Comparison of Inconel 600 and 718 fasteners

01.

Due to its age-hardening properties and high yield strength, Inconel 718 fasteners offer significantly higher strength, making them more suitable for high-stress, high-temperature applications up to 650°C (e.g., jet engines). Inconel 600 fasteners possess excellent corrosion and oxidation resistance, making them ideal for corrosive, high-temperature environments up to 1175°C (e.g., chemical and nuclear applications). However, Inconel 600 cannot be hardened by heat treatment; its strength primarily relies on cold working.

02.

What is the strength of Inconel 718 bolts?

185-220 ksi

Inconel 718 is twice as strong as its counterpart, Inconel 625, and is renowned for its exceptionally high strength (tensile strength of 185-220 ksi) after age hardening. Inconel 718 bolts maintain their strength even under pressures and temperatures up to 1300°F (700°C).

Inconel 600 fasteners (such as bolts, nuts, and screws) are high-performance connectors made of a nickel-chromium-iron alloy (Inconel 600), specifically designed to provide reliable connections in high-temperature, highly corrosive environments. They inherit the alloy's excellent oxidation resistance, creep resistance, and superior resistance to chloride stress corrosion cracking at temperatures up to approximately 1150°C. They maintain fastening force and structural integrity for extended periods in harsh conditions such as chemical, nuclear power, marine, and heat treatment equipment. They are a top-tier solution for connecting critical equipment components under extreme conditions that stainless steel cannot withstand, but their material and manufacturing costs are significantly higher than ordinary fasteners.

Inconel 718 fasteners are high-strength connectors made of a precipitation-hardening nickel-based superalloy (Inconel 718). Their core feature is the addition of elements such as niobium and molybdenum, resulting in exceptional strength, creep resistance, and fatigue resistance at high temperatures (up to approximately 700°C) while maintaining good corrosion resistance. It is designed specifically for fields such as aircraft engines, aerospace structures, high-performance racing cars, and oil and gas, which have extreme mechanical performance and high-temperature stability requirements for connectors. It can maintain reliable locking force under severe vibration, high stress, and thermal cycling environments, making it the top choice for dealing with the most demanding structural connection challenges. Its manufacturing and heat treatment processes are complex and costly.

600/718 Inconel ASTM B166 Fasteners Equivalent Grades

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
Inconel 600	2.4816	N06600	NCF 600	NA 13	МНЖМц 28-2,5-1,5	NC15FE11M	NiCr15Fe
Inconel 718	2.4668	N07718	-	-	-	-	-

Chemical Composition of Inconel 600/718 Industrial Fasteners

Grade	C	Mn	Si	S	Cu	Fe	Ni	Cr
Inconel 600	0.15 max	1.00 max	0.50 max	0.015max	0.50 max	6.00 – 10.00	72.00 min	14.00 – 17.00
Inconel 718	0.08 max	0.35 max	0.35 max	0.015 max	0.30 max	-	50.00 - 55.00	17.00 - 21.00

Mechanical Properties Of ASME SB166 Inconel 600/718 Bolts & Nuts

Element	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
Inconel 600	8.47 g/cm3	1413 °C (2580 °F)	Psi – 95,000 , MPa – 655	Psi – 45,000 , MPa – 310	40 %
Inconel 718	8.2 g/cm3	1350 °C (2460 °F)	Psi – 1,35,000 , MPa – 930	Psi – 75,000 , MPa – 482	45 %

Feature	Inconel 600	Inconel 718
Strengthening Method	Cold working only	Precipitation-hardenable (age-hardenable)
Tensile Strength	Lower (e.g., ~655 MPa)	Much higher (e.g., ~930-1530 MPa)
Yield Strength	Lower (e.g., ~255 MPa)	Significantly higher (e.g., ~510-1330 MPa)
Max Service Temperature	Up to 1175°C	Up to 650°C
Primary Application	High-temperature corrosion and oxidation resistance in chemical, nuclear, and heat-treating industries	High-strength, high-temperature stress applications in aerospace and turbines
Hardness	Softer, must be strengthened by cold work	Much harder and stronger