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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

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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2016 – The UK steel industry and Tata Steel

Posted January 25th 2017

2016 was a turbulent year for the UK steel industry. Featuring in headlines such as, ‘Britain’s steel industry: What’s going wrong?’, and ‘Steel crisis far from over…’, it’s safe to say that the industry has been sorely hit over the last 12 months.

The privately owned Tata Steel has been instrumental in some of the changes we have seen. In January 2016, Tata Steel announced their intentions to cut 1060 jobs in the UK with 750 of those at Port Talbot, the UK’s largest steelworks and one of only two sites in the UK to make steel in a blast furnace. This paved the way for protests in Brussels and London as steelworkers expressed their outrage and worries about the direction taken by Tata Steel. Unions demanded that the EU take action to prevent the importation of cheap, Chinese steel flooding the market and ultimately costing jobs.

Despite a survival plan being drawn up at Port Talbot, the company board initially rejected this and shocked many by announcing their intention to sell their UK steel business entirely. The UK and Welsh governments both offered financial support for a management buyout of the UK plants, however, the company’s pension scheme deterred potential buyers.

In December a deal was finally agreed to keep the Port Talbot plant open, with proposed changes to the pension scheme that would result in a 10% cut to members benefits. Although union leaders have backed the plan, a ballot of steel workers will ultimately decide whether to accept the changes on 30 January 2017. If the deal goes ahead, Tata will commit to a 10 year and £1bn investment plan at Port Talbot as well as keeping the blast furnaces open for a at least the next five years. Whilst this is good new for the UK steel industry, it remains to be seen whether the workers are willing to accept the price.

TATA

Additive Manufacturing – What is it?

Posted January 17th 2017

Additive Manufacturing (AM), also known as 3D printing, rapid prototyping or freeform fabrication is a process in which layers of material are used to form three dimensional objects under computer control; opposed to Subtractive Manufacturing such as machining.

The use of AM with metal powders is a new and expanding industry, with the ability to now produce complex metal parts rather than just prototypes as before. This is enabling a design revolution in various sectors such as automotive, medical, tooling and energy among others. There are currently a wide range of metal powders being used in AM such as, Steels e.g. 316L, Nickel & Cobalt super alloys, titanium alloys & aluminium alloys. Many more powders are being developed including; copper alloys, magnesium alloys, precious metals and Tungsten alloys.

Using AM over more traditional production methods has the following benefits:

  • Reduction in waste (Net shape process) – In standard aircraft manufacture up to 90% of material can be cut away
  • Increased design freedom
  • Possibility of lightweight structures e.g. lattice designs
  • Potential for several parts to be constructed as one
  • Reduced assembly operations e.g. welding
  • Shorter production cycles
  • No other tools needed e.g. molds

However this new technology also has several limitations:

  • Only suitable for smaller parts up to 2-3kg
  • Not yet suitable for mass production; the current capability for smaller parts is around 25,000 parts per year
  • Design limitations – removable support structures can be required if an overhang is less than a 45° angle
  • Material type – it is not yet possible to use non-wieldable metals in AM
  • Porosity – can be some residual internal porosity
  • Mechanical properties – the parts tend to be inferior to those which are wrought

Additive Manufacturing – What is it?

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