A Beginner’s Guide to Steel: The Three Major Types You Need to Know (Shapes, Sheets, Pipes)
As an indispensable basic material in modern society, steel comes in a wide variety and is used in many applications. According to statistics, about 60% of the steel produced globally each year is used for construction and infrastructure projects.
Whether it’s towering skyscrapers, massive bridges spanning rivers, or the cars and home appliances we use in our daily lives, all rely on steel as a fundamental material.
Steel can be divided into three main categories according to its shape and use: structural steel, steel plates, and steel pipes. Each of these three types of steel has its own characteristics, together forming the backbone of modern industry.
01 steel
Structural steel is steel that has been plastically processed into specific cross-sectional shapes and sizes, and can be considered the ‘backbone’ of construction and engineering. Depending on the production process, structural steel can be classified into hot-rolled steel, cold-bent steel, welded steel, and others.
Hot-rolled sections are steel profiles rolled above the metal’s recrystallization temperature, featuring large production scale, high efficiency, and a wide variety of types, but they develop residual stresses after cooling. Cold-bent sections, on the other hand, are made from steel plates or strips and bent into shape at room temperature, characterized by economically reasonable cross-sections and high strength.
Common Types of Steel and Their Applications
I-beam, named for its I-shaped cross-section, is mainly divided into standard I-beams and light I-beams. The web thickness of standard I-beams is uniform, and the inner sides of the flanges are beveled. Its specifications are expressed in centimeters of web height. I-beams are widely used in various building structures, bridges, and vehicle manufacturing.
H-beam steel is an economical and efficient profile with a more optimized cross-sectional area distribution and a more reasonable strength-to-weight ratio. It is named for its cross-section, which resembles the letter ‘H’. Compared with I-beam steel, the flanges of H-beam steel are wider and the inner and outer surfaces are parallel, making it easier for machining and structural connections.
H-beam steel can be divided into three types: wide-flange, medium-flange, and narrow-flange. It is widely used in beams and columns in industrial and civil buildings, as well as in supports and foundation piles of industrial structures.
Channel steel is a long steel bar with a cross-section in the shape of a groove. Its specifications are expressed by the height of the web in centimeters, for example, a No. 5 Channel steel has a web height of 5 cm. Channel steel is divided into ordinary Channel steel and light Channel steel, and it is commonly used in building structures, vehicle manufacturing, and other industrial structures.
Angle steel, commonly known as angle iron, is a long steel bar with two sides perpendicular to each other, forming an angle. It comes in equal-angle and unequal-angle types. Equal-angle steel has sides of equal width, and its specifications are expressed in millimeters as width × width × thickness. It is widely used in various building and engineering structures, such as beams, bridges, and transmission towers.
02 steel plate
Steel plates are rectangular sheet steel with a large width-to-thickness ratio. They can be classified by thickness into thin plates, medium-thick plates, and extra-thick plates. Generally, plates with a thickness of 0.2-4 millimeters are called thin plates, those with 4-60 millimeters are called medium-thick plates, and those over 60 millimeters are called extra-thick plates.
The production processes of steel plates mainly include hot rolling and cold rolling. Hot-rolled plates are rolled above the recrystallization temperature, which offers the advantages of good toughness and easy processing, but their dimensional accuracy is slightly lower. Cold-rolled plates are rolled below the recrystallization temperature, providing good surface quality and precise dimensions, but their production cost is higher.
Common Types of Steel Plates and Their Applications
Hot-rolled steel plates are produced through high-temperature rolling, with a dark gray surface. They are characterized by high strength, good toughness, and ease of processing and welding. Common hot-rolled steel plates include ordinary carbon structural steel and low-alloy high-strength steel.
It is widely used in the manufacturing fields of ships, automobiles, bridges, construction machinery, pressure vessels, and more. In construction, hot-rolled steel plates are often used to make load-bearing components such as beams and columns of steel-structured houses and crane beams in industrial plants.
Cold-rolled steel sheets have a smooth and flat surface, precise dimensions, and are characterized by high strength and excellent processing performance. Cold-rolled sheets are widely used in fields that require high surface quality, such as automobile manufacturing, home appliances, and instrument casings.In furniture manufacturing, cold-rolled steel sheets are often used to make file cabinets, office desks, and other modern office furniture.
Galvanized steel sheet is a steel sheet coated with a layer of zinc on its surface, mainly for the purpose of rust prevention. According to the production process, it can be divided into hot-dip galvanized sheet and electro-galvanized sheet.
Hot-dip galvanized sheets have a thicker zinc layer and good corrosion resistance; electro-galvanized sheets have a uniform zinc layer and good surface quality. Galvanized sheets are widely used in building roofs, appliance casings, ventilation ducts, and other applications.
03 steel pipe
Steel pipes are long steel materials with a hollow cross-section and no seams around the perimeter, widely used as pipelines for transporting fluids. According to the manufacturing process, steel pipes can be divided into two main types: seamless steel pipes and welded steel pipes.
Seamless steel pipes are made by perforating a whole round steel bar and have no welds, providing higher strength under high pressure. Welded steel pipes are made by rolling steel plates or steel strips into shape and welding them, which offers high production efficiency and lower cost.
Main Types of Steel Pipes and Their Characteristics
Seamless steel pipe is made by piercing a steel ingot or solid tube billet to form a rough pipe, which is then processed by hot rolling, cold rolling, or cold drawing. Because it has no weld seam, it features high pressure resistance and uniform mechanical properties.
Widely used in high-pressure boiler pipes, petroleum geological drilling pipes, petrochemical pipes, as well as high-precision structural pipes for automobiles and aviation. In the energy industry, seamless steel pipes are key materials for oilfield drilling and oil and gas transportation.
Welded steel pipes can be divided into straight seam welded pipes and spiral welded pipes according to the type of weld seam. The production process of straight seam welded pipes is simple, with high production efficiency and low cost, but their pressure resistance is relatively low.
Spirally welded pipes generally have higher strength than straight-seam welded pipes. They can be produced with larger diameters using narrower billets, and pipes with different diameters can also be made from billets of the same width.
Stainless steel pipe is a type of steel pipe with corrosion resistance. According to the manufacturing process, it is divided into stainless steel seamless pipe and stainless steel welded pipe. Stainless steel pipes are characterized by corrosion resistance, high temperature resistance, high strength, and high cleanliness.
It is widely used in food processing, medical devices, chemical equipment, household appliances, and other fields. In architectural decoration, stainless steel pipes are often used to make handrails, railings, and other components that require both structural strength and aesthetic appeal.
Conclusion
With the advancement of technology and the increasing emphasis on environmental protection, steel is developing in the direction of high performance, low cost, and eco-friendliness. New types of steel, such as refractory steel, high-strength steel, and weathering steel, are constantly emerging, providing more options for the construction and manufacturing industries.
No matter how material science develops in the future, for a considerable period of time, shaped steel, steel plates, and steel pipes will remain indispensable foundations for building our modern civilization.