Read the latest technical insight from Columbia Metals to deepen your understanding of advanced performance alloys.
If you have any questions on this content, or suggestions for future blog posts, please get in touch with us at technical@columbiametals.co.uk.
Within the Monel family of nickel-copper alloys there are two particular alloys, Alloy 400 and Alloy K500, that appear outwardly to be very similar. An in-depth examination reveals there are differences between the two. Further explanation of these differences can prove of benefit in issues of material selection. In this post we will look at the two alloys and compare and contrast their metallurgical properties.
Alloy 400 and Alloy K500 are both nickel-copper alloys containing approximately 65% nickel and 30% copper. The chemical composition of Alloy K500, however, includes 3% aluminium and 0.5% titanium.
| Ni | Cu | Al | Fe | Mn | Ti | |
|---|---|---|---|---|---|---|
| Alloy 400 | 63 min | 28-34 | – | 2.5 max | 2.0 max | – |
| Alloy K500 | 63 min | 27-33 | 2.30-3.15 | 2.0 max | 1.5 max | 0.35-0.85 |
The two alloys also have different strengthening methods. Alloy 400 is solid solution strengthened and K500 is precipitation hardened. It is these different strengthening mechanisms that produce the mechanical differences between Alloy 400 and K500. The solid solution strengthening of Alloy 400 gives a lower tensile strength than that of K500 but makes it tougher than K500.
| Alloy 400 <40mm cold worked, stress relieved |
Alloy K500 <25mm cold worked, precipitation hardened |
|
|---|---|---|
| UTS (MPa) | 600 | 1000 |
| 0.2% Proof Strength (MPa) | 415 | 760 |
| Elongation (%) | 20 | 14 |
The different alloying additions impact the cost of each material. The extra alloying additions for K500 have a commensurate effect on the price of the alloy. Alloy 400 is available at a lower price point for a given size while still providing a high tensile strength and maintaining the excellent corrosion resistant properties of K500.
The corrosion behaviour of Alloy 400 and Alloy K500 often finds them gainful employment, particularly in the chemical processing industries. Both alloys provides excellent corrosion resistance, although in some environments Alloy K500 can be susceptible to stress corrosion cracking (for example, hot hydrofluoric acid vapour at tensions close to the alloy’s yield strength). This is not an issue with Alloy 400, which makes it an excellent choice for use in equipment in contact with fluorine, hydrofluoric acid and hydrogen fluoride or their compounds.
| Alloy 400 | Alloy K500 precipitation hardened |
|
|---|---|---|
| Density (g/cm3) | 8.80 | 8.44 |
| Melting Range (oC) | 1300-1350 | 1315-1350 |
| Young’s Modulus (GPa) | 180 | 179 |
| Thermal Conductivity (W/moC) | 180 | 179 |
| Coefficient of Thermal Expansion (μm/moK) | 13.9 x 10-6 | 13.4 x 10-6 |
| Electrical Conductivity (IACS) | 34 | 28 |
The final difference between Alloy 400 and Alloy K500 is the processing route, which can differ depending on size. Columbia Metals stocks Alloy 400 in the cold worked condition up to 55mm diameter, whereas Alloy K500 is cold worked up to 63.5mm diameter.
The choice between these two alloys ultimately depends on a few key factors, summarised below:
21 August 2024
With years of experience hand forging belt buckles, Alex Maughan of Maughan & Co has identified which metal is the perfect fit. Traditionally an advocate of 304 stainless steel, Alex has additionally embraced the aesthetic advantages of Coldur-A®, a silicon bronze available exclusively from Columbia Metals. “This bronze definitely has a particularly rosy colour to […]
Read more1 May 2024
One of the increasingly popular techniques for recreational fishing is known as centrepin fishing, a method that uses a rod, reel and artificial fly. As a professional manufacturer of 10 different centrepin reels, Chris Lythe has intimate knowledge of the right materials to use to land the best catch. For this reason he has been […]
Read more25 May 2023
As an independent watchmaker, David Cottrell maintains a keen eye on metallurgical advances in order to ensure that optimal materials are used in his timepieces. In his search for specialist metallurgical materials, he approached Columbia Metals to obtain some beryllium copper for the production of his balance wheels, a centrally important timekeeping mechanism that functions similarly to […]
Read more25 May 2023
With a lifelong passion for making knives, Clive Witton has relied on Columbia Metals as a supplier of nickel silver for almost 10 years. When embarking on a recent project to make a Drop Point Hunter, a design made famous by legendary American knifemaker Bob Loveless, he naturally looked to Columbia for supplies. The drop point […]
Read more25 May 2023
‘I say ‘tis copper’ – Henry IV, Part I [III, 3] On 20 August 2016 a ‘grand bronze-studded oak door,’ as the Guardian newspaper called it, swung open onto Stratford-upon-Avon’s Chapel Street inviting people into the new gardens of what was once William Shakespeare’s family home and final residence. New Place, as it was called, was a medieval house […]
Read more25 May 2023
It was music to the ears of Columbia Metals when Philip James got in touch in search of nickel silver sheets to make a gong. Nickel silver has unsurpassed sound resonating capabilities and Columbia Metals stocks the alloy in sheet form in several thicknesses. Philip, a musical instrument maker from Bristol, has been passionate about […]
Read more25 May 2023
The opportunity to exhibit at the Chelsea Flower Show – arguably the most famous flower and landscape gardens show in the world – led Gloucestershire-based designer David Murphy to seek the support of Columbia Metals. With almost 30 years’ experience in the creation of one-off garden centrepieces, David required several brass sheets to produce a […]
Read more25 May 2023
For more than 50 years, Gear Services (Letchworth) have been manufacturing a range of 4mm scale model railway wheels under the product name of ‘Ultrascale’. For scale modellers, their product offering fulfils a vital niche in the market and relies on the highest quality materials. “When we started out, the tyres used for the wheels […]
Read more25 May 2023
Interpreting material specifications dating back to the 1940s is a regular part of the work of Hercules Propellers, a specialist aircraft propeller design and manufacturing company based in Gloucestershire. One of their recent assignments was the replacement of critical parts from Spitfire propellers using drawings and specifications from the WW2 era. “The original Rotol drawings […]
Read more25 May 2023
The supply of bespoke motorsport components is the main activity of Loughborough-based O D Engineering. With a proud reputation in motorsport engineering, the company uses only the highest quality materials to ensure maximum reliability for the components it manufactures. “One of our key customers commissioned us to make valve guides using Colsibro®,” outlines Dinesh Parmar, Director […]
Read more24 May 2023
A passion for Rolls-Royce cars and an ambition to perfect the design of cylinder blocks are the twin engines of Kent-based Ameeco Engineering. The company uses C106 copper tubing as part of its Rolls-Royce 20hp cylinder blocks that are now supplied worldwide. The Rolls-Royce Twenty was produced between 1922 and 1929. Designed by Sir Henry Royce, the […]
Read more24 May 2023
The restoration of original MV Agusta racing motorcycles is a passionate interest of Mark Kay, the director of MV Meccanica Verghera. His company has elected to use Colsibro®, a trademark alloy of Columbia Metals, to replace the motorcycles’ original cast iron valve guides. “Having produced replicas of the 1972 3- and 4-cylinder engines we are always […]
Read more24 May 2023
Andrew Edmonds, the proprietor of Compass Marine Yacht Surveys, was tasked with the almost complete rebuild of a 35m long wooden motor yacht dating back to 1942. When Andrew first surveyed the vessel he recommended that all the keel bolts be replaced as many were no longer visible or were very weak. For this application, Andrew […]
Read more24 May 2023
Oliver Valvetek produces an extensive range of needle and ball valves used in hostile subsea environments around the world. The high strength and corrosion resistance offered by Nibron Special®, available only from Columbia Metals, has made this alloy the perfect choice for gate valve override stems designed and manufactured by the company. “We have a longstanding […]
Read more24 May 2023
Contemporary blacksmith Andy Hopper AWCB used Coldur-A®, a proprietary alloy from Columbia Metals, to design a staircase handrail that was awarded the prestigious Tonypandy Cup by the Worshipful Company of Blacksmiths. Andy was initially approached in 2009 to design a staircase handrail for a property with an original Georgian exterior and a modern interior. The property […]
Read more24 May 2023
The use of Coldur-A® for chandelier candle holders at a world famous theatre is one of the more creative applications for this versatile alloy. The Sam Wanamaker Playhouse, the candlelit indoor theatre at Shakespeare’s Globe in London, approached Columbia Metals when searching for a suitable material for exactly this purpose. “Coldur-A® silicon bronze forges well, has a lovely […]
Read more24 May 2023
Guy Croft Racing Engines have specialised material requirements for the build and maintenance of Fiat and Lancia competition engines. For the manufacture of valve guides and seat inserts for a cylinder head, Guy Croft uses Trojan, an extra high strength copper nickel silicon alloy available only from Columbia Metals. Trojan is based on a similar […]
Read more24 May 2023
Swedish manufacturer Tractive AB approached Columbia Metals when searching for a material to replace the need for a protective coating on a critical steel component that was under frequent stress. Using the technical advice and expertise provided by Columbia Metals, allied with the support and responsiveness of the export sales team, a solution was quickly […]
Read more24 May 2023
H I Fraser, headquartered in Sydney, Australia, manufactures products that are used in pneumatic, hydraulic and hyperbaric fluid systems. When the company required a material to manufacture nuts in a gas supply system, they turned to Columbia Metals for the supply of DEF STAN 02-833. “We use this material in a NAB nut in a […]
Read more24 May 2023
In his search for a suitable material for making mirror frames and tables, blacksmith Oliver Dakers relied on the support of Columbia Metals. He required a material that could be both hot and cold forged and was pointed in the direction of Coldur-A®, a trademark alloy of Columbia Metals. “The technical help provided by Columbia’s […]
Read more