Steel comes in various shapes, forms, and sizes. It is important to understand the type of steel you have in order to match it to the right use. Steel is by far the most commonly used metal in today’s world. It has had a great significance in various stages of the history of mankind —pause and look around you — the strength and malleability of this metal is the reason for its versatility of use. It is useful in the manufacture of 316 stainless steel tube and much more. Let’s take a journey into the evolution, properties, types, and uses of steel.
What is Steel?
What differentiates steel from other iron alloys is the carbon content. For steel to attain its malleability and strength the carbon content of iron needs to be stabilized at no less than 0.2% and no more than 2%.
While steel has been part of the history of the human race since the Iron Age, it is not until the 19th century that focus has been on it. Sir Henry Bessemer is responsible for its rise to fame. His experimentation with cast iron led him to the discovery of efficient ways to extract carbon for it leaving close to 2% of it. This led to the genesis of the various practices used to derive steel from iron on a commercial scale to produce different grades like 316 stainless steel tube.
There exist two methods in which steel is derived from iron. The first and most popular is known as the basic oxygen method or basic oxygen steel-making (BOS). This entails the blasting of oxygen into large chambers holding molten iron. Scrap steel can also be molten and subjected to this process. The other method of obtaining steel is through electric arc furnaces (EAF). This method came to effect in the 20th century and is slowly gaining popularity over the former.
Types of Steel and Their Uses
Yes, this metal that is essentially comprised of two key elements does come in various types and qualities (also known as grades). In fact, there exist over 3,500 grades of this metal. The differences in the grades come from the differences in physical, environmental and chemical properties. Another contributing factor to these differences is the impurity levels found in each grade as well as any other alloying elements. The grade within which steel is found is also determined by its elasticity, density, strength, thermal conductivity, and hardness. These differences also determine the application of steel. To keep from creating a sense of chaos in the construction world, steel is generally divided into four main categories.
First, we have carbon steel. This type of steel can further be subdivided into high carbon, ultra-high, medium and low carbon steel. They get their name from the elements used in the alloy, carbon, and iron. The level of carbon in the steel determines its strength as well as its fragility.
Steel in the ultra-high carbon category may also be referred to as cast iron. This steel is ideal for cooking pots. Similar to steel in the high carbon category, cast iron is known for its hardness as well as its brittleness. High carbon steel is mainly used for the manufacture of wires.
Low and medium carbon steels are more malleable than their high and ultra-high counterparts. The former, also known as wrought iron, has ore decorative applications. It can be used in the fabrication of lamp posts, fences, seats and other artistic products. The latter is more common in the construction industry, more so for the erection of large structures.
Next, we have alloy steel varieties. These derive their name from the fact that they possess traces of other metals such as silicon, chromium, nickel, aluminum, and manganese. One such example is stainless steel. This type of steel is an alloy of iron, nickel, and chromium. Alloys of manganese are known for their hardness as well as strength. Aluminum is useful when making alloy steels as it helps give a visual uniformity. Chromium in stainless steel helps to make the steel corrosion-resistant.
Stainless steel can further be subdivided into austenitic, ferritic and martensitic steels. The difference here lies in the amounts of chromium found in each alloy. High chromium levels can be found in austenitic steels. This makes them particularly corrosion resistant as well as non-magnetic. It is these properties that make them useful for the fabrication of stainless steel piping as well as in the food processing industry. Ferritic steel has 15% chromium while martensitic steels contain chromium, nickel, and carbon in moderate portions. These are often useful in the fabrication of cutting tools. Lastly we have tool steel. These are known for their durability and heat resistance. They are alloys of metals such as cobalt, vanadium, tungsten as well as molybdenum.