Q345 steel for metal material applications

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Q345 steel has strong comprehensive performance, and there are a variety of special steels developed on this basis, so it is also widely used in the construction industry.

1. For large buildings. With the process of modernization in China, the role of steel in construction is also increasing.

Many landmark buildings in China, such as Shanghai World Financial Center, CCTV new site construction project, National Stadium, National Center for the Performing Arts, Shanghai World Expo Pavilion, Shanghai World Expo Theme Pavilion, Shanghai World Expo Culture Center, Capital National Airport, Shanghai Pudong International Airport, Shanghai International Circuit, etc., are a large number of high-strength steel. As a mature steel with strong comprehensive performance, Q345 has a very high proportion of use, and is mostly used in the form of steel plates.

2. Used for highway Bridges. Bridge steel in our country can be summarized in three stages.

In the first stage, the domestic production of bridge steel in the early days of the founding of the People's Republic of China was not possible. When the bridge steel was imported from the Soviet Union, the Wuhan Yangtze River Bridge was built at that time.

In the second stage, due to political reasons, the Soviet Union stopped supplying low-alloy structural steel for Bridges in China. In 1962, Anshan Iron and Steel Company successfully developed 16Mnq high-strength bridge steel with a yield strength of 340MPa for the construction of Nanjing Yangtze River Bridge.

The third stage is the use of welding steel, welding bridge steel after 60 to 90 years of development materials finally developed, representing the steel number of 15MnVNq, in 1993 for the construction of Jiujiang railway bridge.

3. Used for boilers and pressure vessels, corresponding to the grade Q345R, R is the initial letter of "vessel" pinyin.

4. Used for general structural steel, such as factory buildings, buildings, power lines and other general purpose welding metal structure. The steel has high strength, good welding performance, strong corrosion resistance, can save metal and reduce the weight of equipment, and is gradually replacing ordinary carbon steel to become the mainstream.

5. Based on Q345 steel, Q345GNH steel is suitable for atmospheric corrosion resistant hot rolled, cold rolled steel, steel strip and section steel. It is a kind of inexpensive steel between ordinary steel and stainless steel, and can be used for vehicles, containers, buildings, tower cranes and other structural products. It can also be used as structural steel for bolting, riveting and welding, but the thickness of structural steel used for welding is generally not greater than 16mm.

6. According to corrosion resistance, Q345 steel without special treatment is a steel with good corrosion resistance. The corrosion resistance of this steel is good for the following reasons:

(1) After alloying, the grain is refined, the composition is more uniform, and it is not easy to form a potential difference and electrochemical corrosion;

(2) While improving the weldability, the surface quality of the steel is improved, and the corrosion will not be accelerated because of poor surface quality;

(3) If the use of TMCP technology can further improve the composition uniformity and surface quality of steel, improve corrosion resistance.