Hot rolled hexagon steel and octagonal steel (GB 705-89)
Hot rolled hexagon steel and octagonal steel, commonly known as hexagonal steel and octagonal steel respectively, are materials used in manufacturing large equipment, bridges and other structures. They are specified and regulated by GB 705-89.
Hexagonal steel and octagonal steel are rolled in hot-rolling mills, in which steel is heated to temperatures higher than the re-crystallization threshold, 900-1300℃, which alters the structure of the steel and increases its strength. Heating causes particles and fibers to align in the rolling direction, resulting in a linear and clear grain structure.
Hexagonal steel and octagonal steel have many similarities and differences. They have the same processing technology, rolling, annealing and so on; Moreover, their chemical element percentage and microstructure are generally similar. The main difference between them lies in their cross-sectional shape. The cross-sectional shape of hexagonal steel is symmetric, while the cross-sectional shape of octagonal steel is not. The other major difference lies in their mechanical properties. Hexagonal steel has higher tensile strength than octagonal steel, while Octagonal steel has more yield strength.
The application of hexagonal steel and octagonal steel depends on their respective strength and deformation characteristics. Hexagonal steel is widely used in construction and other related industries, such as bridge structures because of its high tensile strength. On the other hand, octagonal steel is widely used in equipment, as it can resist greater compressive and torsional loads.
The use of hexagonal steel and octagonal steel is governed by GB 705-89, which is issued by the State Standardization Administration. The standard determines the chemical composition, mechanical properties, allowable deviations and packaging requirements for these two steel materials. This standard also applies to the corresponding welding materials. Lighting up the source for welding should also meet GB 705-89 standards.
In conclusion, overall, hot rolled hexagon steel and octagonal steel are suitable for making parts for construction and engineering projects. Their different shapes and strengths mean they can be used in different ways according to the specific requirements of the project. It is important to ensure that they are manufactured and welding materials are used according to GB 705-89. This standard ensures that the integrity and safety of the parts manufactured using hexagonal steel and octagonal steel meet the highest requirements.
