High Strength Copper Alloys

Nickel and copper alloy in any ratio from 0-100% of either metal. The simplest copper-nickel alloys contain around 10% nickel, which increases the strength, abrasion and galling resistance of copper while keeping its high resistance to biofouling.

The origins of high-strength copper-nickel

The first high-strength copper-nickel alloys were developed in the 1930s, using an addition of aluminium to create a fine precipitate that improves yield strength. Langley Alloys optimised this approach, developing several new alloys under the Hidurax name from 1939 onwards.

Hiduron^® 130

Hiduron^® 130 was originally known as Hidurax Special, developed as a high-strength, corrosion-resistant alloy for naval applications such as seals, shafts, submarine control planes and winch components. Aluminium is the key strengthening element in Hiduron^® 130 (2.1504, DTD 900/4805, C72400, Cuni14Al3), forming a finely dispersed gamma-prime nickel-aluminium precipitate that strengthens the alloy much as it does Alloy K-500. Because these precipitates form through a carefully controlled forging process and age naturally during cooling, no further heat treatment is needed - making it one of the highest strength copper alloys commercially available.

Hiduron^® 191

Hiduron^® 191 (DEF STAN 02-835, NES 835, DOD-C-24676, EB4223A, UNS C72420) was developed in the 1960s as a complement to Hiduron^® 130, to improve impact toughness. Up to 4.5% manganese is added to increase solid-solution strengthening, while the aluminium is moderated to reduce the extent of precipitation strengthening. The gain in impact strength comes with a decrease in yield strength as a consequence.

Subsea applications

Offshore oil and gas exploration took Hiduron^® 130 beyond its original naval and aerospace uses. High strength and resistance to fouling clearly help in subsea service, but galling resistance has been particularly relevant in subsea connectors and stab plates. Metal components in contact for extended periods can gall, where the surfaces micro-weld at high points under the influence of load and time; the parts can then seize or be damaged when disconnected or actuated. The physical and mechanical properties of Hiduron^® 130, together with its resistance to fouling, suit it to wet-mate electrical and hydraulic connectors that must operate for long periods before immediate, safe disconnection.

Alternatives

Once the original Langley Alloys patent lapsed, other manufacturers exploited the basic composition. Alloys meeting the generic DIN 2.1504 caption include Nibron Special by Columbia Metals, Hardibron by Lebronze Alloys and CAL T-100 by Copper Alloys.

The broad range of useful properties in the Hiduron^® copper nickel alloys is hard to better. Where high strength is the priority, copper beryllium alloys have been used (for instance C17200, C17300 and C17400), but inhaling the dust or fume generated when machining and fabricating copper beryllium (CuBe) can cause serious lung conditions, so it has fallen from favour in recent years.

A more recent family of interest is copper-nickel with additions of tin. These copper-based spinodal alloys use an unusual metallurgical feature to reach very high strength: the forged bar is age-hardened, which drives a form of chemical segregation called spinodal decomposition, forming two new phases. Alloys such as Toughmet 3 (C72900) by Materion Corporation are listed by some OEMs as alternatives to Hiduron^® 130, though this product is appreciably more expensive.

Developed more than 70 years ago, the Hiduron^® range - including Hiduron^® 130 and Hiduron^® 191 - has provided market-leading performance, with a combination of physical and mechanical properties that remains unrivalled.

We stock Hiduron^® 130 from ½" (12.7mm) to 8" (203.2mm) diameter solid bar, and routinely produce bespoke forged components with in-house testing and inspection to customer-specific standards.