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    A PLACE FOR

    INSPIRATION AND CHAT

Titanium – why is it so expensive?

Posted May 25th 2017

Titanium is a lustrous, silvery coloured metal that is known to have particularly high strength and low density. It was first discovered in Cornwall in 1791 and takes it names from Greek mythology, after the Titans.

Titanium is used in a wide number of industries including aerospace and jewellery making, and it is valued for being highly resistant to corrosion particularly from chlorine and seawater. But why is it so expensive?

Titanium cannot be extracted by using carbon to reduce the ore as it forms titanium carbide making the metal very brittle. Instead, the extraction process involves several stages that are referred to as the Kroll Process. It is the complexity of this process and the energy expended in production that gives titanium its high market price. The metal must first be turned into a porous form, or titanium sponge as it is sometimes called. From this ingots can be formed by slowly melting the porous metal and these ingots can then be turned into smaller products such as bills, bars, sheets, strips and tubes. Successive re-melting of the metal still produces a high quality metal.

Because titanium has such a high melting point, the temperatures required for this process are extremely high and it is thought that the conversion of the metal to ingots accounts for around 30% of the cost of the entire process. A lot of energy is needed and the process is labour intensive. The strength of titanium means the process is slow and once the finished product is done around 90% of the original material has been lost. When used in the aerospace industry, for example, 1kg of finished titanium has come from almost 11kg.

Titanium

Hyperbaric welding – what is it?

Posted May 18th 2017

Welding is the process of joining together materials, usually metals, but fusing them together through melting the surface points. Two pieces of metal can then be joined to form a single piece. Welding is used for all sorts of reasons from creating metal structures such as bridges and sculptures, to repairing damaged metal structures such as ships.

Hyperbaric welding is a specialist form of welding that requires elevated pressure to work. It is usually performed underwater for this reason. The process can be performed either ‘wet’ or ‘dry’. Wet is when it is performed in the water, and dry is when it takes place in a positive pressure enclosure, or isolation chamber, which gives an increased level of pressure. It is most commonly referred to as hyperbaric welding but when performed in a wet environment it can also be called underwater welding. Hyperbaric welding can be used to repair ships, oil rigs and underwater pipes, and steel is the main material that is used.

Dry hyperbaric welding, as we touched on above, involves the process being carried out in an environment with increased pressure, in a sealed chamber. There will usually be a gas mixture around the chamber. Wet welding is less commonly used and is a skill that less people possess. The welder must also be able to dive, and they are exposed to the risk of electric shock whilst they do this. To prevent this all equipment must be properly insulated and the welding current should be well controlled.

The benefits of this type of welding are that things like oil rigs and ships that are submerged in water can be easily repaired. This makes their maintenance much easier, and more cost effective, as well as enabling the repair to be carried out more quickly than if the structure had to be removed from the water.

Welding

How does a metal detector work?

Posted May 11th 2017

Metal detectors are electronic instruments that are used to detect the presence of metal if it is in close proximity. They can be particularly useful for finding metal that may be underground or hidden and are often used for archaeological purposes.

Different metal detectors can work in different ways, depending on their uses, but in a simple form they usually consist of a transmitter coil, through which electricity flows to create a magnetic field. This turns the metal detector into an electromagnet. By moving the detector, the magnetic field that has been created is moved too and when it comes close to another metal a second magnetic field is created which is what the detector is looking for. There is another coil, called a receiver coil, on the detector that will usually emit a noise when it comes into contact with the magnetic field. Generally, the stronger the magnetic field is the louder the noise will be to indicate how close you are to the metal object.

Metal detectors are also used for security purposes in places such as government buildings and airports. Since the 1970s, metal detectors have been largely used across the world in airports to screen passengers before they board a flight. In addition to this, security officials are often in possession of smaller hand-held devices that can be swept over the body to detect metal.

Anyone can own a metal detector and in England and Wales their use is not prohibited, providing that permission has been granted by the landowner of the area they are to be used on. The only exclusions are if the area in question is a Scheduled Ancient Monument, an SSSI (site of special scientific interest) or falls under the Countryside Stewardship Scheme.

 

Metal Detector

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Metal and Armour

Posted April 18th 2017

Plate armour was historically worn in Europe during the late middle ages. Inspired by the Greeks and Romans, who both used partial armour plates to protect important areas such as their chest, it began to be used widely from the 13th century onwards.

A full set of armour was incredibly complex, consisting of many different parts, and good sets were highly prized. Steel was the main material used, and each individual piece would be shaped and hammered out by hand before being polished to a high shine and often finished with intricate detailing. A typical set of armour could weigh between 15-25kg but a good smith would ensure this was spread throughout the body to enable the wearer to be able to move freely.

Elaborately decorated armour was common for royalty, often called parade armour, and could include fine embossing in different colours. Particularly fine sets would be immortalised in paintings or even kept on show for visitors, such as the Line of Kings at the Tower of London which displays an impressive array of royal armour in the world’s longest running visitor attraction.

Jousting armour was another type, and this was usually substantially heavier than a typical set of plate armour to withstand the heavy blows it was expected to encounter. As the wearer was seated on a horse, there was also less need for free movement, although it still needed to be light enough to be carried by the horse.

As weapons developed and firearms became more commonly used, traditional plate armour became useless for the most part. Modern body armour is now usually made from synthetic fibres, replacing the traditional steel plates. Ballistic vest are usually made from Kevlar since its introduction in the 1970s, although sometimes trauma plates may also be used made of steel or titanium.

Are you allergic to Nickel?

Posted April 5th 2017

Nickel is one of the most commonly used metals in the world, found in everything from currency to house keys. It is also one of the most common allergies with around 10-12% of the world’s population suspected to be affected by this. So what are the signs, and how do you know if this includes you?

Although nickel is found in many everyday items, a reaction can still occur if you have handled nickel before and been fine. A reaction usually appears in the form of a rash wherever the skin has been in contact with nickel, which may take a couple of weeks to subside depending on the severity of the reaction. Common items that can cause a reaction include jewellery, keys, money, watches, belt buckles, clothing fasteners such as zips or buttons, laptops, tablets, phones and even e-cigarettes. Once a reaction has occurred it is likely this will happen again every time the skin comes into contact with the item.

Medical professionals are unsure what it is about nickel that causes this reaction in such a high percentage of people, although some have expressed the opinion that sensitivity to the metal could be genetically inherited, at least in part. Constant exposure to nickel is likely to bring on a reaction, especially if it is close to the skin and you are sweating. This most commonly happens with jewellery but could also happen if you have money or keys in your pocket, or metal parts on your clothes.

A nickel allergy can be simply diagnosed by the doctor by examining the skin, or sending you for a patch test, which involves small amounts of particular allergens being applied to the skin. These areas are then examined for a reaction. There are several creams that can be used to treat a reaction, but the most effective way is to take proper precautions and avoid prolonged contact with items that you know will affect your skin. As nickel is used so prevalently it is pretty much impossible to avoid it altogether but if you are careful you can reduce the risk of a reaction. Handle keys and money as little as possible, taking them out of your pockets and keeping them safely in a bag or purse. Try not to wear jewellery that contains nickel, or ensure it has a very low content, and be careful of the metal parts on your clothes. Different people will have different triggers so it is important to recognise what works for you and what you should avoid.

Nickel Allgery

Metal poisoning – What are the symptoms?

Posted March 21st 2017

Although we come in to contact with various metals all the time in our day-to-day lives, many metals can be toxic to humans and metal poisoning is something that everyone should know how to identify and avoid.

Heavy metal poisoning, is when heavy metals accumulate in the soft tissues of the body. Heavy metals include aluminium, arsenic, barium, lithium, mercury, nickel, silver, tin and many more. The symptoms can vary depending on which metal is present. Below we have outlined some of the most common types of metals associated with heavy metal poisoning, and the symptoms you should look out for.

Arsenic

Symptoms of arsenic poisoning can include abdominal pains, nausea and vomiting and diarrhea, sometimes containing blood. For more severe cases, that develop through long time exposure you should watch out for darkening of the skin, thickening skin and numbness as well as the above. The most common cause of arsenic poisoning is contaminated drinking water, which can be caused by mining, agriculture and toxic waste sites. Unsurprisingly, the areas that are most affected by this are those with a lack of safe drinking water such as Bangladesh and West Bengal. Other countries that have high levels of naturally occurring arsenic in their groundwater include Argentina, Mexico, Chile, Taiwan and Vietnam.

Lead

Lead poisoning is a very real danger for those who work in lead production, and proper precautions should be taken at all times. Symptoms can include abdominal pain, headaches, memory problems and constipation, whilst severe cases can lead to coma and even death. In 2013, lead was attributed to 853,000 deaths and is believed to account for 0.6% of disease in the world.

The effects can vary depending on age and how often one is exposed to lead, and it occurs more commonly in underdeveloped countries. Since concerns were raised about the possible damage caused by exposure to lead in the latter half of the twentieth century, levels of lead found in blood have been declining but low-level lead exposure still occurs.

Mercury

Mercury is commonly used by dentists and dental hygienists, but it can affect our lungs, brain and skin and should always be handled with care. Concerns have been raised in the past about the level of mercury contained in amalgam fillings but amalgam is still used, although there are other tooth coloured materials that are slowly becoming more popular

Mercury poisoning, can affect memory, cause trouble hearing and result in skin problems and rashes. Symptoms, as with other metals, depend on the level of exposure so you should always be cautious of this.

Metal poisoning – What are the symptoms?

The most expensive coins in the world

Posted March 15th 2017

When we think about currency, it is sometimes to surprising to realise that different coins may be made of the same, or similar, materials, and yet possess completely different values. Generally, the older and rarer a coin is, the more value it will carry, although some coins might also be considered valuable for other reasons as we explain below.

The flowing hair dollar

The flowing hair dollar is the first dollar that was ever issued by the United States government. Dating back to 1794, the coin was based on the design of the Spanish dollar and is made of an alloy that consists of mainly silver with a small amount of copper. As this coin was only in production for two years, it is understandably rare and has long been considered one of the most valuable additions to a coin collection. In 2013, one specimen was sold for $10,016,875 – the highest recorded price paid for a coin.

The double eagle

The double eagle, a coin made from 90 percent gold, is a rare sight indeed. Produced in 1933, it was a 20-dollar coin that was put into production but never released into circulation. Thanks to the Gold Reserve Act of 1934, by the time the coin was finished it was no longer considered legal tender and most of the coins were melted down. Two were given to the U.S. National Numismatic Collection and some were smuggled out, although it is thought that only 40 of the coins are still in existence. In 2002, a private owner purchased one of the coins for $7.59 million.

The Brasher Doubloon

The Brasher Doubloon is a privately minted coin that was produced by Ephraim Brasher in 1787. Both a goldsmith and a silversmith, Brasher minted the coins when he petitioned the State of New York to produce copper coins. Considered very rare, only a small number of these coins are in existence with one know to have been sold to a Wall Street firm for $7.4 million.

The Edward III Florin

The oldest coin on our list, this dates back to 1343 and was produced by King Edward III in an attempt to provide coinage suitable for use in Europe and England simultaneously. It was made of gold and at the time carried a value of six shillings. Unfortunately, the coins were considered underweight and were put out of use after only a few months with the order to melt them down in order to produce a coin called the gold noble instead. As such, there are only three copies of this coin known to exist currently. Two of them are on display in the British Museum and the last know example was sold at auction in 2006 for £460,000.

he most expensive coins in the world

The lost secret of Damascus Steel

Posted March 2nd 2017

Once popularly used in the manufacture of sword blades in the East, Damascus steel has been around for centuries. The blades it produces are distinctive looking with a mottled pattern to the metal that looks almost like pooling water. As well as their beauty however, the blades made using Damascus steel were famed for having keen edges and being extremely durable. Damascus steel is said to have been named after the city of Damascus, where such swords and blades would have been used during the 16th to 18th centuries. However, it is also possible that is takes its name from damask fabric as a comparison of the patterns between the two.

Although the original method of forging Damascus steel was lost when the material fell into disuse, modern blacksmiths have found ways of recreating it to a certain standard. Billet welding, is a popular method, and employs the technique of welding steel and iron together in layers to form a ‘billet’. This is also known as ‘pattern welding’ and the technique gives a finished product that has the same patterns as Damascus steel due to the layering of the elements. This ‘modern Damascus steel’ is often used in kitchen knives today.

Traditional cast Damascus blades would have been made from wootz, which is a type of steel originating in India. Wootz steel is thought to have been made by melting iron and steel together in a crucible. There must be plenty of carbon present as this is absorbed during the melting process. As the alloy cools slowly, the swirling patterns are formed from the carbide contents giving the unique finish the material is famous for. Although some metallurgists claim to have been able to replicate the production of wootz steel, it is unlikely it has been reproduced to the same standard as the original material. Pavel Petrovitch Anosov, a Russian metallurgist, documented four different ways to produce steel with similar patterns for example, although he passed away before being able to fully record his research and findings. Anosov was looking for a way to reproduce Bulat steel, a type of steel alloy found in Russian medieval weapons and popularly associated with Genghis Khan and the Mongols – another form of Damascus steel.

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