Inconel 751 pipes and tubes (UNS N07751) are made to order from Alloy 751, an age hardenable nickel alloy developed for high temperature exhaust valve applications. The alloy is a modified version of Inconel X 750 with a higher aluminium content, giving it improved strength in the 815°C to 870°C range. Its original development was aimed at internal combustion engine exhaust valves, where the material must withstand sustained heat and repeated thermal loading. Amardeep Steel supplies Inconel 751 pipes and tubes on a made to order basis. Compare our Inconel X-750 pipes and tubes, see Inconel 718 pipes and tubes, or browse all Inconel pipes and tubes. Every order comes with mill test certificates to EN 10204 3.1 and full heat traceability.
What Are Inconel 751 Pipes and Tubes?
Inconel 751 is a nickel-chromium alloy capable of being hardened through precipitation, and it is reinforced with the presence of titanium, aluminum, and niobium as well. In contrast to X-750, it has a higher aluminum content (ranging between 0.9% and 1.5%), which increases its rupturing durability at temperatures between 815 °C and 870 °C, as well as makes it resistant to oxides produced during combustion of the fuel.
How Alloy 751 Tube Is Made
Alloy 751 is produced as round bar. Tube and hollow sections are made by boring or gun drilling bar to the required ID, then heat treated. This suits short to medium lengths for valve, nozzle and hot section parts. Send us the finished dimensions and we will confirm the route.
Inconel 751 Pipe and Tube Specifications
Parameter | Details |
|---|---|
Grade | UNS N07751, Inconel 751, Alloy 751 |
Material | Alloy 751 bar to the producer specification or your drawing |
Tube form | Bored or gun drilled tube and hollow bar, made to order |
Condition | Solution treated, or solution treated and aged |
Length | Random, fixed and cut lengths |
Ends | Plain end; bevelled on request |
Test Certificate | EN 10204 3.1, with 3.2 available on request |
Inconel 751 Chemical Composition
Element | Content (%) |
|---|---|
Nickel + Cobalt (Ni + Co) | 70.0 min |
Chromium (Cr) | 14.0 to 17.0 |
Iron (Fe) | 5.0 to 9.0 |
Titanium (Ti) | 2.0 to 2.6 |
Aluminium (Al) | 0.9 to 1.5 |
Niobium + Tantalum (Nb + Ta) | 0.7 to 1.2 |
Manganese (Mn) | 1.0 max |
Silicon (Si) | 0.5 max |
Copper (Cu) | 0.5 max |
Carbon (C) | 0.10 max |
Sulfur (S) | 0.01 max |
Main element limits from the Special Metals bulletin. Confirm minor element limits against the purchase specification.
Inconel 751 Mechanical Properties
Property (typical, aged) | Value |
|---|---|
Tensile Strength | 1310 MPa (190 ksi) |
Yield Strength (0.2% offset) | 976 MPa (141.5 ksi) |
Elongation | 22.5% |
Hardness | 352 HB |
Typical room temperature values for bar direct aged 2 hours at 732°C, as reported by the producer. These are not specification minimums.
Inconel 751 Physical Properties
Property | Typical value |
|---|---|
Density | 8.22 g/cm³ |
Melting range | 1390°C to 1430°C |
Mean thermal expansion (21°C to 93°C) | 12.6 µm/m·°C |
Modulus of elasticity | 214 GPa |
Typical values from the alloy producer. Values for each heat are on the mill certificate.
Inconel 751 Equivalent Grades
Standard | Designation |
|---|---|
UNS | N07751 |
Trade names | Inconel 751, Alloy 751 |
Closest grade | Inconel X-750 (N07750), lower aluminium |
EN / W.Nr | No widely used EN number; order by UNS N07751 |
Inconel 751 vs X-750 vs 718
Property | Inconel 751 | Inconel X-750 | Inconel 718 |
|---|---|---|---|
Aluminium | 0.9 to 1.5% | 0.40 to 1.00% | 0.2 to 0.8% |
Titanium | 2.0 to 2.6% | 2.25 to 2.75% | 0.65 to 1.15% |
Niobium | 0.7 to 1.2% | 0.70 to 1.20% | 4.75 to 5.5% |
Strength focus | 815°C to 870°C | Up to about 700°C | Up to about 650°C |
Common form | Bar (valves) | Bar, sheet, tube | All forms |
For standard seamless tubing, see our Inconel X-750 pipes and tubes (AMS 5582).
Inconel 751 Tube Size and Weight Chart
OD (mm) | 1.5 mm wall | 2.0 mm wall | 3.0 mm wall | 4.0 mm wall | 6.0 mm wall |
|---|---|---|---|---|---|
12.70 | 0.43 | 0.55 | 0.75 | n/a | n/a |
19.05 | 0.68 | 0.88 | 1.24 | n/a | n/a |
25.40 | 0.93 | 1.21 | 1.74 | 2.21 | 3.01 |
31.75 | 1.17 | 1.54 | 2.23 | 2.87 | 3.99 |
38.10 | 1.42 | 1.86 | 2.72 | 3.52 | 4.97 |
50.80 | 1.91 | 2.52 | 3.70 | 4.83 | 6.94 |
63.50 | 2.40 | 3.18 | 4.69 | 6.15 | 8.91 |
76.20 | 2.89 | 3.83 | 5.67 | 7.46 | 10.88 |
Indicative weights in kg/m for made to order tube, calculated at 8.22 g/cm³ as (OD minus wall) x wall x π x 8.22 / 1000. This alloy has no standard pipe schedule; any OD and wall within the mill or machining range can be quoted.
Applications of Inconel 751 Pipes and Tubes
- Internal combustion engine exhaust valve parts
- Hot section sleeves and nozzles
- Turbocharger and exhaust components
- High temperature fixtures and tooling
Testing and Documentation
Every order of Inconel 751 pipe and tube goes through the checks below at our testing facility or approved third party labs.
- Chemical analysis and PMI
- Tension test after the specified heat treatment
- Hardness test
- Ultrasonic test for wall soundness
- Heat treatment record supplied with the certificate
- Visual and dimensional inspection
Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.
Packing and Marking
Each length is marked with UNS N07751, size, heat number and manufacturer name. Ends are capped and tubes are packed in wooden boxes, kept apart from carbon steel. Read more about our packing and despatch process.
Request a Quote for Inconel 751 Pipes & Tubes
Send us the drawing or finished OD, ID, length, heat treatment and quantity, and our team will reply with price and delivery. Use the enquiry form or reach us through the contact page.
Frequently Asked Questions
What is Inconel 751?
Inconel 751 (UNS N07751) is a precipitation hardenable nickel-chromium alloy, a higher aluminium version of X-750, developed for engine exhaust valves.
Is Inconel 751 available as pipe?
Alloy 751 is produced as round bar. Tube and hollow sections are made to order by boring or gun drilling.
What is the difference between Inconel 751 and X-750?
Inconel 751 has more aluminium (0.9% to 1.5% against 0.40% to 1.00%), which gives higher strength at 815°C to 870°C.
What is the density of Inconel 751?
The density of Inconel 751 is 8.22 g/cm³.
