High-quality carbon structural steel plates, also known as carbon structural steel plates in the industry, are steel plates specially used to manufacture various important parts components, which require good comprehensive properties and certain chemical composition in machine building or engineering construction.
First, the main difference between high-quality carbon structural steel and ordinary carbon structural steel is that the chemical composition of the former should meet the requirements of steel grade standard, and its chemical composition should generally be C≤0.17-0.25%, Si≤0.17-0.37%, Mn≤0.50-1.20%, P≤0.035%, S≤0.035%, and the sulfur, phosphorus and impurity content should meet the relevant requirements.
Second, the carbon content of high-quality carbon structural steel should be controlled to a low level of 0.17-0.25%. As the carbon content increases, the thickness of the hardened layer of the steel increases, so if the carbon content is too high, the hardness of the surface and the inner layer of the part cannot be effectively used, and the toughness is too poor, which affects the use of the part to a certain extent.
Third, in addition to the above three points, the mechanical properties of high-quality carbon structural steel also have certain requirements. Generally, the yield strength value of the steel plate should be above 245MPa and the tensile strength should be between 315-440MPa.
Fourth, in order to improve the overall performance of the steel plate, Nb, V and Ti microalloying elements need to be appropriately added. According to different steel grades, the content can be controlled between 0.01-0.06%. Microalloying elements can reduce the impurity content of steel and refine grain size, improve the decisive strength and hardness of steel, as well as the performance of welding joint and heat treatment.
Finally, in order to ensure the good mechanical properties of high-quality carbon structural steel plates in engineering application, the controlling of steel rolling and heat treatment processes are also very important. Generally, hot rolling can reduce the yield stress of steel and the thickness of the hardened surface layer, while the cold rolling is mainly used to adjust the mechanical properties of the steel and reduce the hardness of the hardened surface layer. Heat treatment is mainly used to adjust the strength and toughness of the steel, and the quenching is mainly used to obtain better yield strength, while the tempering is mainly used to obtain lower yield strength.
In summary, high-quality carbon structural steel plates must meet the requirements of steel grade standard in terms of chemical composition, carbon content, mechanical properties, microalloying elements, steel rolling and heat treatment, which can ensure the use safety and normal of engineering application parts.
