Metal ranks high among the construction materials that humanity uses, and in fact, several prehistoric eras were named after the most commonly used metals of the time. For example, the Iron Age or the Bronze Age of Europe. Starting in the 1800s, meanwhile, the Industrial Revolution greatly boosted how much steel could be produced, and mass-produced steel was used to make everything from railroad tracks to steam ship and skyscraper I-beams. This is still true today, though metals such as aluminum and a wide variety of alloys are also useful. For example, 17-7 stainless steel can be used to make statues, and thin steel sheets can be bought wholesale for making electronic goods. Thin sheet metal can be hot rolled or cold rolled in a factory, and copper and brass alloys can offer properties that even the likes of 17-7 stainless steel cannot.
Steel and Aluminum
Strictly speaking, steel dates back at least to the Middle Ages, when blacksmiths created it out of iron to make knight swords and shields. But that steel was made in limited quantities, while the Industrial Revolution introduced steel mills in Europe and North America that could produce incredible amounts of this metal. Today, steel is a widely exported and imported material, and the United States imports a lot of steel from Canada, China, and Germany. This is a big industry in the United States, with 138,900 sheet metal workers at work in 2016. The U.S. Bureau of Labor Statistics predicted that the metal fabrication industry may grow 9% from the year 2016 to 2026, adding 12,000 new jobs making 17-7 stainless steel and the like.
Today, steel such as 17-7 stainless steel and more can be used to make statues, and stainless steel can also be used to make surgical gear and cutlery, since it is corrosion and rust resistant (hence the name). Steel is also used to make I-beams and railroad tracks like it was in the 1800s, not to mention car parts and more. Steel is lighter and stronger than iron, and steel I-beams were what made skyscraper construction possible. How to make steel? Once iron is melted down into steel, it will be hot rolled through a series of rollers at high temperature to produce sheets of it. Hot rolled steel has imprecise dimensions, but that is acceptable for uses such as making railroad tracks and I-beams. Meanwhile, that steel can be passed through the rollers again but at room temperature this time, and the result is cold rolled steel. Cold rolled steel has precise dimensions and a protective coat, making it useful for making manufactured items like car parts.
Aluminum plays a role, too. It is even lighter than steel, and more and more vehicles are being made with aluminum to lower their weight and thus make them more fuel efficient now in the 21st century. Aluminum is also widely used to make electrical goods and appliances, and aluminum is also used to make the rims of car wheels.
It is clear that steel and aluminum are quite useful in many sectors, but not even these flexible metals can do absolutely everything. Some job environments are too extreme for them, such as extremes of heat or cold, pressure, or corrosive materials. Steel would suffer, but not alloys designed for the job.
An alloy is a composite metal made up of two or more ingredient metals in certain ratios and percentages, creating a metal with desired properties. Metals such as iron and steel, copper, brass, aluminum, titanium, nickel, and more can be used to make alloys. For example, copper alloys are often used to make undersea pipes, which are exposed to salt water both on the outside and inside. This would corrode steel pipes, but not these alloy ones, which are geared to handle that environment. The same is true of tanks, pipes, and valves inside a chemical plant. Alloys can also be used to make jet engine or train engine parts, and endure extremes of temperature and pressure for hours on end. Alloys are also ideal for making metal bellows, which are flexible metal tubes that can expand and contract without bursting while carrying heated gases or liquids.