marine engineering

Mastering the “Workhorse” otherwise known as Inconel 718

3/8 UNF 12pt Bolts manufactured from Inconel 718

In the world of precision engineering, the term “workhorse” is rarely used for something delicate. It’s reserved for materials that survive where others fail. Inconel 718 has firmly established itself as that indispensable staple, particularly in the production of high-performance 3/8 UNF 12pt bolts.

Whether you’re navigating the rigorous standards of the UK’s Aerospace sector or optimising high-pressure systems in the North Sea, the demand for corrosion-resistant fixings that can handle the heat has never been higher.

A Brief History

Inconel was invented in the early 1930’s by a team of scientists at the International Nickel Company (INCO) in Herefordshire, England. The trademark for Inconel was first registered in December 1932. The alloy’s development was largely driven by the need for materials that could withstand the extreme heat and pressure of early jet engines, such as the one co-designed by Sir Frank Whittle.

The Superalloy Standard

Inconel 718 is a nickel-chromium-based superalloy designed to maintain its structural integrity in environments that would cause standard stainless steel to soften or oxidise.

Offering a yield strength that competes with the toughest steels, but with the added benefit of heat resistance. It remains functional at temperatures up to 700°C, making it the go-to for exhaust manifolds, turbine components, and nuclear reactors.

From saltwater to aggressive chemical processing, Inconel 718 provides a formidable barrier against pitting and stress-corrosion cracking.

The “Workhorse” Challenge

Inconel is notoriously difficult to manufacture. Its high shear strength and tendency to work-harden, mean it fights back against cutting tools.

Only high-grade carbide or ceramic tools with specialised coatings can survive the abrasive nature of this alloy.

Inconel has poor thermal conductivity, meaning heat stays at the cutting edge. Precision cooling is essential to prevent micro-cracking and ensure the finished bolt meets ISO standards.

Managing feed rates is a balancing act. Too fast and the tool breaks, too slow and the material hardens beyond the point of being workable.

Applications Across the UK Industry

We are manufacturing various Inconel parts, often seeing them move to beyond niche aerospace projects and into broader industrial sectors, such as –

Renewable Energy: Fastening components in next-gen offshore wind turbines.

Automotive: High-stress bolts for performance engines and electric drivetrain housings.

Marine Engineering: Subsea fixings where reliability is the only option against the Atlantic’s corrosive environment.

At the junction of metallurgy and craftsmanship, we specialise in the difficult jobs. Our latest batch of 3/8 UNF 12pt Inconel 718 bolts represents the pinnacle of current fastener technology. Built to endure, designed to perform.

If you’re looking for expert advice and quality manufacturing, our teams are ready to assist.

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