For many thousands of years, humanity has made good use of metals for making tools and weapons. This dates back to the Neolithic period, when some phases of societal development were defined by metal uses. The Bronze Age, Copper Age, and Iron Age are all examples of this, when earlier societies such as the Celts and others pioneered uses of certain metals that they mined. Steel was used extensively in the Middle Ages, when blacksmiths forged iron into purer steel that was lighter and stronger. Such metal was used for knight armor and swords, for example. Later, the Industrial Revolution allowed steel to be produced and used on a massive new scale, and Andrew Carnegie and his ilk pioneered this massive industry. Steel suppliers and producers today are hard at work providing hot rolled and cold rolled steel alike, and sheet piling companies may be found everywhere. But what does it mean to make cold rolled steel or hot rolled steel? And how large has this industry become?
Steel Today
The world enjoys a massive global industry of steel, with the United States, Canada, Germany, and China in particular producing a vast amount of this metal. What is more, steel is also easy to recycle and is often melted down and repurposed in order to keep up with demand. As much as 90% of the world’s steel is recycled. Steel is used largely for the construction industry, which uses nearly half of all American steel. Otherwise, this metal may be used to make cars, home appliances, and even surgical equipment (usually the stainless variety). Variations of steel such as carbon steel may also be found, and carbon steel boasts a tensile strength of 580 megalpascals (Mpa) and a yield strength of 260 Mpa. Overall, the construction industry mainly makes use of carbon steel, stainless steel, aluminum, and copper for its metal needs.
How much steel is this? Quite a bit. In 20116, for a recent example, the world produced some 1.6 billion tons of it, and in 2017, the United States alone produced nearly 82 million metric tons of steel. The United States often exports this steel to allied nations, and also receives a lot of steel from them. Canada and China in particular ship a lot of steel to the United States, the former by rail or truck and the latter by ship. The United States is Canada’s single biggest trading partner for goods of all kinds, and that certainly includes steel, whether it’s hot rolled or cold rolled steel. Steel may also be found in bars or rods as well as sheets.
How to Prepare Steel
A forge will melt down metals and improve their purity before use, and that includes steel, too. Molten steel may then be poured into molds and allowed to cool and harden into sheets, rods, bars, and more for use. What is more, these sheets of steel can be prepared in more than one way, depending on how they will be used. All steel sheets are hot rolled to begin with; that is, exposed to high temperatures while being moved through high-pressure rollers to form sheets of uniform thickness and smoothness. In some cases, that is sufficient. Hot rolled steel has slight imperfections in dimensions, but some industries such as railroad construction aren’t negatively impacted by the use of imperfectly sized steel.
By contrast, other industries, such as making cars or appliances, need steel sheets and rods with more precise dimensions, so cold rolled steel will be offered. Such steel is put through rollers at room temperature, which is certainly “cold” compared to when it is hot rolled. Such steel has the necessary precision in dimensions, and it will also have a finished surface that’s glossy and tough. Such steel is quite useful, but shippers should take care when packaging and transporting it, to ensure that it’s not damaged or warped during transit. Generally, cold rolled steel is more vulnerable to this than hot rolled steel is, so customers may require that great care is taken when the products are shipped. If the cold rolled steel arrives in good shape, it’s a tough and useful metal that can be used for nearly anything.
