Oxygen is a harmful element in A709 Grade 50 size list steel. With the increase of oxygen content, the strength of A709 Grade 50 size list steel increased, but the plasticity, especially the toughness, decreased significantly, and the weldability became worse. The presence of oxygen causes hot brittleness of A709 Grade 50 size list steel.
Q345qC steel plate is the steel plate of bridge structure, the implementation standard is GB / T 714-2015 standard. A709 Grade 50 size list, Q345qC-Z25 steel: Q represents the yield strength, 345 represents the small yield strength, the unit is MPa, q is short for the bridge, C quality grade, corresponding to the corresponding impact temperature and impact work value, Z is the Z-direction performance that is the performance of the steel plate thickness direction, Z25 is the Z-direction Performance level requirements.
The global share of my country's steel production has increased substantially. In the first nine months of 2020, my country's crude steel output accounted for 58% of the world's total, pig iron accounted for 69%, and imported iron ore accounted for 71% of global iron ore exports. "Such a high proportion is a manifestation of the effective control of the epidemic situation in our country and the strong demand. As the situation of epidemic prevention and control in various countries gradually improves, the proportion of my country's output will gradually decline." Luo Tiejun said.