Materials

The engineering industry is heavily dependent on steel, and it’s used in a huge range of markets from rail, oil and gas, petrochemical, automotive and machinery building. Steel is an alloy of iron that contains a small amount of carbon, much less than cast iron and usually less than 1.7%. In general the tightly controlled carbon content determines how easily the steel can be hardened by heat treatments. Other alloying elements such as nickel or chromium can also be added to steel to create a wide variety of desirable characteristics. Steel is usually separated into at least three groups. The most common groupings are: mild steels, carbon steels and alloy steels, each group having different overall attributes.

The mild steels are low in carbon content and are best suited to applications where heavy loads or stresses are not involved. These alloys are most suited to use in the manufacture of products where their easy workability and weldability make them ideal for a range of fabricated products. Carbon steels are generally stronger than mild steels. Their ability to accept hardening treatments is their greatest attribute. Alloy steels complete the range, with specific alloying elements added to make them suitable for a variety of high-strength and other applications. There are literally hundreds of specifications relating to steels. British, German and American specifications are commonly found in the UK, however, European harmonisation has added more. 


BS 970 was revised in 1970 and the EN designation was replaced by a six digit system. In this system the first three digits refer to the alloy type, the fourth digit (letter) indicates if the steel is supplied to Analysis, Mechanical property or Hardenability requirements and the fifth and sixth digits represent a value that is 100 times the (mean) carbon content.

Stainless steels most notable feature is its ability to resist corrosive attack, it is a basic alloy of steel that contains a minimum of 11% of chromium. Stainless steel is used in a wide range of applications, including the oil & gas industry for pressure vessels and in clinical environments such as hospitals, laboratories and food preparation areas.

There are four main alloy groups, known as “Austenitic”, “Ferritic”, “Martensitic” and “Duplex/Super Duplex”.

Ferritic stainless steels contain a minimum of 11% chromium and no nickel. They are magnetic.

Austenitic stainless steels contain a minimum of 18% chromium, along with a minimum of 8% nickel. They are non-magnetic. They are tougher, maintaining their strength better at high temperatures. Weldability is improved as is corrosion resistance and with the addition of less than 2% molybdenum.

Martensitic stainless steels contain a minimum of 11.5% chromium, generally with no nickel content but an addition of 0.15% – 0.4% carbon. These steels give very high strength in the hardened condition, and the abrasion and wear resistance of these alloys is well known. Duplex & Super

Duplex Stainless Steels are formed from an approximately 50/50 mixture of austenitic and ferritic and are sometimes referred to as austenitic-ferritic stainless steels. Duplex stainless steels combine the best attributes of both austenitic and ferritic stainless steels and provide high strength with good corrosion resistance, this gives them a significant advantage over 300 and 400 series stainless steels.

In its pure form, the metal possesses a high level of corrosion resistance but is low in strength. When alloyed aluminium becomes versatile and is a widely used material. The alloys used are dependent on the finished material required. Additions of copper, iron, zinc, nickel, tin, lead, magnesium and silicon are all used to improve its attributes. Increased strength, corrosion resistance, ductility, workability, weldability and machinability are all possible.

The “commercially pure” product (99.00% pure) is often used as bus-bars for electrical purposes as its conductivity in this pure state is high.

There are two main types of alloyed aluminium; wrought and cast. Wrought alloys are divided into two groups: heat-treatable and non-heat treatable. Heat-treatable alloys are strong and durable, non-heat treatable alloys have ductility, weldability and corrosion resistance.

Beryllium copper which is also known as beryllium bronze and spring copper, offers the highest strength of any copper. Applications for beryllium copper usually divide between those requiring high strength and those requiring high conductivity treatment of the finished component. Beryllium copper is also non-magnetic and non-sparking, a characteristic that makes it particularly suitable for use in explosive atmospheres.

Brass is probably the best known of the “yellow metals” and it is produced in a wide variety of forms with many different characteristics and attributes. It is a basic alloy of copper and zinc and is used in many engineering applications. Typical applications include component and equipment manufacture in a variety of industries. The name brass actually covers a wide range of alloys, but they are fundamentally a combination of copper and zinc, other elements being added to increase the strength, malleability, ductility or resistance to corrosive attack. Many components formerly made of steel have changed to brass, saving costs of machining and plating whilst not compromising on strength. Significant savings in time, machining costs and protective coatings have been made in many applications such as: hydraulic hose couplings, submersible pump components, pneumatic products, automotive components and mining equipment.

Strictly speaking, bronze is an alloy of copper and tin. However, bronze is also used to describe a wider range of copper based alloys. Phosphor bronzes have an addition of phosphor to improve strength and hardness. Superior attributes can often be attained through the addition of other elements to the basic bronze alloy. As well as phosphor, zinc and lead are the most common additions. A leaded bronze will generally have better machining characteristics than an unleaded bronze. It will, however, retain a plasticity that makes it ideal for applications such as the production of bearings. Adding zinc to bronze alloys results in an alloy commonly known as “gunmetal”. It also has good resistance to corrosion and has many applications in the marine industry.

Copper alloys are very versatile, by combining copper with other metals the resulting alloys can be made to fit almost any application. Copper has an electrical conductivity that is superior to all metals other than silver and it has a very high thermal conductivity. It is the material of choice for many applications. The softness of ‘commercially pure’ copper makes it difficult to machine however in its more highly alloyed state this is not a problem, but to retain the higher conductivity of copper, the addition of sulphur or tellurium gives a greatly increased cutting ability.

Copper-nickel alloys (often referred to as cupro-nickels) offer moderate to high strength and excellent resistance to various waters, including seawater and form a protective surface film in such conditions.

Copper Nickel Alloys provide good anti-fouling properties and weldability, possess high strength, low magnetic permeability, imperviousness to hydrogen embrittlement and no loss of impact strength down to minus 196°C.Typical applications are connectors, valve stems, mechanical seals and pump shafts.

Nickel Iron alloys are a relatively new group of materials. Each alloy has very specific, often unique, properties and the applications for these alloys are often at the cutting-edge of technology. Strength, corrosion resistance and conductivity are important factors with these alloys but it is their thermal expansion and magnetic permeability characteristics that are often the vital attributes. High-tech industries such as automotive, medical, power generation, aerospace, electronic and petro-chemical have benefited from this range of alloys.

Nickel silver alloys (sometimes called German silver) derive their name from their bright silvery appearance though they actually contain no silver at all. They are alloys of copper, nickel and zinc and they find many applications industrial applications, such as component manufacture. They are usually classified by their nickel content with higher nickel contents producing a whiter, silvery colour. Corrosion resistance increases with higher nickel content and the resulting alloys are less vulnerable to stress corrosion than some brass alloys. Strength also increases with nickel content. 
The spring properties of the alloys are good and remain so at elevated temperatures. The electrical conductivity of nickel silver is much less than that for copper. Nickel silver alloys are often used where a combination of good strength and corrosion resistance is required. They also find applications that take advantage of the material’s springing properties such as spring contacts.

Titanium is a light, strong metal with a natural resistance to marine and chlorine corrosion, it has the highest strength to weight ratio of any metal and even in its unalloyed form it is as strong as some steels but around 45% lighter. Commercially pure (CP) titanium is a term used to describe unalloyed titanium for industrial use. With such a high strength to weight ratio, Titanium has become a highly sort after material and is used in widespread applications. In the motorsport and automotive sector, the advantages of introducing titanium into car and motorcycle designs are obvious with manufacturers looking to make competitive gains whilst maintaining safety. Titanium is also widely used in the aerospace sector in airframe structures and jet engines. Oil, Gas & Petrochemical also make good use of this alloy and also the power generation industry too.

A refractory metal with a high melting point and a very high density. Tungsten can be used in a pure form but it becomes more useful as an engineering material when alloyed with small quantities of other elements to form a group of products sometimes referred to as Tungsten Heavy Metal Alloys (WHAs). Most of the major applications for tungsten alloys are based on its very high density where it is used to control or distribute weight in some way. Tungsten is up to 65% denser than lead and 130% denser than steel. Radiation shielding is a second common application area.

Since the first man-made plastic in 1856, the proliferation of new plastics with distinct properties has driven the progression of numerous and diverse applications on which the world depends today.The range of materials components are manufactured from includes a host of highly-developed materials such as PTFE, PEEK and Acetyl’s, and with the continual development in the manufacture of plastics, more and more materials are being developed which outperform the more common engineering plastics. Some products manufactured are for electrical insulation, fitted to electrical switchgear equipment, including drive links, housings, arc splitter boxes, coil formers, dropper cards, pads, pins and general bushings.

For cost effectiveness and “whole-of-life” performance, we incorporate the use of high strength and high performance materials and specialist machining. By taking an advisory role in the design stage and recommending both material and appropriate manufacturing processes, we can assist our clients to arrive at innovative, yet cost effective solutions. Our technical knowledge is matched by long-term industry experience and an open minded approach has led to the use of novel manufacturing methods in many of our projects.

Industrial laminates and composites have many advantages compared with traditional materials, such as improved machine-ability, increased performances, lower weight and a finer finish. The engineering applications are almost limitless, with components such as bearings, supports and wear pads being stronger, more effective and longer lasting. We supply local and multinational organisations in the rail, defence and chemical sectors with industrial laminate and composite components manufactured from brands such as Tufnol and Railko.

Industrial laminate is made by applying heat and pressure to layers of fabric, canvas, linen or glass cloth, impregnated with synthetic thermosetting resins. These materials are called “Thermosets.” A variety of resin types and cloth materials can be used to manufacture thermoset laminates with a range of mechanical, thermal and electrical properties.

In 1957 Railko began producing self-lubricating components made from advanced engineering composite materials of high quality, the marine and rail industries were prime users of these bearings and wear parts.