Heat Treatment

Steel Heat Treatment

In the modern era, there seems to be an unrelenting need for stronger and better materials to make ever more advanced devices and structures. From LCD screens to Eco-friendly light bulbs to state of the art bridges, new challenges in human endeavors call for newer, ever more unusual materials. Some materials, however, remain as heavily in demand as they’ve ever been, as much because they get the job done as well as they ever have as inventors have found new uses for them. It is into this mix of supply and demand and invention that many technologies find themselves being pushed into new places.

Steel is one such material that remains as highly in demand has it has since its invention centuries ago. While steel has certainly become common, its durability and flexibility as a material has not. Where once a steel weapon was an incredibly valuable treasure, now steel is seemingly everywhere, yet demand for the material has not abated in the past few centuries. It’s not hard to see why; strong, easily shaped and relatively cheap for what it does, steel may have become a practically mundane material, but it remains as impressive as it was when it was invented.

The process of making steel has likewise changed, though the principles remain roughly the same as they always have been. The process requires that iron be combined with another substances through heat treatment process of steel. The essence of the process is combining iron and one or more other substances in a specialized environment called a crucible that is heated to a temperature hot enough to melt iron and the other substances past their melting point until they reach a state where the materials can merge together chemically, creating what is referred to an an alloy of the different materials.

Sometimes the crucible is a smaller forge, that merges different metals together in a mostly solid form with the assistance of a blacksmith’s hammer and strength. Industrial steel, however, is generally reduced to liquid metal in massive foundries and poured into amazingly solid molds to produce steel in the shapes required for industry, be it steel girders or firearms. When the metal comes out of the crucible, whether a backyard forge or industrial foundry, it is incredibly hot and always needs time to cool properly. Quenching steel, or any metal, generally requires dipping it into a liquid that is cooler than the crucible, though the exact liquid can have an impact on the chemical properties of the final product; quenching steel solely in water often leads to brittle material, while quenching it in motor oil makes it nigh-indestructible at the cost of making it nearly impossible to work with.

Combining metals and other materials into an alloy is a variable process. The exactly other materials combined with the iron going into the crucible will definitely have an impact on the final product. Alloys of iron and carbon, often times with small amounts of molydenum, manganese, chromium or nickel, are the carbon steel alloys and make up for around 90 percent of steel produced worldwide. Alloy steels tend to use a wider array of materials.

For instance, for steel to be considered stainless steel, it must contain an absolute minimum of 11 percent chromium, which usually gets mixed with nickel, to create a steel that can resist corrosion. Tool steels often contain sizable amounts of tungsten and cobalt to make them as hard as possible for use in tools such as axes and drills. Heat treatment is the very back bone of the production of steel, without which there is no steel. It is not the safest process, but it is vitally necessary for the modern world.