Even though there are more than 3500 different grades of steel, we are not going to talk about all of them here. Of course, all of them differ and feature unique chemical, physical and environmental properties, but in essence, steel is a combination of carbon and iron.
Even though the amount of carbon and other impurities will determine the steel grade, you should have in mind that it could range between 0.1% and 1.5%.
It can contain other elements too such as phosphorus, manganese, and sulfur, and even though manganese will provide beneficial effects, sulfur and phosphorus can affect its durability and strength.
For instance, it is standard material when it comes to steel water tanks because it can withstand harsh conditions without any additional problems. But still, we can differentiate types of steel based on properties that are required for their application.
Steel can be categorized into four groups based on chemical composition:
Carbon steels tend to contain trace amounts of other elements, and they mostly feature 90% of total steel production in the world. We can also differentiate three types of carbon steel based on the carbon content inside:
- Low Carbon Steel – It can contain up to 0.3% carbon, and we also know it as plain-carbon steel. It is the most common form of steel due to its low price and the flexibility that will provide you the possibility to use it for a wide array of applications. You should have in mind that this particular type features lowest yield failure percentage, so it is an excellent choice for any application due to its high density.
- Medium Carbon Steel – The carbon content can vary between 0.3% and 0.6%. It features additional alloying ingredients with the idea to increase its strength as well as wear properties. These ingredients include silicon, molybdenum, chromium, vanadium, nickel, and manganese. At the same time, it features a minimal amount of impurities such as sulfur and phosphorus.
- High Carbon Steel – They contain more than 0.6% of carbon. When carbon steels undergo exceptionally high heat treatment, the carbon content increases gradually. However, it features maximal amount of other elements as well as impurities that affect its overall quality. Due to high levels of sulfur, it is also called red short steel. Manganese will improve its hardenability, and it should have up to 1.65% manganese
Alloy steels tend to feature alloying elements that we’ve mentioned above such as chromium, copper, titanium, nickel, silicon, manganese and aluminum, and since they can manipulate the properties of steel such as corrosion resistance, hardenability, ductility, strength, and formability, it is not as popular as carbon steel.
It is a common choice for pipelines, transformers, auto parts, electric motors and power generators among other things.
You have probably heard everywhere about stainless steel which is the part of numerous parts in both consumeristic and industrial market. It features between 10% and 20% chromium, which is the primary alloying element because it features high corrosion resistance.
Visit this link: https://en.wikipedia.org/wiki/Stainless_steel to learn more on stainless steel and its properties.
If you combine chromium with steel, it will become a hundred times more resistant to corrosion when compared with other types. We can differentiate three groups based on their structure and chemical perspective:
- Austenitic– This particular type is completely non-heat treatable and, and in most cases, it features eight percent of nickel, 0.8% carbon and 18% chromium. It creates the most significant portion of the worldwide steel market, and it is mostly used for food processing equipment, piping and kitchen utensils.
- Ferritic – On the other hand, this particular type of steel features traces of nickel, less than 0.1% carbon and between 12% and 17% chromium, along with other alloying elements such as titanium, aluminum, and molybdenum. It is highly magnetic, but you won’t be able to harden it with heat treatment, but with cold working, which means that production is different and that is the main reason for its expensive price tag.
- Martensitic – Martensitic steel features less than 0.4% nickel, 1.2% carbon and between 11% and 17% chromium. It features both heat treatable and magnetic properties, so it is used for cutting tools, knives as well as for surgical and dental equipment.