GH4169 (Inconel 718) Cold-drawn Tube Process Guide
GH4169 (Inconel 718) Cold-drawn Tube Process Guide
The production of GH4169 (Inconel 718) cold-drawn tubing involves multiple cold drawing passes, intermediate annealing (950-1050℃), and high-strength precipitation hardening (aging treatment) to achieve high strength (>1000 MPa) and tight tolerances. Due to its work-hardening properties, frequent annealing is required to restore ductility, and precise lubrication is necessary.
Is Inconel 718 difficult to machine?
This nickel-based superalloy is a common material in the aerospace industry, possessing excellent strength and heat resistance-but these very properties make it extremely difficult to machine. Inconel 718 is prone to rapid work hardening, generating extremely high temperatures at the tool-workpiece interface, thus accelerating tool wear.
1. GH4169 Cold-drawn Tube Product Overview and Scope
| Parameter | Description |
|---|---|
| Material | GH4169 (UNS N07718 / Inconel 718) |
| Product Form | Cold Drawn Seamless Tube |
| Manufacturing Process | Cold drawing (multiple passes + intermediate annealing) |
| Surface Condition | As-drawn (bright) / Annealed & Pickled (AP) / Bright Annealed (BA) |
| Applicable Standards | AMS 5589, AMS 5590, ASTM B983, GB/T 14994 |
| Typical Applications | Aerospace hydraulic lines, fuel systems, high-pressure instrumentation, nuclear industry precision tubing |
| Maximum Service Temperature | 650 – 700°C (load-bearing) |
2. Chemical composition of GH4169 cold-drawn tube (weight %)
| Element | Content (%) | Function |
|---|---|---|
| Nickel (Ni) | 50.0 – 55.0 | Matrix element; high-temperature stability |
| Chromium (Cr) | 17.0 – 21.0 | Oxidation and corrosion resistance |
| Iron (Fe) | Balance (~18-20) | Fe-Ni-Cr base alloy |
| Niobium (Nb) | 4.75 – 5.50 | Core strengthening element – forms γ″ phase (Ni₃Nb) |
| Molybdenum (Mo) | 2.80 – 3.30 | Solid-solution strengthening; creep and pitting resistance |
| Titanium (Ti) | 0.65 – 1.15 | Forms γ′ strengthening phase |
| Aluminum (Al) | 0.20 – 0.80 | Forms γ′ strengthening phase; improves oxidation resistance |
| Carbon (C) | ≤ 0.08 | Low carbon for weldability and toughness |
| Manganese (Mn) | ≤ 0.35 | Deoxidizer |
| Silicon (Si) | ≤ 0.35 | Deoxidizer |
| Phosphorus (P) | ≤ 0.015 | Ensures toughness |
| Sulfur (S) | ≤ 0.015 | Ensures hot workability |
| Boron (B) | 0.002 – 0.006 | Grain boundary strengthener; improves stress rupture life |
| Cobalt (Co) | ≤ 1.00 | Residual element |
| Copper (Cu) | ≤ 0.30 | Residual element |
3. High-temperature mechanical properties of GH4169 cold-drawn tube (aging state)
| Temp (°C) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Strength Retention |
|---|---|---|---|---|
| 20 (RT) | ≥ 1275 | ≥ 1035 | ≥ 12 | 100% |
| 300 | ~1200 | ~1000 | ~15 | 94% |
| 400 | ~1180 | ~980 | ~15 | 92% |
| 500 | ~1150 | ~950 | ~16 | 90% |
| 600 | ~1100 | ~900 | ~18 | 86% |
| 650 | ~1000 | ~850 | ~20 | 78% |
| 700 | ~850 | ~750 | ~22 | 66% |
| 760 | ~600 | ~550 | ~25 | 47% |
Click to download the GH4169 alloy PDF file now
4. GH4169 Cold Drawing Process Parameters
| Parameter | Description |
|---|---|
| Starting Material | Hot extruded or hot pierced hollow |
| Drawing Passes | Multiple passes |
| Reduction per Pass | 20% – 40% |
| Intermediate Annealing | After every 1-3 passes (954-982°C) |
| Lubrication | Specialized cold drawing lubricants |
| Final Heat Treatment | Solution treated or solution treated + aged (as required) |
| Finish Options | As-drawn, ground, polished, BA, AP |
Our GH4169 cold-drawn tube process flow
Phase 1: Vacuum Induction Melting + Vacuum Arc Remelting (VAR) Dual Vacuum Melting
The quality of our precision tubing originates from the furnace. We employ both Vacuum Induction Melting (VIM) and Vacuum Arc Remelting (VAR) processes to ensure an ultra-clean microstructure. This eliminates non-metallic inclusions, which are the initiation points for fatigue cracks.
Phase 2: Precision Multi-Pass Drawing and Stress Relief
We use a specialized floating mandrel and limit the cross-sectional thinning (15-22% per draw). This controlled process manages the strain hardening of the nickel-chromium matrix, preventing the "orange peel" effect and ensuring a smooth tubing surface.
Phase 3: Vacuum Bright Annealing (BA)
To address the "internal scale" problem, each tube undergoes bright annealing in pure hydrogen or a high vacuum environment. This ensures a mirror-like inner diameter (ID), crucial for transporting high-purity fluids in aerospace fuel lines.
8. Non-destructive testing (NDT) requirements for GH4169 cold-drawn tubes
| Test Method | Requirement | Standard | Acceptance Criteria |
|---|---|---|---|
| Eddy Current Testing (ET) | 100% | ASTM E426 | No relevant indications |
| Ultrasonic Testing (UT) | As specified (wall ≥ 0.5mm) | ASTM E213 | No defects exceeding 5% wall |
| Hydrostatic Test | 100% | ASME Section VIII | 1.5× working pressure, no leakage |
| Helium Leak Test | As specified | ASTM E498 | ≤ 1 × 10⁻⁹ std cc/sec |
| Visual Inspection | 100% (10-30x magnification) | ASTM E543 | No surface defects |
| Borescope Inspection | 100% (small diameters) | – | Smooth, clean ID |
Why source GH4169 cold-drawn tubing from Tier 1 manufacturer Gnee Alloy?
✅️Direct Factory Price: Eliminate middleman markups and secure the best wholesale rates for High-Performance Tubing.
✅️MTC 3.1 Traceability: Full heat-analysis and mechanical property test reports (elevated temp tensile) included with every order.
✅️Wholesale Inventory: Massive stock of standard Sch 40, Sch 80, and Capillary sizes for Fast Global Shipping.
✅️AS9100 Certified: Manufactured under the world's most rigorous aerospace quality management protocols.
Gnee Alloy GH4169(inconel 718) Certificate
📦 Packaging and Shipping
All Nickel Based Alloy products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Steel GH4169 Product Packing
Contact us for the latest export price quote for GH4169 Alloy
FAQ
Q1: Can your GH4169 cold-drawn tubes replace Inconel 718 in my blueprint?
A: Yes. GH4169 is the technische designation used in international blueprints for UNS N07718. They are chemically and mechanically identical, conforming to AMS 5589 and AMS 5590.
Q2: How do you guarantee zero-leaks in high-pressure reactors?
A: We perform 100% Hydrostatic Pressure Testing and Eddy Current (ET) testing. Our superior Concentricity Control (≤5%) ensures that the tube wall can handle its rated burst pressure without localized failure.
Q3: Can you produce non-standard thin-wall capillary tubes?
A: Absolutely. We specialize in Custom Fabrication for ultra-fine sizes, providing ODs from 0.5mm with wall thicknesses as thin as 0.05mm, all with a mirror BA finish.
Q4: Do you support small batch R&D orders?
A: Yes. As a Reliable Supplier, we support innovation. We offer Flexible MOQs on standard diameters for prototype development and material validation.
