Gnee Steel's 718 alloy seamless steel pipe manufacturing process begins with the selection of high-quality nickel-based steel billets, which are then hot-extruded and cold-drawn or cold-rolled to achieve precise dimensions. Following this, we employ solution annealing and pickling processes to improve surface finish and stabilize the internal grain structure. Visit this page to learn more about our seamless steel pipe manufacturing process.
Detailed Explanation of ASTM B983 Inconel 718 Pipes
ASTM B983 Inconel 718 tubing (UNS N07718) is a high-strength, corrosion-resistant nickel-chromium-molybdenum alloy tubing designed for harsh, high-temperature environments (up to 700°C). These seamless or welded tubings perform exceptionally well in the aerospace, petrochemical, and oil and gas industries due to their superior creep rupture strength, fatigue resistance, and the ability to undergo age hardening treatments for maximum durability.
Efficiency leap Precision and stability
Adopting high-performance integrated joints,the CRA series can increase the tempo by 25%,and the productivity can reach a new peak;the vibration suppression algorithm is upgraded to achieve a good anti-shaking effect;the full-parameter DH compensation algorithm and TrueMotion algorithm are supported,and the absolute positioning accuracy is 0.2 ~ 0.4 mm under the change of attitude movement,and the curved motion is precise and stable.
Gnee Steel has been dedicated to producing high-quality Inconel 718 seamless steel pipe (SMLS) since 2008. This steel pipe is a high-strength nickel-chromium alloy, precipitation hardened. It contains 50-55% nickel, 17-21% chromium, and fortified with niobium and molybdenum. We manufacture every SMLS pipe strictly according to ASTM B983/ASME SB983 standards. As one of the top high-temperature alloys, Inconel 718 steel pipe is highly valued for its ability to maintain mechanical strength in a high-temperature range from low temperatures to 700°C (1300°F). It is renowned for its excellent fatigue and creep resistance, as well as high-temperature stability. This corrosion-resistant steel pipe is an essential material for gas turbine components, cryogenic storage tanks, and other applications. As a supplier with multiple international certifications, we strictly adhere to a quality management system. Our annual supply capacity is 25,000 tons. Stock orders can be shipped within one week, while production orders require 15-60 days. Our rigorous testing and certification processes ensure that every 718 alloy seamless steel pipe meets the highest industry performance standards for extreme environments.
Characteristics of Seamless Inconel 718 Alloy Pipe
The following four key properties make Inconel 718 tubing the preferred choice for demanding industries:
High-Temperature Strength: Even at extreme temperatures, this tubing maintains its structural integrity and tensile strength. This is due to its unique chemical composition, which allows it to remain stable at temperatures up to 1300°F (700°C), preventing softening or deformation.
Corrosion and Creep Resistance: Inconel 718 alloy tubing exhibits excellent resistance to oxidation and chemical corrosion, while also preventing slow deformation under sustained mechanical stress. This protects piping systems from damage during long-term exposure to harsh, high-pressure industrial environments.
Precipitation Hardening: A specific heat treatment process forms precipitation particles within the tubing, strengthening the metal matrix through an age-hardening process. Compared to other austenitic stainless steels, this process imparts superior hardness and durability to the tubing.
Excellent Machinability: Despite its extremely high strength, Inconel 718 tubing can be successfully welded and formed using appropriate welding techniques and post-weld heat treatment. This ensures the ability to manufacture and securely connect complex components for critical infrastructure.
ASTM B983 Inconel 718 Nickel Alloy Seamless Pipe Tolerance
The table below outlines the standard dimensional tolerances for Inconel 718 nickel alloy seamless tubes as specified in ASTM B983.
| Nominal Outside Diameter in. (mm) |
Outside Diameter in. (mm) |
Permissible Variations % of Thickness of Specified Nominal Wall |
% of Thickness of Specified Minimal Wall | |||
| Plus | Minus | Plus | Minus | Plus | Minus | |
| 1 (25) to 1.900 (48), incl | 0.015 (0.40) | 0.031 (0.79) | 16.0 | 12.5 | 28.5 | 0 |
| Over 1.900 (48) to 4 1/2 (114), incl | 0.031 (0.79) | 0.031 (0.79) | 16.0 | 12.5 | 28.5 | 0 |
| Over 4 1/2 (114) to 6 1/2 (165), incl | 0.047 (1.2) | 0.047 (1.2) | 16.0 | 12.5 | 28.5 | 0 |
| Over 6 1/2 (165) to 9 1/4 (235), incl | 0.062 (1.6) | 0.062 (1.6) | 16.0 | 12.5 | 28.5 | 0 |
| Over 9 1/4 (235) to 14 (356), incl | 0.120 (3.05) | 0.120 (3.05) | 16.0 | 12.5 | - | - |
| Over 14 (356) to 24 (610), incl | 0.20 (5.08) | 0.20 (5.08) | 16.0 | 12.5 | - | - |
Inconel 718 Pipe Equivalent Material
The equivalent designation for Inconel 718 pipe is UNS N07718. It is also known as Werkstoff Nr. 2.4668 and JIS NCF 718. The table below explains these and other globally equivalent designations.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| Inconel 718 | N07718 | - | GH4169 | NCF718 | - | 2.4668 | - |
Application Areas: Key Applications of ASTM B983 Inconel 718
Components manufactured to this standard are indispensable in extreme environments:
Aerospace: Gas turbine engine components, combustion chambers, afterburner components.
Oil & Gas: Downhole tubing, wellhead components, high-pressure valves in hydrogen sulfide (H2S) environments.
Power Generation: Heat exchanger piping in nuclear power plants and supercritical fossil fuel power plants, gas turbine hot gas passage components.
Chemicals: Reactor vessels and piping in highly corrosive processes.
ASTM B983 Inconel 718 Tube Application
Understanding Factors Affecting Inconel 718 Tubing Prices
The price of Inconel 718 tubing is influenced by several factors:
Raw Material Costs: Prices of nickel, cobalt, and niobium on the London Metal Exchange (LME) are a major driver.
Manufacturing Complexity: Smaller diameters, thinner wall thicknesses, and tighter tolerances increase processing difficulty and cost.
Quantity: Mass-produced steel is more cost-effective than small-batch custom-cut steel.
Condition: Aging steel requires additional precision heat treatment, which increases costs.
Testing & Certification: Comprehensive testing (e.g., full ultrasonic testing) and traceable documentation add value and cost.
Market Demand: Global industrial activity significantly impacts supply and prices.
When requesting quotes from Inconel 718 pipe suppliers, providing the complete ASTM B983 specification is the best way to ensure accurate and comparable pricing.
Inconel 718 tube quality assurance and materials testing services
Material Testing Certificates (MTC) for EN 10204/3.1B, EN 10204 3.1, and EN 10204 3.2
Raw Material Certificates
100% Radiographic Testing Report
100% PMI (Positive Material Mixture Analysis)
Heat Treatment Charts
Third-Party Inspection Reports (if required)
Surface Roughness and Dimensional Measurements
Manufacturer's Test Certificates (Impact Testing, Flattening Testing, Rotation Testing, Bending Testing, Hardness Testing, Intergranular Corrosion Testing, Pitting Corrosion Testing, Grain Size Testing, Electrophoresis Testing, Ultrasonic Testing, Heat Treatment)
Laboratory Test Certificates issued by government-accredited laboratories
Gnee Steel also supplies custom Inconel 718 pipes in various sizes and specifications. Please send us your drawings for a quote!
