What Is Inconel 718 Capillary Tubing?
Inconel 718, designated UNS N07718, is a precipitation-hardening nickel-based superalloy. It achieves high strength through controlled precipitation of intermetallic phases after heat treatment. Inconel 718 capillary tubing belongs to precision tubing, distinguished from conventional pipe not merely by small outer diameter. It demands ultra-tight dimensional tolerances, uniform wall thickness and defect-free inner surface. This tubing is widely deployed in aerospace instrumentation, requiring full PMI inspection and consistent metallurgical properties for critical fluid and signal transmission systems.
We manufacture both seamless Inconel 718 capillary tubes and welded Inconel 718 capillary tubes to meet different engineering requirements. During the surface finishing process, we offer MP, EP, BA, AP and other polishing options to achieve the level of cleanliness and smoothness required by your application.
What are the key features & requirements for Inconel 718 capillary tube?
Inconel 718 (UNS N07718) is a precipitation-hardening nickel superalloy, retaining high tensile strength and fatigue resistance across cryogenic and moderate high-temperature ranges. Its capillary tube maintains strict precision tube dimensions with small outer diameters and ultra-thin wall thickness. Aerospace buyers shall verify the delivery condition, typically solution treated and aged, and check OD, wall tolerances. PMI verification, pressure testing and full material traceability are mandatory to confirm compliance for aerospace tubing applications.
Inconel 718 Capillary Tube (UNS N07718) Drawing & Formula
Formula: m = (OD – THK) × THK (mm) × L (m) × ρ (g/cm³) × π ÷ 1000
OD = Outside Diameter, THK = Wall Thickness, L = Length
ρ = Density, π = 3.1415926
Example Calculation & Comparison
We provide two typical Inconel 718 capillary tube examples for your weight estimation.
- Regular precision capillary: OD 3.0 mm, THK 0.2 mm, 1m length, weight ≈0.0145 kg
- Ultra-fine capillary: OD 1.5 mm, THK 0.1 mm, 1m length, weight ≈0.0036 kg
This formula supports fast weight calculation of UNS N07718 tubing, helpful for quotation, material planning and cost comparison for aerospace instrument projects.
Inconel 718 Capillary Tube (UNS N07718) Chemical Composition
| Grade | Standard | C | Si | Mn | P | S | Cr | Ni | Ti |
| 718 | ASTM | ≤0.08 | ≤0.35 | ≤0.35 | ≤0.015 | ≤0.015 | 17.00-21.00 | 50.0-55.0 | 0.65-1.15 |
Inconel 718 Capillary Tube (UNS N07718) Mechanical Properties
| Element | Yield Strength (0.2%Offset) | Melting Point | Density | Tensile Strength | Elongation |
| 718 | MPa – 1034 | 1336 °C (2437 °F) | 8.19 g/cm3 | MPa – 1241 | Min 10 % |
Which Standards Apply to Inconel 718 Tubes?
ASTM B983 covers seamless high-strength nickel alloy tubing including UNS N07718, yet listing under this standard does not automatically qualify all capillary sizes or aerospace-grade usage. Buyers must verify the standard revision, product form, dimensional range, delivery heat treatment state and mandatory inspection items before ordering. The checking workflow confirms chemical composition, mechanical test, PMI and non-destructive examination records. For aerospace instrumentation capillary tubing, additional AMS specifications may be required to meet stricter industrial requirements.
Inconel 718 Capillary Tube Applicable Standards Table
| Standard | Material Grade | Product Form | Scope Note | Key Inspection Requirements |
|---|---|---|---|---|
| ASTM B983 | UNS N07718 | Seamless nickel alloy tubing | Covers seamless Inconel 718 tube; capillary ultra-small OD / thin wall needs case-by-case confirmation | Chemical analysis, tensile test, hardness, NDT, dimensional check |
| AMS 5589 | UNS N07718 | Aerospace seamless tubing | For aerospace service, tighter tolerance than ASTM B983 | Heat treatment validation, PMI, ultrasonic / eddy current testing |
| AMS 5590 | UNS N07718 | Aerospace seamless tubing | Precipitation hardened condition for high strength aerospace components | Full mechanical property test, grain size control, corrosion check |
Applicable standards for Inconel 718 capillary tube. Please confirm the revision and dimension eligibility before technical approval.
Contact us for the latest export price quote for Inconel 718
Inconel 718 Capillary Tube Dimensions - Micro Tubing
Nominal dimensions for quotation and manufacturing capability confirmation. Units: mm.
|
Outside Diameter (OD) |
Wall Thickness (WT) |
Calculated Inside Diameter (ID) |
Specification Status |
|---|---|---|---|
|
0.50 |
0.10 |
0.30 |
Custom manufacturing subject to confirmation |
|
0.80 |
0.10 |
0.60 |
Custom manufacturing subject to confirmation |
|
1.00 |
0.10 |
0.80 |
Custom manufacturing subject to confirmation |
|
1.00 |
0.15 |
0.70 |
Custom manufacturing subject to confirmation |
|
1.50 |
0.15 |
1.20 |
Custom manufacturing subject to confirmation |
|
1.50 |
0.20 |
1.10 |
Custom manufacturing subject to confirmation |
|
2.00 |
0.15 |
1.70 |
Custom manufacturing subject to confirmation |
|
2.00 |
0.20 |
1.60 |
Custom manufacturing subject to confirmation |
|
2.00 |
0.25 |
1.50 |
Custom manufacturing subject to confirmation |
|
2.50 |
0.20 |
2.10 |
Custom manufacturing subject to confirmation |
|
3.00 |
0.25 |
2.50 |
Custom manufacturing subject to confirmation |
|
3.00 |
0.30 |
2.40 |
Custom manufacturing subject to confirmation |
Inconel 718 Precision Tube Dimensions - OD 3.18 mm and Above
Nominal dimensions for preliminary specification review. Units: mm.
|
Outside Diameter (OD) |
Wall Thickness (WT) |
Calculated Inside Diameter (ID) |
AMS 5589H Dimensional Scope Screening |
|---|---|---|---|
|
3.18 |
0.38 |
2.42 |
Meets the published minimum OD and WT thresholds |
|
3.18 |
0.50 |
2.18 |
Meets the published minimum OD and WT thresholds |
|
4.00 |
0.38 |
3.24 |
Meets the published minimum OD and WT thresholds |
|
4.00 |
0.50 |
3.00 |
Meets the published minimum OD and WT thresholds |
|
4.76 |
0.50 |
3.76 |
Meets the published minimum OD and WT thresholds |
|
6.00 |
0.50 |
5.00 |
Meets the published minimum OD and WT thresholds |
|
6.35 |
0.50 |
5.35 |
Meets the published minimum OD and WT thresholds |
|
6.35 |
0.89 |
4.57 |
Meets the published minimum OD and WT thresholds |
|
8.00 |
0.50 |
7.00 |
Meets the published minimum OD and WT thresholds |
|
10.00 |
1.00 |
8.00 |
Meets the published minimum OD and WT thresholds |
Important: Meeting the minimum dimensional thresholds does not establish full compliance with AMS 5589H. Material condition, manufacturing requirements, testing, and other applicable provisions must also be satisfied.
Aerospace Applications of Inconel 718 Capillary Tube
- Rocket engine propellant transfer lines for liquid hydrogen and liquid oxygen. The capillary maintains stable flow under cryogenic conditions and bears cyclic pressure loads during engine operation.
- Thrust chamber cooling channels. The precision capillary structure delivers cooling medium evenly to dissipate extreme heat and protect the thrust chamber from thermal damage.
- Engine gas supply ducts. This thin-wall capillary transmits high-temperature gas, relying on Inconel 718's high-temperature strength to resist thermal fatigue and creep deformation.
- Combustion chamber shell micro fluid passages. The tight-tolerance capillary supports fluid monitoring and pressure control under alternating high temperature and pressure environments.
Get Aerospace-Grade Inconel 718 Capillary Tube Quote
These critical aerospace components require ultra-precise dimensional tolerance, stable heat treatment status and 100% non-destructive testing. Submit your technical drawings and parameter demands to get verified aerospace-grade Inconel 718 capillary tube solutions.
Why Choose Gnee as Your Nickel-Based Alloy Supplier?
We implement strict batch inspection, full material traceability and complete export packaging to avoid material mix-up, dimensional deviation and surface defects for your high-temperature and corrosion-resistant projects.
1.Dimensional inspection. We use laser micrometers and high-precision wall thickness gauges to measure OD, wall thickness and length tube by tube. All readings stay within tight precision tolerances to guarantee consistent assembly for aerospace instrumentation.
2.PMI composition inspection. A handheld optical emission spectrometer scans every batch to verify Ni, Cr, Nb and Fe content. The test confirms compliance with ASTM B983 / AMS specifications and eliminates material mix-up risks.
3.Surface visual inspection. Operators inspect inner and outer tube surfaces for scratches, oxide residues and micro-defects to meet aerospace-grade surface requirements. All test records are logged and double-checked before shipment for full material traceability.
4.Packaging & shipping. Capillary tubes are protected with anti-scratch plastic sleeves, fixed in custom foam trays, then packed into sturdy export cartons with securing straps and handling marks to prevent bending and surface damage during transit.
