mechanical engineering

Antimony
A brittle lustrous white metal used mainly as an alloying element for casting and bearing alloys and in solders.

Beryllium
A white metal similar in appearance to aluminium. Brittle at room temperature. Has many applications in the nuclear field and for electronic tubes. With copper and nickel it produces alloys with high strength and electrical conductivity. Beryllium iron has good corrosion and heat resistance.

Cadmium
A fairly expensive soft white metal like tin. Used for plating and electrical storage batteries. It has good resistance to water and saline atmospheres and is useful as plating for electrical parts since it takes solder readily.

Chromium
A steel-grey soft but brittle metal. Small traces of carbide give it extreme hardness. It is used extensively in alloys and for electroplating and is also used for electrical resistance wire and in magnet alloys.

Lead
A heavy, soft, ductile metal of low strength but with good corrosion resistance. It is used for chemical equipment, roofing, cable sheathing and radiation shielding. It is also used in alloys for solder and bearings.

Lead-tin alloys
These are used as ‘soft solders’, often with a little antimony for strength. Tinman’s solder Approximately 2 parts of tin to 1 part of lead. Used for electrical jointing and tinplate can sealing. Plumber’s solder Approximately 2 parts of lead to 1 part of tin. Used for wiping lead pipe joints. Type metal Contains about 25% tin, with lead and some antimony. Has negligible shrinkage. Bearing metal Lead based ‘white metal’ contains lead, tin, antimony and copper, etc.

Magnesium
A very light metal, only one-quarter the weight of steel and two-thirds that of aluminium, but not easily cold worked. Usually alloyed with up to 10% aluminium and often small amounts of manganese, zinc and zirconium. Used for aircraft and internal combustion engine parts, nuclear fuel cans and sand and die castings. Magnesium and its alloys corrode less in normal temperatures than does steel.

Manganese
A silvery white hard brittle metal present in most steels. It is used in manganese bronze and high nickel alloys and to improve corrosion resistance in magnesium alloys.

Nickel
Nickel has high corrosion resistance. It is used for chemical plant, coating steel plate and electroplating as a base for chromium. Nickel is used for many steel, iron and non-ferrous alloys. Nickel-base alloys Monel Used for steam turbine blades and chemical plant. Composition: 68%Ni, 3o%cu, 2%0Fe. Inconel Good at elevated temperatures, e.g. for cooker heater sheaths. Composition:  8O%Ni, 14%Cr, 6%Fe.
Nimonic A series of alloys based on 70-80%Ni, with small amounts of Ti, Co, Fe, A1 and C. Has high resistance to creep and is used for gas turbine discs and blades, and combustion chambers. Strong up to 900 “C.

Platinum
A soft ductile white metal with exceptional resistance to corrosion and chemical attack. Platinum and its alloys are widely used for electrical contacts, electrodes and resistance wire.

Silver
A ductile malleable metal with exceptional thermal and electrical conductivity. It resists most chemicals but tarnishes in a sulphurous atmosphere. It is used for electrical contacts, plating, bearing linings and as an alloying element.

Tin
A low-melting-point metal with silvery appearance and high corrosion resistance. It is used for tinplate, bearing alloys and solder.

Titanium
An expensive metal with low density, high strength and excellent corrosion resistance. It is used in the aircraft industry, generally alloyed with up to 10% aluminium with some manganese, vanadium and tin. Titanium is very heat resistant.

Tungsten
A heavy refractory steel-grey metal which can only be produced in shapes by powder metallurgy (m.p.3410 “C). It is used as an alloying element in tool and die steels and in tungsten carbide tool tips. It is also used in permanent magnets.

Zinc
Pure zinc has a melting point of only 400 “C so is good for die casting, usually with 1-2%0Cu and 4%A1 to increase strength. Used for carburettors, fuel pumps, door handles, toys, etc., and also for galvanizing sheet steel, nails and wire, and in bronze.

Aluminium

This acts as a deoxidizer to increase resistance to oxidation and scaling. It aids nitriding, restricts grain growth, and may reduce strength unless in small quantities. The range used is 0-2%.

Chromium

A range of O M % , improves wear, oxidation, scaling resistance, strength and hardenability. It also increases high-temperature strength, but with some loss of ductility. Chromium combines with carbon to form a wear-resistant microstructure. Above 12% the steel is stainless, up to 30% it is used in martensitic and ferritic stainless steel with nickel.

Cobalt

Cobalt provides air hardening and resistance to scaling. It improves the cutting properties of tool steel with 8-10%. With chromium, cobalt gives certain high alloy steels high-temperature scaling resistance.

Copper

The typical range is 0.24.5%. It has limited application for improving corrosion resistance and yield strength of low alloy steels and promotes a tenacious oxide film.

Lead

Up to 0.25% is used. It increases machineability in plain carbon steels rather than in alloy steels.

Manganese

The range used is 0.3-2%. It reduces sulphur brittleness, is pearlitic up to 2%, and a hardening agent up to 1 Yo. From 1-2% it improves strength and toughness and is non-magnetic above 5%.

Molybdenum

The range used is 0.3-5%. It is a carbide forming element which promotes grain refinement and increases high-temperature strength, creep resistance, and hardenability. Molybdenum reduces temper brittleness in nickel-chromium steels.

Nickel

The range used is 0.3-5%. It improves strength, toughness and hardenability, without affecting ductility. A high proportion of it improves corrosion resistance. For parts subject to fatigue 5% is used, and above 27% the steel is non-magnetic. Nickel romotes an austenitic structure.

Silicon

The usual range is 0.2-3%. It has little effect below 3%. At 3% it improves strength and hardenability but reduces ductility. Silicon acts as a deoxidizer.

Sulphur

Up to 0.5% sulphur forms sulphides which improve machineability but reduces ductility and weldability.

Titanium

This is a strong carbide forming element. In proportions of O.2-O.75% it is used in maraging steels to make them age-hardening and to give high strength. It stabilizes austenitic stainless steel.

Tungsten

This forms hard stable carbides and promotes grain refining with great hardness and toughness at high temperatures. It is a main alloying element in high speed tool steels. It is also used for permanent-magnet steels

This is a carbide forming element and deoxidizer used with nickel and/or chromium to increase strength. It improves hardenability and grain refinement and combines with carbon to form wear-resistant microconstituents. As a deoxidizer it is useful for casting
steels, improving strength and hardness and eliminating blowholes, etc. Vanadium is used in high-speed and pearlitic chromium steels.

Vanadium

This is a carbide forming element and deoxidizer used with nickel and/or chromium to increase strength. It improves hardenability and grain refinement and combines with carbon to form wear-resistant microconstituents. As a deoxidizer it is useful for casting
steels, improving strength and hardness and eliminating blowholes, etc. Vanadium is used in high-speed and pearlitic chromium steels.