A Ni-Cr alloy known for its corrosion resistance and high temperature stability

• Good corrosion resistance at elevated temperatures
• High temperature stability up to 2200°F (982°C)
• High strength material with excellent toughness at elevated temperatures
• Inconel grades: 600, 601, 625, 686, 718, 725, X750
• In-depth insight on Alloy 625 and Alloy 718
• Inconel hex head cap screw features and benefits
• Datasheets available on Inconel 625 and Inconel 718

Inconel® hex head cap screws, like Inconel 600, 601, 625, 686, 718 & 725 screws, are a family of nickel-chromium-molybdenum alloys used for their high strength at elevated temperatures and good corrosion resistance. Because of its high thermal stability, Inconel can be used in service temperatures ranging from cryogenic to 2200°F (982°C). The high alloy content of Inconel screws enable it to withstand a wide variety of severe corrosive environments. In mild environments, such as the atmosphere, sea water, neutral salts, and alkaline media, there is almost no attack to Inconel hex head cap screws. In more severe corrosive environments the combination of nickel and chromium provides resistance to oxidizing chemicals, whereas the high nickel and molybdenum contents supply resistance to nonoxidizing environments.

Because Inconel hex head cap screws offer a good balance of corrosion resistance, temperature stability, toughness and strength they are often a material of choice for chemical processing, aerospace, marine, electronics and oil & gas.

The most commonly used grades of Inconel nickel alloy hex head cap screws are Inconel 625 and Inconel 718. Gain more insight on these two grades by accessing our Inconel 625 and Inconel 718 overviews or by contacting our engineering experts.

Resources: Inconel Torque Spec, Inconel 625 screws, Inconel 718 screws

Screw Types: 12 Point Screws, Button Head Cap Screws, Flat Head Screws, Hex Cap Screw, Pan Head Screws, Set Screws, Socket Head Cap Screws, Tamper Resistant Security Screws, Torx Screws, Vented Screws

Inconel Hex Head Cap Screw Features and Benefits

It is important to differentiate between a Inconel hex head cap screw and hex head bolt. Often people assume they are the same, but they are actually very different fasteners in terms of how they are manufactured, as well as from an application perspective. Regardless of your choice, Inconel hex heads offer strong, stable joints because of their large head service.

The Hex Comparison

Inconel Hex Head Cap Screw Advantages  

The most important feature of a Inconel hex head cap screws is that it has a larger bearing surface area which provide better clamping pressure than other type of fastener such as a socket head cap screw. Additionally, since debris build up is less of an issue with this style of fastener verses a socket head cap screw, they are ideal of dirty applications where particles could clog up a socket. Though Inconel socket heads are typically used for tight access applications, hex heads can be a better choice when there is only side clearance available for tightening. 

Common Inconel Screw Grades

Inconel 600 

Alloy 600, UNS N06600, is a nickel-chromium alloy with good carburization and oxidation resistance through 2000°F. The alloy has long been used in the heat treating industry and Inconel 600 has useful resistance to dry Cl2 and HCl gases at moderately elevated temperatures. 

Inconel 600 Specifications: AMS 5540, AMS 5665, ASME SB 166, ASME SB 167, ASME SB 168, ASTM B 166, ASTM B 167, ASTM B 168, EN 2.4816, UNS N06600, Werkstoff 2.4816

Inconel 601 

Inconel 601, UNS N06601, is highly resistant to oxidation through 2200°F even under severe thermal cycling. The alloy has good high temperature strength, and retains its ductility after long service exposure. Inconel 601 alloy has good hot corrosion resistance under oxidizing conditions. 

Inconel 601 Specifications: AMS 5715, AMS 5870, ASME SB 167, ASME SB 168, ASTM B 167, ASTM B 168, EN 2.4851, UNS N06601, Werkstoff 2.4851

Inconel 625 

Inconel 625, UNS N06625, is the workhorse of the Inconel family and is one of the most common grades. It exhibits high creep-rupture strength and is oxidation resistant to 1800°F (982°C). Inconel 625 has excellent resistance to hot seawater, scrubber environments and reducing acids and this alloy resists a wide range of severely corrosive environments and is especially resistant to pitting and crevice corrosion. 

Inconel 625 Specifications: AMS 5666, AMS 5837, ASME SB 443 Gr 1, ASME SB 446 Gr 1, ASTM B 443 Gr 1, ASTM B 446 Gr 1, EN 2.4856, ISO 15156-3, NACE MR0175-3, UNS N06625, Werkstoff 2.4856

Inconel 686 

Alloy 686, UNS N06686, is designed for outstanding corrosion resistance in a wide range of severe environments. The alloy is used in the most severe environments encountered in chemical processing, pollution control, pulp and paper production, and treatment of industrial and municipal waste. 

Inconel 686 Specifications: ASTM B 462, ASTM B 564 / ASME SB 564, ASTM B 574 / ASME B 574, DIN 17752, DIN 17753, DIN 17754

Inconel 718 

Inconel 718, UNS N07718, is the most common grade of the hardenable Inconels. This precipitation-hardened nickel-chromium alloy combines outstanding corrosion resistance and high strength at elevated temperatures. The alloy is a about 2x as strong as Inconel 625 having excellent creep-rupture strength at temperatures to 1300°F (700°C) and usable up to 1800°F (982°C). Inconel 718 is often used in gas turbines, rocket motors, spacecraft, nuclear reactors, pumps, and tooling. 

Inconel 718 Specifications: AMS 5596, AMS 5662, AMS 5663, ASME Case 2222-1, ASME SFA 5.14, ASTM B 637, ASTM B 670, EN 2.4668, GE B50TF14, GE B50TF15, UNS N07718, Werkstoff 2.4668

Inconel 725 

Alloy 725, UNS N07725, nickel-chromium-molybdenum-niobium age-hardenable alloy that has essentially the same corrosion resistance as Inconel 625, but with a strength of that is twice that of annealed Inconel 625. The strength of this alloy is developed by heat treatment to achieve high ductility and toughness. The alloy is resistant to hydrogen embrittlement and stress-corrosion cracking as well. 

Inconel X750 

Alloy X-750, UNS N07750, is a precipitation hardened alloy known for its corrosion resistance and high temperature oxidation resistance up to temperatures of 1300°F.  This alloy is similar to Alloy 600 but made precipitation hadenable with  the addition of titanium and aluminium. 

Inconel X750 Specifications: ASTM B 637/ASME SB 637; ISO 9723-9725; SAE AMS 5667-5671 and 5747; EN 10269

 Mechanical Data

Inconel Corrosion Data