GR1 3.7025 / UNS R50250 Titanium Pipe
May 18, 2026
(3.7025 / UNS R50250) is the first on the list of commercially pure titanium grades. GR1 titanium pipe is an unalloyed titanium with the highest purity out of all ASTM grades. Although it is the softest titanium showing the lowest strength, this grade compensates with the highest ductility at room temperature.
Standards: ASTM B338 (Pipe), ASTM B861 (Seamless Tube) | UNS R50250 | W. Nr. 3.7025
Key Properties of GR1 Titanium Pipe
| Property | Description |
|---|---|
| Formability | Greatest formability compared to other titanium grades |
| Corrosion immunity | Excellent corrosion resistance |
| Impact toughness | High impact toughness |
| Environmental resistance | Resistant to highly oxidizing and reducing environments, also when exposed to chlorides |
| Temperature capability (continuous) | Up to 800°F (425°C) |
| Temperature capability (intermittent) | Up to 1000°F (540°C) |
| Low temperature properties | Good impact properties at low temperatures |
| Fabrication | Easily welded, cold- and hot-machined, and cast |
GR1 titanium pipe is popular in constant operations applications where temperatures reach up to 425°C, and in intermittent working conditions where temperatures reach up to 540°C. It also exhibits good impact properties at low temperatures.
Weight Savings Advantage
| Benefit | Value |
|---|---|
| Weight reduction | Use of GR1 titanium may reduce the mass of an entire structure by up to 40% |
Titanium grade 1 density of 4.51 g/cm³ enables significant weight savings compared to steel structures.
Chemical Composition of GR1 Titanium Pipe
GR1 titanium chemical composition limits:
| Element | Max % |
|---|---|
| Fe | 0.20 |
| O | 0.18 |
| N | 0.03 |
| C | 0.08 |
| H | 0.015 |
Physical Properties of GR1 Titanium Tube
| Property | Value |
|---|---|
| Tensile strength | min. 240 N/mm² |
| GR1 titanium yield strength (0.2%) | min. 138 N/mm² |
| Titanium grade 1 density | 4.51 g/cm³ |
| Elongation | 24% |
| Specific heat | 520 J/g°C |
| Elastic modulus | 105 kN/mm² |
| Grade 1 titanium hardness (HV) | 115 |
Heat Treatment of GR1 Titanium Pipe
| Treatment | Temperature Range |
|---|---|
| Soft annealing | 600°C – 700°C |
| Stress relief heat treatment | 450°C – 600°C |
Available Forms
GR1 titanium is commonly available as:
| Form | Availability |
|---|---|
| GR1 titanium pipe | Yes |
| GR1 titanium tube | Yes (seamless and welded) |
| Sheets | Yes |
| Plates | Yes |
| Rods | Yes |
| Castings | Yes |
| Fittings elements | Yes |
Applications of GR1 Titanium Tube
| Industry | Application |
|---|---|
| Chemical processing | Chlorate manufacturing, desalination processes – GR1 titanium for chemical processing |
| Automotive | Performance racing exhaust systems – weight reduction |
| Industrial | Constant operations up to 425°C, intermittent up to 540°C |
GR1 titanium heat exchanger tubes are used in desalination and chemical processing. The use of GR1 titanium pipe may reduce the mass of an entire structure by 40%.
How to Weld GR1 Titanium Pipe
| Parameter | Recommendation |
|---|---|
| How to weld GR1 titanium | GTAW (TIG) with ERTi-1 filler metal |
| Argon shielding | Required on both sides |
| Preheat | Not required |
| Post-weld heat treatment | Stress relief at 450-600°C if needed |
| Note | Easily welded – good weldability |
GR1 titanium machinability is good – can be cold and hot machined. GR1 titanium forming/bending is excellent due to highest ductility among titanium grades.
FAQ
Q1: What is GR1 titanium pipe?
A: GR1 titanium pipe is unalloyed titanium with the highest purity out of all ASTM grades. Although it is the softest titanium showing the lowest strength, GR1 titanium compensates with the highest ductility at room temperature. It is the first on the list of commercially pure titanium grades.
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 Werkstoff number is 3.7025. (Note: Some sources may incorrectly show R504007 – this is a typo; R50400 is Grade 2.)
Q3: What is the maximum operating temperature for GR1 titanium pipe?
A: GR1 titanium pipe can operate continuously at temperatures up to 425°C (800°F). For intermittent working conditions, temperatures can reach up to 540°C (1000°F). GR1 titanium tube also exhibits good impact properties at low temperatures.
Q4: How much weight can be saved by using GR1 titanium pipe?
A: The use of GR1 titanium pipe may reduce the mass of an entire structure by up to 40%. Titanium grade 1 density is 4.51 g/cm³, significantly lower than steel, enabling substantial weight savings in automotive and industrial applications.
Q5: What is the yield strength of GR1 titanium pipe?
A: The minimum GR1 titanium yield strength (0.2% offset) is 138 N/mm². Tensile strength is minimum 240 N/mm². Elongation is 24%. Grade 1 titanium hardness is 115 HV.
Q6: What is the chemical composition of GR1 titanium tube?
A: GR1 titanium chemical composition limits are: Fe ≤0.20%, O ≤0.18%, N ≤0.03%, C ≤0.08%, H ≤0.015%. The low oxygen content (0.18% max) gives GR1 titanium its highest ductility among titanium grades.
Q7: What are the heat treatment requirements for GR1 titanium pipe?
A: GR1 titanium pipe can be soft annealed at 600-700°C, or stress relief heat treated at 450-600°C. Due to titanium's tendency to oxidation which causes increased brittleness, heat treatment of GR1 titanium requires a protective gas atmosphere or a vacuum.
Q8: Is GR1 titanium pipe suitable for chemical processing?
A: Yes, GR1 titanium for chemical processing is a primary application. GR1 titanium pipe is used in chlorate manufacturing and desalination processes. It is resistant to highly oxidizing and reducing environments, also when exposed to chlorides.
Q9: Is GR1 titanium pipe suitable for automotive exhaust systems?
A: Yes, GR1 titanium pipe is becoming increasingly popular in the automotive industry, especially for performance racing exhaust systems. The use of GR1 titanium tube can reduce weight by up to 40% while providing excellent corrosion resistance at high temperatures.
Inspection
| Test | Purpose |
|---|---|
| Chemical analysis | Verify GR1 titanium chemical composition (Fe, O, N, C, H limits) |
| Tensile testing | Confirm tensile strength (≥240 N/mm²), GR1 titanium yield strength (≥138 N/mm²), elongation (≥24%) |
| Hardness testing | Verify grade 1 titanium hardness (115 HV) |
| Dimensional inspection | Check OD, wall thickness, length |
| Surface inspection | Check for defects |
| Ultrasonic testing | Detect internal flaws in GR1 titanium pipe |
| Eddy current testing | Surface defect detection on GR1 titanium tube |
| Hydrostatic testing | Pressure integrity |
Packaging
GR1 titanium pipe and GR1 titanium tube packaging:
| Packaging Step | Description |
|---|---|
| 1. End protection | Plastic end caps on both ends of each GR1 titanium tube |
| 2. Inner wrapping | Plastic / VCI paper wrapped around GR1 titanium pipe |
| 3. Bundling | Steel straps securing bundles |
| 4. Wooden case | Suitable for long-distance transport by air or sea shipping |
| 5. Labeling | Grade (GR1), standard (ASTM B338/B861), dimensions, heat number |
| 6. Documentation pouch | Waterproof pouch with packing list and mill test certificate |
Factory Equipment
| Equipment | Function |
|---|---|
| VAR furnace | Vacuum Arc Remelting for high-purity titanium ingot |
| Extrusion press | Forms GR1 titanium pipe hollows from billet |
| Cold pilger mill | Reduces diameter and wall thickness |
| Annealing furnace | Soft annealing (600-700°C) and stress relief (450-600°C) – with protective gas atmosphere or vacuum to prevent oxidation |
| Pickling line | Removes oxide scale |
| Straightening machine | Corrects bending |
| Cutting machine | Precision length cutting |
| Welding equipment | For welded GR1 titanium tube (ASTM B862) |
| Ultrasonic tester | Non-destructive inspection |
| Eddy current tester | Surface defect detection |
| Hydrostatic tester | Pressure testing |
| Tensile testing machine | Mechanical property verification |
| Hardness tester | Grade 1 titanium hardness verification (115 HV) |
