Steel Structure Workshop Construction – Characteristics of Several Common Steel Grades Used in Jiangsu Province
# English Translation As we mentioned earlier, steel structures in Jiangsu, China are composed of various members connected by welding, riveting or bolting. What types of steel are commonly used in Jiangsu steel structure buildings, and what are the differences in steel selection and purchasing? We all know that different steel grades have greatly different properties. Steel structure members should generally be made of various section steels. The base metals used are mainly carbon structural steels and low-alloy high-strength structural steels. Section steels are available in hot-rolled and cold-rolled types. Steel plates also include hot-rolled (thickness 0.35–200 mm) and cold-rolled (thickness 0.2–5 mm) types. ### (1) Hot-rolled section steel Hot-rolled section steel includes angles, I-beams, channels, T-sections, Z-sections, etc. Hot-rolled section steel for construction in China mainly uses carbon structural steel **Q235-A** (carbon content 0.14–0.22%). It has moderate strength, good plasticity and weldability, and low cost, making it suitable for construction engineering. Two low-alloy steels are recommended in the steel structure design code: **Q345 (16Mn)** and **Q390 (15MnV)**, which are used in steel structures with long spans and subjected to dynamic loads. ### (2) Cold-formed thin-walled section steel These are usually cold-bent or stamped from 2–6 mm thick steel plates, including open thin-walled sections such as angles and channels, and hollow thin-walled sections such as squares and rectangles. They are mainly used for light steel structures, with the same marking method as hot-rolled section steel. ### (3) Steel plates and profiled steel sheets Flat steel products rolled with smooth rolls are called steel plates when supplied as flat sheets, and steel strips when supplied in coils. According to rolling temperature, they are divided into hot-rolled and cold-rolled: - Hot-rolled steel plates are classified into heavy plates (thickness > 4 mm) and thin plates (thickness 0.35–4 mm). - Cold-rolled steel plates are only thin plates (thickness 0.2–4 mm). Steel plates and strips for construction are mainly carbon structural steel. Some heavy structures, long-span bridges, high-pressure vessels, etc., also use low-alloy steel plates. Generally, medium-thick plates can be used for welded structures; thin plates can be used for envelope structures such as roofs and walls, or as raw materials for coated steel plates. Steel plates can also be bent into section steel. Thin steel plates are cold-pressed or cold-rolled into corrugated, hyperbolic, V-shaped and other profiles, known as **profiled steel sheets**. Color-coated steel sheets (organic coated thin steel sheets), galvanized thin steel sheets, anti-corrosion thin steel sheets, etc., can be used to produce profiled steel sheets. Their features include light unit weight, high strength, good seismic performance, fast construction and attractive appearance. They are mainly used for envelope structures, floor slabs, roofs, etc. Of course, in previous articles we have covered many tips and precautions for selecting steel for steel structures. Friends in need can follow our website *Jiangsu Steel Structure* for more professional knowledge about steel structures.