Mechanical properties of 20MnSi alloy steel plate

20MnSi alloy steel plate belongs to hypoeutectoid steel, and its matrix structure is ferrite + pearlite. Among them, the relative content of ferrite and pearlite, as well as their structure, distribution and grain size directly affect the mechanical properties of 20MnSi steel. The higher the pearlite content, the finer the pearlite clusters and the larger the grain size (the finer the grains), the higher the strength of the steel; vice versa. When the chemical composition is fixed, the internal structure of the steel directly affects the mechanical properties.

While the rolling process changes the shape of the 20MnSi steel, it also changes the internal structure of the steel through structural changes such as work hardening, crystallization, and recovery, and ultimately determines the mechanical properties of the 20MnSi alloy steel plate.

Based on these theories, the content of alloying elements in small-sized 20MnSi alloy steel plate should be low; the content of alloying elements in large-sized 20MnSi alloy steel plate should be high, mainly due to two reasons. The first is the rolling reduction ratio. The rolling reduction ratio of small-sized steel is large; the small rolling reduction ratio of large-sized steel can make the structure of the steel compact and improve the mechanical properties of the steel. The second is the cooling rate, the cooling rate of large-size steel is slow. The fast cooling rate can easily refine the grains so as to improve the mechanical properties of the steel.