used for?
Typical applications include:
- Chemical Processing Equipment
- Heat Exchangers
- Desalination Systems
- Pharmaceutical Equipment
- Marine Components
What is the equivalent material to Grade 7 titanium?
Common equivalents include:
- Ti-0.15Pd
- UNS R52400
- DIN 3.7235
- TA9
What is the difference between Grade 2 and Grade 7 titanium?
| Property | Grade 2 | Grade 7 |
|---|---|---|
| Strength | Similar | Similar |
| Corrosion Resistance | Excellent | Superior |
| Cost | Lower | Higher |
| Acid Resistance | Good | Outstanding |
Is Grade 7 titanium corrosion resistant?
Yes. It is one of the most corrosion-resistant titanium grades available.
Can Grade 7 titanium be welded?
Yes. Grade 7 offers excellent weldability and fabrication characteristics.
Why choose Grade 7 titanium?
Because it combines:
- Outstanding Corrosion Resistance
- Excellent Weldability
- Lightweight Performance
- Long Service Life
- Chemical Processing Reliability
Is Grade 7 titanium suitable for acid service?
Yes. Grade 7 is specifically designed for aggressive acid and chloride environments.
Does GCNOV provide custom manufacturing services for Grade 7 titanium?
Yes. GCNOV provides:
- CNC Machining
- Titanium Fabrication
- Precision Welding
- Chemical Processing Components
- Surface Finishing
- Prototype Development
- Low-Volume Production
- Mass Production