A profile is an object with a certain geometric shape made of iron, steel, and materials with certain strength and toughness through processes such as rolling, extrusion, and casting. 

Steel sections are divided into ordinary steel sections and high-quality steel sections. Ordinary section steel is divided into large section steel, medium section steel, and small section steel according to the current metal product catalog. 

Ordinary steel can be divided into I-beams, channel steels, angle steels, round steels, etc. according to their cross-sectional shape. 

1. Large section steel: I-beams, channel steels, angle steels, and flat steels in large section steel are all hot-rolled. Round steels, square steels, and hexagonal steels are not only hot-rolled, but also forged and cold drawn. I-beams, channel steels, and angle steels are widely used in industrial buildings and metal structures, such as factories, bridges, ships, agricultural machinery and vehicle manufacturing, transmission towers, transportation machinery, and often used in conjunction with them. Flat steel is mainly used for bridges, building frames, fences, power transmission, ships, vehicles, etc. Round steel and square steel are used as various mechanical parts, agricultural machinery accessories, tools, etc. 

2. Medium sized section steel: The use of medium sized section steel for work, groove, angle, circle, and flat steel is similar to that of large-sized section steel. 

3. Small section steel: Small section steel is processed and used similarly to large section steel in terms of angles, circles, squares, and flat steel. Small diameter circles are commonly used as building steel bars.