Inconel 718 Round Bar Supplier — ASTM B637 / UNS N07718 (Ex-Stock India)

High-strength, corrosion-resistant nickel superalloy round bars — ex-stock in Mumbai, exported worldwide.

ASTM B637 / ASME SB637 | UNS N07718 | Werkstoff 2.4668 | Sizes 3 mm to 600 mm

Standard ASTM B637 / ASME SB637 Certified
Size Range 3 mm to 600 mm Round Bar Diameter
Forms Round Bar, Hex Bar, Square Bar, Flat Bar
Certification ISO 9001:2015 and EN 10204 3.1 / 3.2 MTC
Material UNS N07718 / WNR 2.4668 Nickel Superalloy
Export Global Export to 25+ Countries
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Unifit Fastener is a trusted supplier and manufacturer of Inconel 718 round bar to the aerospace, oil and gas, power generation and chemical processing industry in India and globally. In addition, we offer the full range of associated parts such as Inconel 718 fasteners and Inconel 718 tube plugs to ASME SB637 and ASTM B637, in UNS N07718 and Werkstoff 2.4668. Not only do our Inconel 718 round bars offer a superior tensile strength but they also boast outstanding creep-rupture resistance and reliability at temperatures up to 700°C, while other nickel-chromium superalloy grades, like Inconel 625 round bar and Incoloy 825 round bar, offer higher-temperature or corrosion resistance properties. Each batch supplied is accompanied by a full mill test certificate, third party inspection report and a 100% traceability of the chemical and mechanical testing report. From a small trial order to a bulk shipment, Unifit Fastener is the sure bet for engineers, EPC contractors and procurement teams who have no tolerance for compromises on quality, documentation or timeliness.

Explore our full round bars range or contact our sales team for a tailored quote.

What is Inconel 718 Round Bar?

Inconel 718 (UNS N07718, Werkstoff 2.4668) is a precipitation-hardenable nickel-chromium alloy strengthened with niobium and molybdenum in a nickel-iron-chromium matrix. Unlike standard nickel alloy round bar grades, Inconel 718 retains its strength during welding and can be aged after fabrication without cracking, which is why it dominates aerospace, gas turbine, and high-pressure oilfield applications. The round bar form is produced through vacuum induction melting, forging, and hot/cold rolling, followed by solution annealing and precipitation hardening to achieve its signature combination of strength and ductility. For lower-temperature or general corrosion-resistant needs, customers can also compare our stainless steel round bar and duplex steel round bar ranges.

Technical Data

Specification

Parameter Details

Standard

ASTM B637 / ASME SB637

UNS Designation

N07718

Werkstoff Number (WNR)

2.4668

Other Standards

AMS 5662, AMS 5663, AMS 5664, NACE MR-01-75

Form

Round Bar, Hex Bar, Square Bar, Flat Bar

Diameter Range

3 mm – 600 mm

Length

0.5 m – 6 m (cut length available)

Supply Condition

Precipitation Hardened (PH), Hardened & Tempered (H&T), Annealed (ANN)

Manufacturing Method

Forged / Rolled

Surface Finish

Black, Peeled, Polished, Bright, Rough Turned

Origin Available

Indian, European, Japanese

Certification

MTC EN 10204 3.1 / 3.2, Third-Party Inspection

Chemical Composition (Inconel 718 / UNS N07718)

Element Symbol Min % Max %

Nickel

Ni

50.00

55.00

Chromium

Cr

17.00

21.00

Iron

Fe

Balance

Balance

Niobium (Columbium)

Nb (Cb)

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

Phosphorus

P

-

0.015

Sulphur

S

-

0.015

Copper

Cu

-

0.30

Boron

B

-

0.006

Mechanical Properties (Room Temperature)

Property Value

Tensile Strength

1,035 – 1,375 MPa (150 – 200 ksi)

Yield Strength (0.2% Offset)

min 827 – 1,034 MPa

Elongation

min 12% (up to 45% typical)

Hardness

typically HRC 36 – 44

Density

8.19 – 8.22 g/cm³

Melting Point

1,260°C – 1,336°C (2,300°F – 2,437°F)

Inconel 718 Round Bar Size Chart

ASTM / Canadian Bar Size Diameter (mm²) Metric Diameter (mm) US Bar Size Diameter (inch)

10M

100

5

#2

0.250

15M

200

5.5

#3

0.375

20M

300

6

#4

0.500

25M

500

7

#5

0.625

30M

700

8

#6

0.750

35M

1000

9

#7

0.875

45M

1500

10

#8

1.000

55M

2500

11

#9

1.125

-

-

12

#10

1.250

-

-

14

#11

1.375

-

-

16

#12

1.500

Comparison Table: Inconel 718 vs Inconel 625 vs Incoloy 825

Property Inconel 718 Inconel 625 Incoloy 825

UNS

N07718

N06625

N08825

Strengthening Mechanism

Precipitation (age) hardening

Solid solution strengthened

Solid solution strengthened

Max Service Temp.

~700°C

~980°C

~550°C

Tensile Strength

1,035–1,375 MPa

827–1,100 MPa

586–800 MPa

Best Suited For

High strength + moderate heat (turbine discs, fasteners)

Extreme heat + corrosion (exhaust, chemical processing)

Sulphuric/phosphoric acid environments

Weldability

Good (slow-aging)

Excellent

Good

See also our detailed comparison guide: ‘Duplex vs Super Duplex Steel Fasteners’ and ‘Advantages of Nickel Alloy Fasteners’ for more grade-selection guidance. You may also browse Hastelloy round bar and Monel round bar as alternative high-performance options.

Applications / Industries

  • Aerospace — jet engine components, turbine discs, rings, casings, Inconel bolts
  • Oil & Gas — wellhead components, subsea fasteners, Inconel stud bolts, tubing hangers
  • Power Generation — gas turbine parts, liquid fuel rocket motor components
  • Chemical Processing — pumps, valves, reactor internals
  • Cryogenic Storage Tanks and pressure vessels
  • Nuclear Reactor internal components
  • Marine & Defence — high-strength fasteners, Inconel washers, and shafting

Read more: our blog covers detailed use cases in ‘Applications and Uses of Inconel Fasteners’ and ‘Why Inconel 718 Bolts Are Preferred for High-Temperature Environments’.

Manufacturing Process & Quality Control

Manufacturing Process

  • Raw material melting (VIM/VAR) → Ingot casting → Forging/Hot rolling
  • Solution annealing → Precipitation (age) hardening heat treatment
  • Straightening, centreless grinding, peeling, or polishing to finish
  • Cutting to length, marking, and packing for dispatch

Quality Control & Testing

  • Chemical analysis / spectro analysis
  • Mechanical testing — tensile, yield, elongation, reduction of area
  • Hardness testing (Rockwell HRC / Brinell HB / Vickers HV)
  • Positive Material Identification (PMI)
  • Ultrasonic and dye-penetrant testing
  • Micro/macro structure examination

Certifications & Standards

  • ASTM B637 / ASME SB637
  • AMS 5662 / AMS 5663 / AMS 5664 / AMS 5832 / AMS 5914 / AMS 5962
  • NACE MR-01-75 / ISO 15156
  • ISO 9001:2015 Quality Management System
  • EN 10204 3.1 & 3.2 Mill Test Certificates
  • PED 2014/68/EU compliance where applicable

Frequently Asked Questions 

What is Inconel 718 round bar?

Inconel 718 round bar is a precipitation-hardenable nickel-chromium superalloy bar (UNS N07718, Werkstoff 2.4668) known for its high strength, excellent creep-rupture resistance, and stability at temperatures up to 700°C. It is produced under ASTM B637 / ASME SB637 specifications.

What is the standard size range of Inconel 718 round bar?

Unifit Fastener stocks Inconel 718 round bar from 3 mm to 600 mm in diameter and 0.5 m to 6 m in length, available in round, hex, square, and flat bar forms, with custom cut lengths on request.

What is the chemical composition of Inconel 718?

Inconel 718 primarily contains 50–55% nickel, 17–21% chromium, balance iron, 4.75–5.5% niobium, 2.8–3.3% molybdenum, and controlled amounts of titanium, aluminium, and carbon, giving it its precipitation-hardening capability.

What industries use Inconel 718 round bar?

Inconel 718 round bars are widely used in aerospace engine components, oil and gas wellhead equipment, power generation turbines, chemical processing plants, cryogenic tanks, and nuclear reactor parts.

What temperature can Inconel 718 withstand?

Inconel 718 maintains excellent tensile and yield strength up to approximately 700°C (1300°F) and retains good toughness even at cryogenic temperatures, making it suitable for both extreme cold and elevated-heat applications.

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