Steel is a vital component in the economy. It is widely used in manufacturing domestic products, automotive industry, construction industry, and manufacture of medical equipment. Steel is not made the same. Each type of steel has unique properties making it more suited for particular tasks. Some of the features that distinguish the types of steel include weight, sturdiness, ductility, and versatility.
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Steel grade
There are comprehensive grading systems to categorize steel according to its applications and properties. The systems have standard guidelines across industries to ensure material integrity. Steel grading systems include:
The American Society for Testing and Materials (ASTM) is the alphanumeric classification denoting the overall categorization and particular attributes of steel.
The Society of Automotive Engineers (SAE) grade is a four-digit numerical classification highlighting the type and carbon content of steel including its alloying elements.
Types of steel
Stainless Steel
Carbon content is the benchmark to define the types of steel. Stainless steel has a minimum chromium content of 10.5 percent. It contains iron and carbon with additional chromium as a key component that gives it unique properties. The most significant feature of stainless steel is protection from oxidization. This means that steel doesn’t degrade over time just like other metals because of its sheen provided by chromium. So, stainless steel is the choice for medical equipment, cookware, and construction bars and tubes.
Stainless steel has subtypes each with unique properties and market price. Austenitic stainless steel alloy is the most common for its resistance to oxidation, non-magnetic, and unique appeal. This is further divided into alloys including austenitic, martensitic, and ferritic. You can buy 321 stainless steel tube for enhanced corrosion resistance for various applications such as exhaust manifolds and aircraft collector rings. Other grades of austenitic stainless steel alloy include:
- Grade 304
- Grade 309
- Grade 316
- Grade 302
Carbon Steel
This is technically a metal alloy containing iron and carbon. Carbon steel is defined in the manufacturing industry in various ways including steel with 2 percent carbon content. Alternatively, carbon steel is steel without any standard amount of elements to become alloy steel. Carbon steel is sometimes known as steel with less than 0.4 percent copper or steel with particular copper or magnesium content. Keep in mind that the various definitions of carbon steel vary by industry.
Generally, steel is categorized into low, medium, and high. Low carbon steel has about 0.30 percent carbon and the most common on the market for being relatively cheap. This type of steel is easy to form for applications requiring tensile strength like structural beams. Medium carbon steel has about 0.31 to 0.60 percent carbon and about 0.31 to 1.60 percent magnesium. High carbon steel has about 0.61 to 1.50 percent carbon and about 0.31 to 0.90 percent magnesium. This type of steel is the hardest and toughest for applications like bars, railways, and plates.
Alloy Steels
The third type of steel is alloy steel. It is the most diverse and widest range. Alloy steel is a combination of various alloy elements that give it unique properties. There are various steel alloys including chromium, nickel, cobalt, and tungsten. Creating steel from the properties of the various alloys is possible.
Tooling steels
Last is tooling steel for applications such as drilling. The most common type of tooling steel includes vanadium, cobalt, and tungsten. Tooling steel is durable, strong, and heat resistant. It is available in various grades including hot-working, oil-hardening, air hardening, and shock-resistant type.
How to choose the right steel for your needs
Machinability properties
The ease of modifying steel is the machinability property. Keep in mind that manufacturers use various processes to make steel products including cutting, drilling, or hearing. Special equipment is used to determine the steel machinability including the time a tool takes to cut through the steel. This allows selecting the ideal steel grade to match your requirements.
Tensile strength
The quality of resistance of material on exposure to tension matters when selecting steel for your needs. Opt for steel that withstands damage for a long time. The tensile strength of steel is determined using test rigs and an extensometer. This quantifies the amount of peak force the sample steel takes before breaking.
Heat treatment capability
All types of steel have different capabilities to withstand heat treatment. So, you have to keep this in mind when selecting steel for your requirements. Stainless steel can’t withstand heat treatment anymore to enhance its strength but requires cold-working.
Operating environment
Choosing the right steel for your requirement depends on your working environment. The various elements in the environment might affect the performance quality of the steel. Frequency of impact, high temperatures, and pH level are important factors you should consider. Facilities with high temperatures are prone to emissions from machines that affect the functionality and utility of steel material over time.
Steel is everywhere in our daily life. When selecting steel for your application, understanding the types available is very important. Equally important is to know how to pick the right steel for your requirements.
