Ti-Grade 1, Pure Titanium Gr.1, Gr.2, Gr.3, Gr.4
May 14, 2026
What Are GR1, GR2, GR3, GR4 Titanium?
GR1 titanium, GR2, GR3, and GR4 are unalloyed (pure) titanium. GR1 titanium pipe and GR2 titanium pipe are classified as commercially pure grades.
The characteristics of titanium: light weight and high corrosion resistance. GR1 titanium tube is used in chemical industry, seawater service, marine structures, and biomedical materials.
Compared to iron, titanium has a smaller specific gravity but higher strength, offering a high strength-to-weight ratio. However, because the specific gravity is small (thermal capacity is small), GR1 titanium pipe heats up easily and cools quickly.
What Is the Difference Between GR1, GR2, GR3, and GR4?
The differences between Ti-Grade 1, GR2, GR3, and GR4 are only in the content of Oxygen (O), Iron (Fe), and Nitrogen (N). Mechanical properties such as GR1 titanium yield strength, tensile strength, and elongation increase or decrease with the increase or decrease of these elements. Grade 1 titanium hardness is the lowest among the four grades due to its minimal oxygen content.
Important: Oxygen increase in titanium raises brittleness. While oxygen strengthens the alpha phase, it also reduces elongation, toughness, and high-temperature stability. GR1 titanium chemical composition with 0.15-0.18% oxygen maximum provides the best ductility for forming operations.
Difference between pure titanium GR1 and GR2: Titanium CP1 has lower oxygen (0.15% max) than GR2 (0.20% max), giving GR1 titanium higher ductility and lower strength. For GR1 titanium for deep drawing applications, Grade 1 is preferred over Grade 2. Titanium grade 1 vs grade 2 selection should be based on whether formability (GR1) or slightly higher strength (GR2) is the priority. GR1 titanium forming/bending capabilities are superior to GR2 due to the lower oxygen content.
Chemical Composition Comparison (GR1 vs GR2 vs GR3 vs GR4)
| Grade | N (max) | C (max) | H (max) | Fe (max) | O (max) | Ti |
|---|---|---|---|---|---|---|
| GR1 | 0.03 | 0.08 | 0.013 | 0.20 | 0.15 | Remainder |
| GR2 | 0.03 | 0.08 | 0.013 | 0.25 | 0.20 | Remainder |
| GR3 | 0.05 | 0.08 | 0.013 | 0.30 | 0.30 | Remainder |
| GR4 | 0.05 | 0.08 | 0.013 | 0.50 | 0.40 | Remainder |
Mechanical Properties Comparison
| Grade | Tensile Strength (MPa) | Yield Strength (MPa min) | Elongation (% min) |
|---|---|---|---|
| GR1 | 270 – 410 | 165 | 27 |
| GR2 | 340 – 510 | 215 | 23 |
| GR3 | 480 – 620 | 345 | 18 |
| GR4 | 550 – 750 | 485 | 15 |
GR1 titanium yield strength is the lowest among pure titanium grades (165 MPa min), making it the most formable. Titanium grade 1 vs grade 2 selection should be based on the required strength vs ductility balance.
Titanium vs Other Metals – Physical Properties
| Property | Pure Ti | Pure Fe | Pure Al | Pure Cu | SUS304 |
|---|---|---|---|---|---|
| Melting point (°C) | 1668 | 1539 | 660 | 1084 | 1425 |
| Specific gravity (g/cm³) | 4.51 | 7.87 | 2.69 | 8.93 | 8.0 |
| Atomic number | 22 | 25 | 13 | 29 | – |
| Poisson's ratio | 0.34 | 0.31 | 0.33 | 0.34 | 0.29 |
| Young's modulus (GPa) | 106 | 192 | 69 | 116 | 199 |
| Thermal expansion coeff. | 8.4 | 12.0 | 23.0 | 16.8 | 17.3 |
| Thermal conductivity | 0.041 | 0.145 | 0.487 | 0.923 | 0.039 |
| Electrical conductivity (% Cu) | 3.1 | 18 | 4 | 100 | 15.7 |
| Specific heat | 0.12 | 0.11 | 0.23 | 0.09 | 0.12 |
| Crystal structure | HCP<883°C, BCC | BCC<830°C, FCC | FCC | FCC | Austenite |
Titanium grade 1 density is 4.51 g/cm³ – much lighter than steel (7.87) and copper (8.93), slightly heavier than aluminum (2.69). GR1 titanium pipe offers an excellent strength-to-weight ratio.
Applications of GR1 Titanium Pipe
| Industry | Typical Use |
|---|---|
| Chemical industry | GR1 titanium for chemical processing – piping, reactors, heat exchangers |
| Marine / Seawater | GR1 titanium heat exchanger tubes, seawater cooling lines |
| Marine structures | Offshore platform piping |
| Biomedical | Medical grade 1 titanium – ASTM F67 grade 1 implants |
Equivalent Standards for GR1 Titanium Tube
| Standard System | Designation |
|---|---|
| ASTM Pipe | B338 Grade 1 |
| ASTM Seamless Tube | B861 Grade 1 |
| UNS | R50250 |
| Werkstoff NR. | 3.7025 |
| JIS | H4600 Class 1 |
How to Weld and Form GR1 Titanium Pipe
| Parameter | Recommendation |
|---|---|
| How to weld GR1 titanium | GTAW (TIG) with ERTi-1 filler, pure argon shielding |
| GR1 titanium forming/bending | Excellent cold formability due to 27% elongation |
| GR1 titanium machinability | Use sharp carbide tools, low speeds, abundant coolant |
| GR1 titanium for deep drawing | Preferred grade for complex drawn parts |
FAQ
Q1: What is the difference between GR1 and GR2 titanium pipe?
A: The difference between pure titanium GR1 and GR2 is primarily oxygen content. GR1 titanium pipe has 0.15-0.18% oxygen maximum, while GR2 has 0.20-0.25% oxygen maximum. This gives GR1 titanium higher ductility (27% vs 23% elongation) and lower yield strength (165 MPa vs 215 MPa).
Q2: What is the UNS number for ASTM B861 grade 1 titanium tube?
A: The UNS number for ASTM B861 grade 1 titanium tube is R50250. ASTM B338 grade 1 titanium pipe also uses UNS R50250. The German equivalent is Werkstoff NR. 3.7025.
Q3: What is the density of titanium grade 1 pipe compared to stainless steel?
A: Titanium grade 1 density is 4.51 g/cm³. SUS304 stainless steel density is 8.0 g/cm³. GR1 titanium pipe weighs approximately 44% less than same-dimension stainless steel pipe.
Q4: What is the maximum oxygen content for GR1 titanium tube?
A: The maximum oxygen content for GR1 titanium tube per this source is 0.15%. Other standards (ASTM B861) specify 0.18% maximum. Buyers should confirm the required GR1 titanium chemical composition with their GR1 titanium tube suppliers based on the specific standard revision.
Q5: Can GR1 titanium pipe be used for biomedical applications?
A: Yes, medical grade 1 titanium conforming to ASTM F67 grade 1 is used for surgical implants and biomedical devices. GR1 titanium is biocompatible and offers excellent corrosion resistance in body fluids.
Q6: What is the elongation percentage of GR1 titanium tube?
A: The minimum elongation of GR1 titanium tube is 27% per this source (higher than the typical 24% in ASTM standards). This high ductility makes GR1 titanium for deep drawing and GR1 titanium forming/bending excellent choices for complex shapes.
Q7: What is the melting point of pure titanium?
A: The melting point of pure titanium (including GR1 titanium) is 1668°C. This is higher than iron (1539°C), copper (1084°C), and SUS304 (1425°C). However, GR1 titanium pipe operating temperature is limited to approximately 300-400°C due to oxidation.
Q8: Is GR1 titanium pipe suitable for seawater applications?
A: Yes, GR1 titanium pipe is highly suitable for seawater applications. The article states titanium is used in seawater and marine structures. GR1 titanium tube offers excellent corrosion resistance in chloride environments.
Inspection
| Test | Purpose |
|---|---|
| Chemical analysis | Verify GR1 titanium chemical composition (N, C, H, Fe, O) |
| Tensile testing | Confirm GR1 titanium yield strength, tensile strength, elongation |
| Hydrostatic test | Pressure integrity of GR1 titanium pipe |
| Ultrasonic testing | Detect internal flaws in GR1 titanium tube |
| Eddy current testing | Surface defect detection |
| Visual and dimensional | Check OD, wall thickness, length, surface finish |
Packaging
Plastic end caps on both ends of each GR1 titanium tube
Bundled with steel straps
Wooden crates or pallets for export
Labeled with grade (GR1), standard (ASTM B338/B861), heat number, dimensions
Factory Equipment
VAR furnace for ingot melting
Extrusion press for pipe hollows
Cold pilger mill for tube reduction
Annealing furnace
Pickling line
Ultrasonic and eddy current testers
Hydrostatic tester
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