Inconel 718 Round Bar
➡️ Alloy 718 | UNS N07718 | EN 2.4668
➡️ ASTM, EN, JIS & International Standards
➡️ Supply Conditions
➡️ Multiple Diameters & Supply Lengths
➡️ Global Export & International Delivery
Country of Origin:
Europe, Japan, USA
Material Type:
Nickel Alloy
UNS Number:
N07718
Wr. No.:
2.4668
MTC Available:
EN 10204 3.1
Product Description for Inconel 718 Round Bar
Inconel 718 is a precipitation-hardening nickel-chromium alloy, UNS N07718 and Werkstoff 2.4668. Stock is supplied to ASTM B637, the standard covering precipitation-hardening nickel alloy bar for high-temperature service, and to AMS 5662, AMS 5663 and AMS 5664 for aerospace work.
It is the most widely used superalloy in the world, and the reason is niobium. Where most nickel superalloys harden through gamma prime based on aluminium and titanium, 718 hardens principally through gamma double prime, a niobium-rich phase that precipitates far more slowly. That sluggishness is what makes the alloy weldable without the strain-age cracking that plagues gamma prime alloys, and weldability in a material this strong is rare.
The composition is 50-55% nickel, 17-21% chromium, 4.75-5.50% niobium plus tantalum, around 3% molybdenum, with titanium and aluminium additions and iron as the balance.
Solution treated and aged, it reaches 1275 MPa tensile minimum alongside 1034 MPa minimum proof strength, and holds useful strength to around 700 C. Above that gamma double prime converts to the stable delta phase and strength falls away.
Machining is difficult, since the material is strong, tough and work hardens aggressively, so parts are machined in the solution-treated condition before ageing wherever the geometry allows.
For rotating aerospace parts, VIM plus VAR double or triple melted material is specified along with grain size control and ultrasonic examination, because fatigue life depends on inclusion content rather than bulk chemistry.
Stock covers 6 mm to 250 mm, random length or cut to order. The alloy is essentially non-magnetic.
Typical work is gas turbine discs, blades and casings, rocket components, downhole tools, high-strength fasteners and subsea hardware.
Common Applications of Inconel 718 Round Bar
➡️ Machined shafts, spindles, valve stems, pump sleeves and pins for food, beverage, dairy and pharmaceutical equipment, where the passive chromium oxide film resists both product acids and caustic clean-in-place chemicals.
➡️ Fasteners, studs, bolts, threaded rod and anchor components produced from bar stock, chosen for corrosion resistance combined with the ductility needed for cold heading and thread rolling.
➡️ Chemical, water treatment and general process plant parts such as agitator shafts, flange blanks, nozzles and support components handling water, steam and mildly corrosive media free of significant chlorides.
➡️ Architectural and structural hardware including handrail stanchions, balustrade fittings, tension rods and bollards, where a bright ground or polished bar finish provides both appearance and low maintenance.
International Equivalent Grade for Alloy 718 Round Bar
Standard
Country / Region
Grade
ASTM B637
USA
UNS N07718 (precipitation-hardening bar)
AMS 5662
USA
UNS N07718 (solution treated and aged)
AMS 5663
USA
UNS N07718
ASTM B670
USA
UNS N07718 (plate, sheet and strip)
DIN 17744
Europe / EU
2.4668 (NiCr19Fe19NbMo3)
Technical Specification for Inconel 718 Round Bar
Specification
Value
Unit
Material
Nickel alloy
-
Grade
Inconel 718 / UNS N07718 / 2.4668
-
Product Form
Round bar / rod
-
Standard
ASTM B637, AMS 5662, AMS 5663, AMS 5664
-
Diameter
6 - 250 (typical supply range)
mm
Length
3 - 6 (random), or cut to length
m
Manufacturing Process
Hot rolled or forged, solution treated and age hardened
-
Production Route
VIM plus VAR or ESR double or triple melt for aerospace quality
-
Surface Finish
Hot-rolled and pickled, peeled, turned, centreless ground, polished
-
Heat Treatment / Delivery Condition
Solution treated 954-1010 C, double aged 718 C then 621 C
-
Tolerance Standard
ASTM B637 permissible variations
-
Density
8.19 (typical)
g/cm3
Melting Range
1260 - 1336 (typical)
C
Thermal Conductivity at 20 C
11.4 (typical)
W/m.K
Coefficient of Thermal Expansion (20-100 C)
13.0 (typical)
um/m.C
Specific Heat (0-100 C)
435 (typical)
J/kg.K
Electrical Resistivity at 20 C
1.25 (typical)
uOhm.m
Modulus of Elasticity at 20 C
200 (typical)
GPa
Magnetic Properties
Essentially non-magnetic at room temperature
-
Maximum Service Temperature
700 (typical, above which gamma double prime converts to delta phase)
C
Testing / Inspection Standard
ASTM E8 or ASTM A370 for mechanical testing, ASTM E112 for grain size
-
Certification / Inspection Documents
EN 10204 3.1 or 3.2 mill test certificate with heat treatment records
-
Technical Specifications
Get the key technical specifications for Inconel 718 Round Bar
Specify ASTM B637 under UNS N07718, or to AMS 5662, AMS 5663 or AMS 5664 for aerospace, which differ in heat treatment and property requirements. Dimensional tolerances come from the permissible variations within B637.
The standard treatment is solution at 954-1010 C followed by a double age: approximately 718 C for 8 hours, furnace cool to 621 C, and hold for a total of around 18 hours. That two-stage age is what develops the gamma double prime precipitate properly, and a single-stage age will not produce the same properties.
Solution temperature choice matters. A lower solution treatment retains delta phase at grain boundaries, which pins grain size and improves notch ductility and fatigue. A higher one dissolves it, giving better creep strength but coarser grain. Aerospace specifications are explicit about which is required, and the AMS number should be quoted rather than assumed.
The 700 C ceiling is metallurgical rather than arbitrary. Gamma double prime is metastable, and above roughly 650-700 C it converts progressively to the stable delta phase, which contributes no strengthening. Long exposure near that limit degrades properties permanently.
Machining is difficult. The material is strong, tough and work hardens aggressively, so machining in the solution-treated condition before ageing is preferred where geometry allows.
Chemical Composition for Inconel 718 Round Bar
Element
Symbol
Min
Max
Unit
Nickel
Ni
50.00
55.00
%
Chromium
Cr
17.00
21.00
%
Niobium plus Tantalum
Nb+Ta
4.75
5.50
%
Molybdenum
Mo
2.80
3.30
%
Titanium
Ti
0.65
1.15
%
Aluminium
Al
0.20
0.80
%
Cobalt
Co
-
1.00
%
Carbon
C
-
0.08
%
Manganese
Mn
-
0.35
%
Silicon
Si
-
0.35
%
Copper
Cu
-
0.30
%
Boron
B
-
0.006
%
Phosphorus
P
-
0.015
%
Sulfur
S
-
0.015
%
Iron
Fe
Balance
-
%
Chemical Composition
View the chemical composition and applicable material limits for Alloy 718 Round Bar
Niobium plus tantalum at 4.75-5.50% is the element that defines this alloy and separates it from every other nickel superalloy in common use. During ageing it forms gamma double prime, a body-centred tetragonal nickel-niobium phase that provides the bulk of the strengthening. It also precipitates slowly, which means a weld can cool through the ageing range without hardening on the way, and that is why 718 can be welded while gamma prime alloys crack.
Nickel at 50.00-55.00% forms the matrix and supplies the other half of the precipitate chemistry, along with corrosion resistance and structural stability.
Chromium at 17.00-21.00% provides oxidation and general corrosion resistance. Molybdenum at 2.80-3.30% strengthens the solid solution and adds pitting resistance, which matters for downhole and subsea use.
Titanium at 0.65-1.15% and aluminium at 0.20-0.80% form a secondary gamma prime precipitate that supplements the gamma double prime.
Iron makes up the balance, typically around 18%, and it is a deliberate cost-reducing constituent rather than an impurity.
Boron at 0.006% maximum improves stress-rupture life at grain boundaries, while carbon, phosphorus, sulphur, silicon and manganese are all held low to protect weldability and fatigue performance.
Mechanical Properties for Inconel 718 Round Bar
Mechanical Property
Value
Unit
Tensile Strength, solution treated and aged
1275
MPa (minimum)
Yield Strength 0.2% Proof, solution treated and aged
1034
MPa (minimum)
Elongation in 50 mm
12
% (minimum)
Reduction of Area
15
% (minimum)
Hardness, solution treated and aged
331
HBW (minimum)
Modulus of Elasticity
200
GPa (typical)
Mechanical Properties
Check the key mechanical properties and performance requirements of Alloy 718 Round Bar
These are ASTM B637 requirements for solution-treated and aged UNS N07718 bar. Strength, elongation and reduction of area are minima, and hardness is unusually specified as a minimum rather than a maximum, because it confirms the ageing treatment actually took place.
One point to settle at order stage: B637 bands its requirements by section size, with separate footnoted columns for bar up to 63.5 mm and from 63.5 to 101.6 mm, and further provisions for specimens taken tangentially from large disk forgings or radially from rings. The figures below apply to the smaller section band, so confirm the requirement for your actual diameter rather than reading a single headline number.
At 1275 MPa tensile minimum alongside 1034 MPa minimum proof strength, the alloy is stronger than most martensitic stainless steels while remaining tough, corrosion resistant and non-magnetic. That combination is what makes it the default choice for highly stressed components in hostile environments.
Ductility of 12% minimum elongation is modest, as expected at this strength level, and reduction of area at 15% minimum is the more sensitive indicator of whether heat treatment was carried out correctly.
Properties hold well to around 650 C and then fall away as gamma double prime converts to delta phase. For sustained service near that limit, design must use stress-rupture data rather than tensile values, and the exposure history matters because the degradation is permanent.
For rotating aerospace parts, VIM plus VAR double or triple melting is specified along with grain size control to ASTM E112 and ultrasonic examination, since fatigue life is governed by inclusions rather than by bulk chemistry.
Dimension / Sizes for Inconel 718 Round Bar
Dimension / Size
Value
Unit
Diameter
6 - 250
mm
Standard Length
3 - 6 (random / mill lengths)
m
Custom Length
Cut to length available on request
-
Diameter Tolerance
Per ASTM B637 permissible variations, varies with size and finish
-
Length Tolerance
Per ASTM B637 or as agreed at order
-
Straightness Tolerance
Per ASTM B637 or as agreed at order
-
End Condition
Square cut, chamfered, or as ordered
-
Surface Finish
Hot-rolled and pickled, peeled, turned, centreless ground, polished
-
Available Size Range
6 - 250, larger diameters by forging on enquiry
mm
Cut-to-Length Availability
Available
-
Dimensional Standard
ASTM B637
-
Dimensions & Sizes
Explore available diameters, lengths, and dimensional requirements for Alloy 718 Round Bar
Pricing for Inconel 718 Round Bar
Round Bar Prices are generally quoted per kilograms or meters tonnes and can fluctuate with the global raw material and market prices. The final price will depend on a variety of factors, including the grade size, diameter, length, surface finish, the quantity and whether the bars are cut to length or in standard lengths.
For smaller quantities, we can also quote per metre or per piece basis once the required dimensions have been confirmed. Container-loads or orders that are larger in size are typically priced per tonne, based upon the specifications required and the supply conditions.
Please provide your desired dimensions, grades, length number, and end for a current quote including the lead time applicable and details for certification.
Pricing
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Why Choose Us
Euro Steel Bars is an international distributor, stockist and exporter of stainless round steel bars that cover carbon, stainless alloy, special grades. We stock a variety of sizes and grades. We guarantee every order with mill test certificates as well as full quality-assurance documentation. Our name speaks to our roots: European-sourced materials that is backed by the certificates and rigor that buyers from Asia as well as the Gulf and Africa are looking for.
Each bar we deliver is accompanied by EN 10204 3.1 mill test certificates as well as complete documentation of quality, so what you receive corresponds to what’s written in the documents. We carry a selection of sizes and grades ready for transport, and cut length upon the request of customers, which results in quicker lead times, whether you’re ordering just a one-off spec or a complete project tonnage.
We operate an actual wholesale business that is that is supported with an internationally-operated supply chain therefore we are able to serve fabricators sourcing one grade the same way in the same way as an EPC contractor who is placing a large order. Our clients include manufacturers, fabricators EPC construction companies, engineers oil and gas projects as well as construction companies. we design our inventory as well as documentation to show what buyers need to bring projects forward.
Our customers trust us across Qatar, Oman, Bahrain, Kuwait, Jordan, Malaysia, Singapore, Thailand, Taiwan, Turkey, Italy and South Africa. If you’re looking to source an Gulf energy project, or a construction project within Southeast Asia, you get the same quality of certified material, the exact documentation, and the exact delivery procedure.
Frequently Asked Questions
What is Inconel 718 Round Bar?
Why is Inconel 718 weldable when most superalloys are not?
What heat treatment does Inconel 718 receive?
What standard does Inconel 718 Round Bar comply with?
What are the key mechanical properties of Inconel 718 Round Bar?
Why is Inconel 718 limited to around 700 C?
Is Inconel 718 suitable for sour service?
What sizes and lengths are available?
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