— Properties, Applications, Corrosion Resistance, Price & Technical Insights
Titanium is widely valued in aerospace, chemical processing, medical, and marine sectors due to its high strength-to-weight ratio, corrosion resistance, and biocompatibility. Among the various grades defined by ASTM B348, Grade 1 through Grade 4 represent commercially pure titanium (CP-Ti), while Grade 7 is a palladium-enhanced alloy designed for extreme corrosion resistance.
This article provides a detailed multi-dimensional comparison of GR1, GR2, GR3, GR4, and GR7 — covering composition, mechanical and physical properties, corrosion behavior, processability, pricing, and applications.
📌 1. Material Type & Composition Overview
| Grade | Type | Main Alloying Elements | Pd Added | Characteristics |
|---|---|---|---|---|
| GR1 | CP-Ti (Softest) | Ti ≥ 99.5% | ❌ | Excellent ductility, lowest strength |
| GR2 | Standard CP-Ti | Ti ≥ 99.2% | ❌ | Balanced strength and formability |
| GR3 | High-strength CP-Ti | Ti ≥ 99.0% | ❌ | Higher strength, reduced ductility |
| GR4 | Strongest CP-Ti | Ti ≥ 98.8% | ❌ | Highest strength, limited formability |
| GR7 | Modified CP-Ti | Ti + 0.12–0.25% Pd | ✅ | Superior corrosion resistance in harsh media |
⚙️ 2. Mechanical & Physical Properties (Annealed Condition)
| Property | GR1 | GR2 | GR3 | GR4 | GR7 |
| Tensile Strength (MPa) | ≥ 240 | ≥ 345 | ≥ 450 | ≥ 550 | ≥ 345 |
| Yield Strength (MPa) | ≥ 170 | ≥ 275 | ≥ 380 | ≥ 483 | ≥ 275 |
| Elongation (%) | ≥ 24 | ≥ 20 | ≥ 18 | ≥ 15 | ≥ 20 |
| Hardness (HB) | ~70 | ~80 | ~100 | ~120 | ~80 |
| Elastic Modulus (GPa) | ~105 | ~105 | ~110 | ~110 | ~105 |
| Density (g/cm³) | 4.51 | 4.51 | 4.51 | 4.51 | 4.51 |
🌊 3. Corrosion Resistance Profile
Grade 7 offers significantly enhanced resistance in environments with chlorides due to its palladium content. It surpasses all other CP-Ti grades in reducing acids and oxidizing chloride media.
| Environment | GR1 | GR2 | GR3 | GR4 | GR7 |
| Oxidizing Acids | ★★★★☆ | ★★★★☆ | ★★★★☆ | ★★★★☆ | ★★★★★ |
| Reducing Acids (e.g., HCl) | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★★★★ |
| Wet Chlorine | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★★★★ |
| Sodium Hypochlorite | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★☆☆☆ | ★★★★★ |
| Seawater | ★★★★☆ | ★★★★☆ | ★★★★☆ | ★★★★☆ | ★★★★★ |
GR7 is the only grade among CP titanium that offers long-term reliability in chloride-heavy and acidic environments.
🛠️ 4. Processing & Weldability
| Attribute | GR1 | GR2 | GR3 | GR4 | GR7 |
| Cold Formability | Excellent | Very Good | Good | Fair | Very Good |
| Weldability | Excellent | Good | Good | Moderate | Excellent |
| Machinability | Moderate | Moderate | Poor | Poor | Moderate |
| Deep Drawing | Excellent | Very Good | Fair | Limited | Very Good |
💰 5. Price & Supply Overview (2024 Estimate)
| Grade | Price Range (RMB/kg) | Notes |
| GR1 | ¥140–180 | High purity, easy processing |
| GR2 | ¥160–220 | Balanced cost-performance |
| GR3 | ¥180–240 | Strength-focused, limited supply |
| GR4 | ¥200–260 | High load-bearing applications |
| GR7 | ¥180–300 | Pd content affects pricing significantly |
🧩 6. Recommended Applications
| Application Area | Recommended Grade |
| Medical Devices | GR1, GR2 |
| Heat Exchangers | GR2, GR3 |
| Pressure Vessels | GR3, GR4 |
| General Chemical Equipment | GR2–GR4 |
| Chloride/Acidic Environments | GR7 only |
| Electroplating Fixtures | GR7 preferred, GR2 for mild duty |
✅ 7. Final Recommendation
- For general industrial needs → GR2 is the most cost-effective
- For higher strength but not aggressive media → GR3 or GR4
- For strongly corrosive conditions like hydrochloric acid or wet chlorine → GR7 is essential
🏢 About NiTiCu Metal Co., Ltd
NiTiCu Metal Co., Ltd is a leading manufacturer and global supplier of titanium and specialty alloy products. We stock and supply GR1 through GR4 and GR7 titanium rods, plates, wires, and custom-machined components, along with MTC, CO documentation, and export support.
📍 Address: China Titanium Valley, High-Tech Zone, Baoji, Shaanxi, China
🌐 Website: www.niticu.com
📧 Email: sales@niticu.com
📞 Tel/WeChat/WhatsApp: +86 13335373172
