The chemical composition of Q345D seamless steel pipe is as follows: C ≤ 0.18, Si ≤ 0.50, Mn ≤ 1.70, P ≤ 0.030, S≤ 0.025, Nb ≤ 0.07, V ≤ 0.15, Ti ≤ 0.20, Cr ≤ 0.30, Ni ≤ 0.50, Cu ≤ 0.30, N ≤ 0.012, Mo ≤ 0.10, Al ≥ 0.015. ASTM A709 high strength steel, Q345D seamless steel pipe has good comprehensive mechanical properties, low temperature impact toughness, corrosion resistance, cold stamping, machinability and weldability. Q345D seamless steel pipe is widely used in welding structures, such as bridges, vehicles, ships, pipelines, boilers, large vessels, etc..
In September, China's apparent consumption of crude steel was 94.38 million tons, an increase of 15.58 million tons or 19.8% year-on-year. It has exceeded 90 million tons for five consecutive months. From January to September, China's apparent crude steel consumption was 770 million tons, an increase of 63.14 million tons or 8.9% year-on-year. In terms of growth rate, the apparent consumption of hot-rolled sheet and coated sheet (strip) from January to September increased by more than 40% year-on-year, and the growth rates were 42.6% and 42.0% respectively; railway steel and electrical steel strips fell year-on-year, with a decline. They are 12.8% and 1.4% respectively.
The weight of seamless steel pipe is only 1 / 5 of that of square steel. Seamless steel pipe corrosion resistance acid, alkali, salt and atmospheric environment corrosion, high temperature resistance, good impact and fatigue resistance, do not need regular maintenance. The effective service life of product ASTM A709 high strength steel more than 15 years.
Medium and heavy plate is widely used in construction engineering, machinery manufacturing, container manufacturing, shipbuilding, bridge construction and other fields. The surface quality of medium and heavy plate mainly refers to its surface smoothness, surface defects, etc., which is one of the main quality indexes of medium and heavy plate. The surface quality of ASTM A709 high strength steel, medium and heavy plate not only affects the appearance of the products, but also reduces the corrosion resistance, wear resistance, fatigue limit and other properties of the steel plate.
