Carbon structural steel Q255A

Carbon structural steel Q255A

Carbon structural steel Q255A is a carbon structural steel with carbon content of 0.25%. Compared with Q235A, it has slightly higher strength, so it is often used for manufacturing products requiring higher strength. Usually, after heat treatment or welding, the flow curve of Q255A steel will be s-shaped and very narrow.

The physical properties of Q255A are described in Table 1. Q255A is a plain carbon structural steel, so its strength and hardness increase with the increase of carbon content, but its plasticity and toughness decrease. The density of Q255A steel is 7.7-7.88g/cm3. The melting point of the steel is 1480℃.

Q255A is a kind of medium carbon low alloy steel. According to ASTM, the steel is a Carbon Structural Steel. This grade is composed of Iron, Carbon, Manganese, Chromium, Nickel, and Silicon elements, with a maximum carbon content of 0.25%. Q255A has excellent weldability, plasticity and toughness. Its chemical components are shown in Table 2.

Q255A has good machinability and can be hardened by heating and then quenching. The mechanical properties of Q255A are determined by the tensile strength and yield strength. Its tensile strength can reach 460-570MPa, and its yield strength can reach 255MPa. The results of room temperature impact test are shown in table 3.

Slightly higher strength makes Q255A widely used in many fields, such as vehicles, ships, construction and manufacturing, bridges, pressure vessels, mining machinery, transportation equipment and other fields.

Q255A is generally used in medium and heavy load components or parts which need medium strength but no special strict requirements on plasticity. Most of these parts or components are welded structures, and their manufacture is convenient and low cost.

In conclusion, Q255A has higher strength than Q235A, and its physical and mechanical properties are relatively stable. It is widely used in various fields requiring medium strength. The structure of Q255A is s-shaped and very narrow after heat treatment or welding.

Carbon Structural Steel Q255A

Carbon structural steel Q255A is a kind of carbon structural steel with low yield strength, good welding and plasticity and general carbon steel. The production process of carbon structural steel Q255A is divided into smelting, rolling and heat treatment, which is mainly produced through smelting, rolling and heat treatment.

Q255A has a certain amount of alloy elements added, which not only enhances the strength, plasticity, wear resistance and corrosion resistance of the material, but also reduces the brittle transition temperature of the material, making it easier to weld and plastic. The strength of Q255A steel is greater than that of ordinary carbon steel, and its hardness increases with the increase of carbon content, but its plasticity and toughness reduce.

Q255A is mainly used to manufacture automobile, bridge, shipbuilding and other smelting industries, such as high-strength bolts, nuts, rivets. It is used to manufacture beams (H-shaped steel, I-shaped steel, channel steel). L-shaped steel, Angle steel, etc.), light components (rails, flat bars, plates and other building materials components), rolling and other metal products. Q255A steel has better performance than ordinary Q235 steel.

In order to ensure the use performance of Q255A material, various special tests and inspections should be strictly carried out during the usage process, such as ultrasonic inspection, x-ray inspection and other non-destructive testing, as well as impact testing, universal testing machine and other mechanical tests. In addition, it is necessary to reduce the surface crack and fatigue cracks of the material to ensure the permanent integrity of the structure.