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Low melting point alloys & their uses

Posted February 15th 2017

William Rowland Limited is able to produce a wide range of low melting point alloys at our foundry in Birmingham. We can produce to known industry specifications or alloys that are tailored to meet our customers’ specific requirements.

Fusible alloys

A fusible alloy is essentially a type of metal alloy which can be fused with ease. These metal alloys can be melted at temperatures that are relatively low. They are typically eutectic alloys, meaning they have a sharp melting point.

Fusible alloys are often used as the term to describe alloys that have a melting point which is below 183 degrees Celsius.

What are fusible alloys used for?

Fusible alloys are irreplaceable in a range of applications where their low melting point is fundamental:

  • Tube and profile bending
  • Work holding of delicate or irregular pieces
  • Fusible cores for plastic or composite moulding techniques
  • Fusible plugs for boilers and pressure vessels
  • Fusible safety devices for fire prevention such as sprinklers
  • Lens blocking
  • Rapid prototyping of press tools

 

Most low melting point alloys are bismuth based and William Rowland can produce a range of quality bismuth-based alloys to exacting specifications, including:

WR 47                   Lens alloy – used for Lens blocking

WR 58                   Lens alloy – used for Lens blocking

WR 70                   Bend alloy – used for Tube and profile bending

WR 137                 Press alloy – used for Work holding, fusible cores

Bend alloy – WR 70

One type of low melting point alloy William Rowland produces is bend alloy (WR 70).

Bend alloy is one of the most extensively used alloys in industry due to its primary characteristic of expansion on solidification from the molten state. This makes bend alloy an ideal material to support metal tubing with thin walls during bending operations.

The alloy has a sharp melting point of 70 degrees Celsius and can consequently be melted with hot water.

Lens alloy – WR 47 & WR 58

Lens alloys are part of the group of bismuth-based ‘fusible’ alloys. Indium is added to the alloy in order to give it a considerably lower melting point. Lens alloys are eutectic alloys, characteristically possessing a sharp melting point at 58 or 47 degrees Celsius. This low temperature is ideal for acting as a ‘button’ or holding medium in the grinding of lenses.

Possessing stable characteristics, and being easy to melt, lens alloy can be reused repeatedly if required.

Primary use of lens alloy

The primary use of lens alloy is in grinding operations when it proves invaluable in holding glass or plastic lenses. WR 47 is best suited for plastic or composite lenses, whilst WR 58 is used primarily for glass. Due to its low melting properties, lens alloy is also a suitable component in the fuses of safety equipment. Lens alloy can also be effective in proof casting.

Press alloy – WR 137

Press alloy is considered close to eutectic having a relatively sharp melting point at 138°C. It has greater hardness and tensile strength than other fusible alloys and lends itself to anchoring, work-holding and low volume presswork. WR 137 exhibits minimal expansion upon solidification from the molten state, this is useful for holding machined parts where shrinkage or expansion may deform the finished part.

Casting alloy

Casting alloys are a range of low temperature alloys based on tin, lead or bismuth that are suitable for production of jewellery, models, figures, artwork, collectibles, ornaments and memorabilia.

William Rowland produces many different grades of casting alloy to suit the customer’s process and production requirements, however we will also produce to a customer’s individual specification. Our casting alloys are suitable for the professional or hobbyist and we produce many grades that are safe and easy to work with using only the minimum of basic equipment.

Lead-free pewter alloys are popular for jewellery, artwork and collectibles where reproduction of fine detail and cast finish are important, as well as being safe for human contact . These alloys are commonly high in tin and alloyed with copper and antimony. As-cast finish is very good and cast objects polish very well to a silver lustre.

For applications in which lead can be tolerated, the range of alloys is extensive, generally providing cheaper alloys but ones which can be tailor-made for specific purposes such as thin or bulky items, reproducing fine detail, malleability or achieving a particular surface finish. These alloys commonly contain tin, lead and bismuth but may also contain antimony and zinc.

William Rowland casting alloys are suitable for a range of casting techniques such as centrifugal and gravity casting into rubber or silicon moulds.

Contact us today for any requirements of low melting point alloys.

LMPA

The Iron Bridge

Posted February 14th 2017

The Iron Bridge was constructed in 1777, and first opened for use in 1781. It is located in Shropshire, over the River Severn and is still intact today. The first arch bridge to be made of cast iron, the Iron Bridge spans 100 feet and 6 inches and was a revelation to for trading when it was first constructed. It even gives name to the village that lies at the foot of it – Ironbridge.

Bridges had previously been most commonly made with stone or wood, and whilst there had been iron bridge designs and even several attempts to build one, the Iron Bridge was the first cast iron bridge to be erected. Shropshire itself was at the centre of the iron industry and the River Severn used as a key trading route. The Severn Gorge, however, presented an obstacle that became increasingly restraining to trade.

In 1773, an architect named Thomas Farnolis Pritchard approached his friend John Wilkinson, an ironmaster, with the revolutionary idea of building a bridge over the river, made of cast iron. This would link the parishes of Benthall and Madley and create a route that traversed the river, making it easier and quicker to transport goods. By 1776, the pair had not only raised money for their project, but received a Royal Assent     to construct their bridge, although there was some initial uneasiness about the use of iron, rather than more familiar materials.

Once the specifics of the bridge had been agreed, construction was able to begin in 1777. This was a complex procedure as there are over 1700 individual components that make up the bridge, with five large cast iron ribs giving the support. 378 tons of iron were used and the end cost of £6000, became almost double what had first been estimated. Nevertheless, the structure opened on New Years Day of 1781, creating a landmark moment in British history. Unfortunately, only one month after construction had begun, Thomas Farnolis Pritchard passed away and was never able to see his finished idea in real life.

An icon of Britain’s industrial past, the Iron Bridge was declared a UNESCO World Heritage Site 1986. Although it still stands, it was closed to vehicles in 1934. This year, there is £1.25m conservation project due to be carried out that will repair some of the damage and strain caused to the ironwork over the year, and ensure the bridge remains standing.

Iron Bridge

What is the strongest metal in the world?

Posted February 5th 2017

Metals can have many different qualities, and strength is an important one for several industries. Metal alloys, are often stronger than pure metals and there are different types of strength that vary in importance depending on what they are being used for.

Because they are fit for different purposes, we can cite several metals as being amongst the strongest. The first is steel, which is an alloy of iron and carbon. Steel is used to make everything from cutlery to skyscrapers and is one of the most common materials we use today. Steel is made by heating iron ore, in order to remove any impurities, and then adding carbon (although other elements may be used). There are different ways to test the strength. Tensile strength, for example, measures the amount of pulling stress that can be administered before the steel falls or breaks, this is usually achieved by pulling the steel in vices before it eventually snaps. Compressive strength, on the other hand, is tested by applying pressure to the steel until it breaks in order to determine the level of pressure it is able to withstand. Compressive strength is particularly important if the steel is to be used in construction.

Titanium, is a metal that is well noted for its high tensile strength to density ratio – the highest of any metallic element. It is often alloyed with other materials, including iron and aluminium, to produce strong and lightweight alloys that are popular for use in the aerospace industry. Two thirds of all titanium alloys produced are used in the manufacture of aircraft parts. Titanium also has an extraordinarily high resistance to corrosion making it ideal for use in propeller shafts.

Tungsten, one of the rarer metals to be found, is very hard and possesses the highest tensile strength of pure metals. It is very brittle and hard to work in its raw form, but if made very pure it is harder than most steels and can be made malleable enough to work. It can also be further enhanced when alloyed with steel. Tungsten is mostly used to produce hard materials, most commonly tungsten carbide. Tungsten carbide can be used to make Knives, drills and circular saws, and industries including construction and metalworking rely on tools made from tungsten carbide.

Strongest Metals in the World

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