Inconel 718 (UNS N07718): Round Bars, Seamless Tubes & Plates — Technical Data Sheet

Quick Answer: What Is Inconel 718?

Inconel 718 (UNS N07718 / W.Nr. 2.4668 / GH4169) is a premier precipitation-hardening nickel-iron-chromium superalloy formulated for service environments demanding high mechanical strength and exceptional corrosion resistance. Its high performance stems from the precipitation hardening through gamma-prime (γ′) and gamma-double-prime (γ″) phases nucleated by aluminum (0.2–0.8%), titanium (0.65–1.15%), and niobium (4.75–5.50%) within its stable nickel-chromium matrix. This requires a carefully controlled solution anneal followed by a two-stage aging cycle to achieve full hardening. Operating efficiently from cryogenic limits down to -253°C up to a useful strength limit of approximately 700°C (1300°F), Inconel 718 is widely utilized in aerospace turbine discs, rocket engines, high-strength fasteners, and oil & gas downhole tools.

Product Overview

At the atomic level, its face-centered cubic (FCC) austenitic matrix that retains exceptional toughness even at cryogenic temperatures. Its primary advantage is precipitation hardening, which produces a yield strength nearly double that of solid-solution alloys while maintaining good fatigue resistance, which yields good oxidation and corrosion resistance combined with outstanding high-cycle fatigue strength and creep-rupture performance.

Shanghai Hangbo Alloy Group Co., Ltd., established in 2012, stands as a top-tier global manufacturer and supplier of Inconel 718. Operating under a certified ISO 9001:2015 quality management system, we command an export network covering 50+ countries. Our portfolio contains high-precision centerless ground round bars, heavy industrial plates, and high-pressure seamless tubing engineered for critical industrial applications. By managing carbon distribution and grain refinement during melting and forging, we ensure our material provides robust structural performance under severe stress. Every order comes with 100% material traceability and certified documentation, ensuring compliance with strict global engineering standards.

Executive Standards

Shanghai Hangbo Alloy Group Co., Ltd. manufactures Inconel 718 in strict compliance with international technical specifications:

Note: Shanghai Hangbo executes 100% confirmation of chemical compliance using Optical Emission Spectroscopy (OES) for every melt lot.

Chemical Composition

The corrosion-resistant profile of Inconel 718 depends on its exact chemical balance. Chromium ensures high-temperature oxidation resistance, while molybdenum safeguards against localized pitting in chloride environments.

Mechanical Properties

Inconel 718 delivers excellent design allowable stresses. The data below outlines typical properties for annealed stock.

Room-Temperature Mechanical Properties

High-Temperature Performance: Strength Retention Analysis

Inconel 718 retains remarkable mechanical properties under thermal stress, establishing its credentials as a critical superalloy:

How Inconel 718 Is Produced

Round Bar & Forging

• 1. Triple Melting (VIM + VAR/ESR): Vacuum Induction Melting followed by Vacuum Arc Remelting or ESR ensures ultra-high purity and ingot soundness.
• 2. Hot Forging: large ingots are isothermally forged on hydraulic presses to refine grains and achieve directional integrity.
• 3. Solution Treating & Aging: a precisely controlled two-stage age cycle develops the γ′/γ″ precipitate distribution for peak strength.
• 4. Precision Grinding: bars are centerless-ground to h8/h9 tolerances with Ra under 0.8 μm.

Seamless Tube & Pipe

• 1. Billet Piercing & Extrusion: forged rounds are pierced and extruded into heavy-walled hollows.
• 2. Cold Drawing / Pilgering: multi-pass reductions produce uniform wall thickness and tight concentricity.
• 3. Solution + Age Heat Treatment: tubes are heat-treated to develop full precipitation-hardened properties.
• 4. Defect Testing: 100% Eddy Current and hydrostatic testing per ASTM standards.

Sheet, Plate & Strip

• 1. Hot Rolling: slabs are hot-rolled with controlled reduction to avoid segregation.
• 2. Cold Rolling: precise gauge control to within ±0.05 mm.
• 3. Solution + Age: plate is heat-treated to achieve specified aged strength.
• 4. Pickling & Leveling: scale removal and tension leveling for flatness.

Industry Applications: Solving Engineering Challenges

Aerospace and Defense

Inconel 718 is the workhorse alloy for jet engine turbine discs, compressor blades, and rocket engine turbopump components. Its high strength-to-weight ratio and fatigue resistance are critical for flight safety.

Oil & Gas

Used for high-strength downhole tools, wellhead components, and fasteners that must resist both high stress and sour-gas (H2S) environments.

Cryogenic Engineering

Its FCC structure retains exceptional toughness at liquid-nitrogen and liquid-hydrogen temperatures, making it suitable for rocket fuel systems.

Power Generation

718 is widely used for gas-turbine discs, seals, and high-temperature fasteners in land-based power plants.

Quality Assurance: 7-Stage Zero-Defect Inspection Protocol

Shanghai Hangbo Alloy Group Co., Ltd. deploys an intensive inspection matrix to support a zero-defect mandate across all production lines:

• 1. Chemical verification: OES analysis on every melt batch alongside handheld PMI validation on finished products ensures composition parameters match executive limits.
• 2. Ultrasonic Testing (UT): Performed per ASTM A388 standards across all bars and plates to confirm the absence of inner voids, seams, or gas inclusions.
• 3. Eddy Current Testing (ET): Applied 100% to tubes following ASTM E309 protocols to check surface and sub-surface continuity.
• 4. Hydrostatic Pressure Verification: Tubes undergo hydrostatic tests up to 10,000 PSI to verify wall integrity under high-pressure parameters.
• 5. Mechanical Destructive Testing: Tensile, offset yield, elongation, and Brinell hardness examinations are executed per heat lot to verify strength criteria.
• 6. Dimensional Metrology Check: Digital calipers and computerized laser sensors measure geometry, guaranteeing all diameter, wall, and length tolerances match orders.
• 7. Visual and Microstructure Audit: Surface quality checks are paired with metallographic microscope tests to evaluate grain size (ASTM E112) and phase homogeneity.

All items leave our facilities accompanied by ISO 9001:2015 certification and EN 10204 3.1 Mill Test Certificates. Third-party inspection options through SGS, TUV, or Bureau Veritas (BV) are organized upon customer request.

Frequently asked questions