What are the characteristics of medium and thick plate, ASTM A709 structural steel sheet? First, the performance of shock resistance and vibration is very good, so the application of medium and thick plates in buildings and bridges can greatly improve the safety. Second, the bearing capacity of medium and thick plate, ASTM A709 structural steel sheet is good, the performance is excellent. The bridge, the automobile girder steel plate, and buildings have strict load-bearing requirements, and it is easy to cause accidents if the steel materials not meet the requirements, so the selection of steel is more stringent.
On 18th December, 2019, BBN Group decorated the office ASTM A709 structural steel sheet building with many kinds of pendant. There were christmas trees, gifts and snowflakes in the logo wall. At the same time, we made a video at the Zhengzhou office to celebrate the coming Christmas holiday. Our ASTM A709 structural steel sheet oversea sales team and market delevopment team wish you Merry Christmas and Happy New Year. Besides, we prepare some meaningful gifts for our old customers.
Oxygen (O) is a harmful element in steel such as ASTM A709 structural steel sheet. Although manganese, silicon, iron and aluminum are added to deoxidize the steel at the end of steelmaking, they can not be removed completely. During the solidification of molten steel, the reaction of oxygen and carbon in the solution will produce carbon monoxide, which can cause bubbles. Oxygen mainly exists in the form of FeO, MnO, SiO2, Al2O3 and other inclusions in the steel, which reduces the strength and plasticity of the steel. Especially, it has serious influence on fatigue strength and impact toughness.
For low alloy high strength steel, the addition of small amounts of V, Ti, Nb, AI and other grain refining elements not only further improves the strength, but also improves the toughness of the steel. In ASTM A709 structural steel sheet, low alloy high strength steel, rare earth element Re is sometimes added to eliminate harmful impurities in the steel, improve the shape and distribution of inclusions, and weaken its cold brittleness. A small amount of alloying elements has a significant effect on improving the mechanical properties of steel. For example, adding only 1% Mn to Q235 becomes Q345 steel, but its strength increases by nearly 40% to 345 MPa.
