Aerospace steel 

Steel is an alloy of pure iron and carbon (except in stainless steels), with a wide range of other materials. In addition to carbon, steels may contain chromium, nickel and titanium. Steels can be produced with a wide range of properties, ranging from extremely hard and brittle to very soft and ductile (able to be bent and stretched). Many steels are very prone to corrosion, including those which have the highest strength.

By excluding carbon from the composition, it is possible to produce stainless steel, which does not corrode easily. However, even stainless steels should not be considered totally corrosion-resistant; they may corrode in certain circumstances. Other steels may be protected by plating with another metal, such as zinc or cadmium, although cadmium is used less in modern applications because it is toxic.

All steels share one property - they are dense. Steel finds most usage where its strength can be used to best advantage, for instance where space is limited, or where its hardness and toughness are needed. The most common use is in bolts, shafts and bearing surfaces. It has one more advantage - it performs much better at higher temperature than many other materials.

Advantages of steel over other aerospace metals

Aerospace steel is relatively cheap and readily available. It has consistent strength.

When alloyed steel offers a wide range of properties available depending on the suitability of the choice of alloy and heat treatment. High strength is useful where space is limited. Some stainless steels are highly resistant to corrosion and high-tensile steels have high SWR. Its hard surface is resistant to wear and suitable for use at higher temperatures than light alloys. Most steels are easily joined by welding, offer very good electrical and magnetic screening and show good fatigue limit.

Disadvantages of aerospace steel include poor strength-to-weight ratio, except for high tensile alloys. Steel is dense, so care must be taken not to use very thin sections, or buckling may result.

Most steels are, of course, very prone to corrosion.