Advantages of hot rolling: hot rolling can destroy the casting structure of ingot, refine the grain of steel and eliminate the defects of microstructure, so that the steel structure is dense and the mechanical properties are improved. This improvement is mainly reflected in the rolling direction, so that the A709 grade 50 high strength steel steel is no longer isotropic to some extent; the bubbles, cracks and looseness formed during pouring can also be welded under the action of high temperature and pressure.
Japan is a typical shipping first, and its raw materials are imported from Oceania, central and South America and other Asian countries. Most of the A709 grade 50 high strength steel steel produced is exported to China and other Asian countries, and a small amount is exported to America. Shipping is the main way of its A709 grade 50 high strength steel steel international transportation. According to the data, steel goods account for about 20% of the total sea freight in Japan. The domestic transportation of Japanese steel is mainly truck.
From the name, we can clearly know that seamless pipe is seamless steel pipe, which is different from welded pipe. Seamless pipe is actually a kind of steel with hollow section. A709 grade 50 high strength steel, Seamless pipe has many advantages, such as: 1, the compressive capacity of seamless pipe is very good, the place with high bearing strength will not crack, and its bearing capacity is very good. 2. Seamless pipe has no welding point, so it is more corrosion-resistant and can bear larger pressure.
Q345 is a grade of carbon structural steel. Q is the meaning of yield strength, which A709 grade 50 high strength steel is taken from the initial of Chinese Pinyin of "Qu"; 345 is the value of yield point, in MPa. Q345 refers to carbon structural steel with yield point (σ s) of 345mpa. The following letters indicate the quality level, including A, B, C, D and E. Q345 steel has good comprehensive mechanical properties, low temperature performance, good plasticity and weldability. Q345 steel is usually in hot rolling or normalizing state.
