ASTM A1014 Inconel 718 Stud Bolts | UNS N07718 High-Temperature Bolting
ASTM A1014 Inconel 718 stud bolts are precipitation-hardened nickel-chromium alloy fasteners designed for high-strength bolting at elevated temperatures.
The material is identified as UNS N07718, commonly known as inconel alloy 718 / Alloy 718, and has the European material number 2.4668.
ASTM A1014 / A1014M specifically covers UNS N07718 bolting material and bolting components for high-temperature service. The alloy combines very high tensile and yield strength with good corrosion resistance, oxidation resistance, fatigue strength and stress-rupture performance.
Typical applications include gas turbines, pressure equipment, high-temperature valves, offshore equipment, subsea systems, aerospace equipment and critical flange connections.
ASTM A1014 UNS N07718 Overview
| Item | Specification |
|---|---|
| Bolting Standard | ASTM A 1014/ A1014M |
| Material | Alloy 718 / Inconel 718 |
| UNS | N07718 |
| EN / W.Nr. | 2.4668 |
| Alloy Type | Precipitation-Hardenable Ni-Cr-Fe Alloy |
| Tensile Strength | 185 ksi / 1275 MPa min |
| Yield Strength | 150 ksi / 1035 MPa min |
| Typical Threads | UNC, UNF, 8UN |
| Stud Dimensions | ASME B18.31.2 or Project Drawing |
| Typical Service | High-Temperature / High-Strength Bolting |
What Is ASTM A1014?
ASTM A1014 is a dedicated specification for precipitation-hardening UNS N07718 bolting used in high-temperature service.
It controls important requirements including:
- Material chemistry
- Melting practice
- Solution heat treatment
- Precipitation aging
- Mechanical properties
- Hardness
- Stress-rupture performance
- Thread manufacture
- Microstructure
- Testing and certification
ASTM A1014 should therefore be distinguished from a general Alloy 718 raw-material specification.
Material supplied as ASTM B637 UNS N07718 bar or forging stock is not automatically finished ASTM A1014 bolting. Finished stud bolts must meet the applicable A1014 processing and testing requirements.
Inconel 718 / UNS N07718
UNS N07718 is a nickel-chromium-iron alloy containing significant additions of niobium and molybdenum together with titanium and aluminum.
The alloy develops high strength through precipitation hardening.
Key characteristics include:
- Very high tensile strength
- High yield strength
- Good fatigue resistance
- Excellent stress-rupture performance
- Good oxidation resistance
- Good corrosion resistance
- Good strength retention at elevated temperature
- Good performance at cryogenic temperatures
These properties make Alloy 718 particularly useful for critical bolting where conventional stainless or alloy steel fasteners do not provide sufficient strength.
Chemical Composition
Typical ASTM A1014 UNS N07718 chemistry includes:
| Element | Requirement |
|---|---|
| Nickel, Ni | 50.0–55.0% |
| Chromium, Cr | 17.0–21.0% |
| Iron, Fe | Balance |
| Niobium + Tantalum | 4.75–5.50% |
| Molybdenum, Mo | 2.80–3.30% |
| Titanium, Ti | 0.65–1.15% |
| Aluminum, Al | 0.20–0.80% |
| Carbon, C | 0.08% max |
| Manganese, Mn | 0.35% max |
| Silicon, Si | 0.35% max |
| Phosphorus, P | 0.015% max |
| Sulfur, S | 0.015% max |
| Copper, Cu | 0.30% max |
| Boron, B | 0.006% max |
Actual chemistry is reported on the Material Test Certificate.
Mechanical Properties
ASTM A1014 requires high mechanical strength after precipitation heat treatment.
| Property | Requirement |
|---|---|
| Tensile Strength | 185 ksi / 1275 MPa min |
| Yield Strength, 0.2% Offset | 150 ksi / 1035 MPa min |
| Elongation | 12% min |
| Reduction of Area | 15% min |
| Hardness | 331–444 HBW |
The standard also includes elevated-temperature tensile and stress-rupture requirements.
This combination of high strength and elevated-temperature performance is one of the main reasons ASTM A1014 is selected for critical bolting.
Heat Treatment
ASTM A1014 uses controlled solution treatment followed by precipitation aging.
Typical processing includes:
Solution Treatment:
1725–1850°F / 940–1010°C
followed by controlled cooling.
Precipitation Aging:
approximately 1325°F / 720°C, followed by controlled furnace cooling to approximately 1150°F / 620°C and further aging.
The precipitation treatment develops the high tensile, yield and stress-rupture properties required for ASTM A1014 bolting.
Stress-Rupture Performance
ASTM A1014 includes stress-rupture testing as part of its high-temperature qualification.
Typical test conditions include:
- Temperature: 1200°F / 650°C
- Applied Stress: 100 ksi / 690 MPa
- Minimum Rupture Time: 23 hours
- Minimum Elongation: 5%
This requirement helps distinguish ASTM A1014 from general-purpose nickel-alloy fastener specifications.
ASTM A1014 Stud Bolt Types
Available configurations include:
- Fully Threaded Stud Bolts
- Flange Studs
- Continuous-Thread Studs
- Double-End Studs
- Tap-End Studs
- Hex Bolts
- Custom High-Temperature Fasteners
Stud bolts can be manufactured according to project drawings or applicable dimensional standards.
ASME B18.31.2 Stud Bolts
Inch-series ASTM A1014 stud bolts can be supplied to ASME B18.31.2 dimensional requirements when specified.
Common thread series include:
- UNC
- UNF
- 8UN
Unified threads are typically specified according to ASME B1.1.
Typical flange bolting sizes may include:
- 1″-8UNC
- 1-1/8″-8UN
- 1-1/4″-8UN
- 1-1/2″-8UN
- 1-3/4″-8UN
- 2″-8UN
Custom diameters, lengths and thread configurations can be manufactured according to project requirements.
Inconel 718 Stud Bolts and Nuts
ASTM A1014 stud bolts can be supplied with matching UNS N07718 hex or heavy hex nuts where required by the project specification.
A typical bolting assembly may consist of:
- 1 ASTM A1014 UNS N07718 Stud Bolt
- 2 Matching Alloy 718 Heavy Hex Nuts
Nut dimensions, mechanical properties, heat treatment, thread fit and certification should be clearly stated in the purchase order.
Using the Alloy 718 material name alone does not confirm compliance with ASTM A1014 finished-bolting requirements.
ASTM A1014 vs ASTM B637
ASTM A1014 and ASTM B637 serve different purposes.
| Item | ASTM A1014 | ASTM B637 |
|---|---|---|
| Main Product | Bolting | Bar, Forgings and Forging Stock |
| Material | UNS N07718 | UNS N07718 among other alloys |
| Finished Fastener Requirements | Yes | No |
| Stress-Rupture Bolting Requirements | Yes | Material/Product Dependent |
| Thread Requirements | Included for Bolting | Not a Stud Bolt Standard |
For a critical high-temperature stud bolt, the purchase order should specify ASTM A1014 rather than relying only on ASTM B637 raw material.
Typical Applications
ASTM A1014 Inconel 718 stud bolts are commonly used in:
- Gas Turbines
- Steam Turbines
- High-Temperature Valves
- Pressure Equipment
- Heat Exchangers
- Offshore Equipment
- Subsea Equipment
- Oil and Gas Processing
- Chemical Processing
- Nuclear Equipment
- Aerospace Systems
- Critical High-Strength Flange Connections
Inspection and Certification
ASTM A1014 bolting can be supplied with:
- EN 10204 Type 3.1 Certification
- Chemical Analysis
- Tensile Testing
- Yield Strength Testing
- Hardness Testing
- Stress-Rupture Testing
- Elevated-Temperature Testing where required
- PMI
- Thread-Gauge Inspection
- Dimensional Inspection
- Heat-Treatment Records
- Microstructure Examination
- Third-Party Inspection
- Full Heat / Lot Traceability
How to Order ASTM A1014 Stud Bolts
A complete inquiry should include:
- ASTM A1014 / A1014M
- UNS N07718
- Stud diameter
- Overall length
- Thread series and pitch
- Thread class
- Nut requirement
- Dimensional standard
- Quantity
- Certification
- Additional testing
- Third-party inspection requirements
Example 1
ASTM A1014 UNS N07718 Inconel 718 Stud Bolt, 1-1/2″-8UN × 12″, Fully Threaded, EN 10204 3.1
Example 2
ASTM A1014 Alloy 718 Stud Bolt, 1-1/4″-8UN × 10″, ASME B18.31.2, with 2 Matching Heavy Hex Nuts
Example 3
ASTM A1014 UNS N07718 Stud Bolt Assembly, 2″-8UN, Custom Length, PMI, Stress-Rupture Test and Third-Party Inspection
Frequently Asked Questions
What is ASTM A1014?
ASTM A1014 is a bolting specification specifically for precipitation-hardened UNS N07718 material used in high-temperature service.
Is ASTM A1014 the same as Inconel 718?
ASTM A1014 uses UNS N07718, commonly known as Inconel 718 / Alloy 718. ASTM A1014 additionally controls the processing, heat treatment, mechanical properties and testing required for finished bolting.
Is ASTM B637 the same as ASTM A1014?
No. ASTM B637 covers nickel-alloy bars, forgings and forging stock, while ASTM A1014 is specifically intended for UNS N07718 high-temperature bolting.
What is the tensile strength of ASTM A1014 bolting?
The minimum room-temperature tensile strength is 185 ksi / 1275 MPa.
Can ASTM A1014 studs use 8UN threads?
Yes. 8UN threads can be supplied for inch-series flange stud bolts when specified.
Related High-Performance Bolting Products
- ASTM A453 Grade 660 / Alloy A286 Stud Bolts
- ASTM A193 B8M Class 2 Stud Bolts
- ASTM A1082 Super Duplex Stud Bolts
- UNS N06625 Alloy 625 Stud Bolts
- UNS N08825 Alloy 825 Stud Bolts
- ASME B18.31.2 Stud Bolts
- 8UN High-Strength Stud Bolts
Packing Information:
1.Carton Size: 25*16*25CM
2.Wooden Pallet/Case Size: 110*90*80CM
3.Color Printed Box&Cartons can be made per customers’ desire.
ASTM A1014 Inconel 718 Stud Bolt Supplier
We manufacture and supply ASTM A1014 / A1014M UNS N07718 stud bolts and high-strength fasteners for high-temperature, offshore, subsea and critical pressure-equipment applications.
Available products include fully threaded studs, flange studs, double-end studs, 8UN stud bolts, matching nuts and custom Alloy 718 fasteners.
For quotation, please provide the diameter, length, thread, nut requirement, quantity, certification and inspection requirements.
