Alloy 718 Seamless Pipe

1. Standard: ASTM B163, ASME SB163
2. Size: 1/2''~12'' OD
3. Thickness: SCH5~SCHXXS
4. Equivalent: UNS N07718, WNR.2.4668, Inconel 718

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Product Introduction

Alloy 718 Seamless Pipe is a precipitation-hardened nickel-chromium superalloy. Alloy 718 has become one of the most widely used nickel-based superalloys in the world - accounting for roughly 35% of all superalloy production by weight. Inconel 718 pipe is used in aerospace engines, oil and gas wellheads, nuclear reactors, and chemical processing plants. It is governed by ASTM B775, ASTM B161, AMS 5589, and ISO 15156-3 standards. HT PIPE is a inconel 718 seamless Pipe supplier with 15+ export experience. Contact us for more information and quotes for free!

Chemical Composition of Inconel 718 Pipe

Element	Content (wt%)	Role
Nickel (Ni)	50.00 – 55.00	FCC matrix, base corrosion and thermal stability
Chromium (Cr)	17.00 – 21.00	Oxidation and hot corrosion resistance
Iron (Fe)	Balance	Cost reduction, structural filler
Niobium + Tantalum (Nb+Ta)	4.75 – 5.50	γ″ (gamma double prime) precipitation hardening - primary strengthening phase
Molybdenum (Mo)	2.80 – 3.30	Pitting resistance, solid solution strengthening
Titanium (Ti)	0.65 – 1.15	γ′ (gamma prime) strengthening, grain boundary control
Aluminum (Al)	0.20 – 0.80	Oxidation resistance, γ′ former
Carbon (C)	≤ 0.08	Carbide formation for grain boundary pinning
Manganese (Mn)	≤ 0.35	Deoxidation
Silicon (Si)	≤ 0.35	Deoxidation
Sulfur (S)	≤ 0.015	Controlled to prevent hot cracking
Copper (Cu)	≤ 0.30	Corrosion modifier

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Why does composition matter for buyers?

When procuring Inconel 718 pipe, always request a Mill Test Report (MTR / 3.1 Certificate) confirming the heat chemistry. Deviations in Nb+Ta or Ti content directly affect the volume fraction of hardening phases and can significantly reduce elevated-temperature strength.

Mechanical Properties

Property	Minimum Value	Test Standard
Ultimate Tensile Strength (UTS)	1,240 MPa (180 ksi)	ASTM E8
0.2% Yield Strength (YS)	1,035 MPa (150 ksi)	ASTM E8
Elongation	≥ 12%	ASTM E8
Hardness	36 – 44 HRC	ASTM E18
Impact Toughness (Charpy)	≥ 40 J	ASTM E23
Density	8.19 g/cm³	-
Melting Range	1,260 – 1,336 °C	-
Maximum Service Temperature	700 °C (oxidizing)	-

Available Sizes and Dimensions

Parameter	Typical Range
Outer Diameter (OD)	6.35 mm – 610 mm (¼" – 24")
Wall Thickness	0.5 mm – 50 mm
Length	Random (4–7 m) or cut-to-length
Schedule	SCH 5S, 10S, 40S, 80S, 160, XXS
End Finish	Plain End (PE), Beveled End (BE), Threaded (NPT/BSP)
Surface Condition	Annealed & pickled, bright annealed, electropolished