The DBTT of low carbon steel is influenced by both the carbon content and the presence of alloying elements or impurities. Elements like manganese and nickel can lower the DBTT and improve toughness, while higher levels of carbon, phosphorus, sulfur, and oxygen tend to raise it, making the steel more brittle at lower temperatures. The following studies may be helpful: https://doi.org/10.1007/s11223-019-00075-8; https://doi.org/10.3390/ma14071634; https://doi.org/10.1007/s12540-021-01053-z; The effect of chemical composition on the DBTT in low-carbon steel alloys plays a decisive role in determining the microstructure of the material. Generally, low-carbon steels exhibit a ferrite-pearlite microstructure, and refining the grain size can lower the DBTT, thereby improving impact toughness. For instance, a finer grain structure significantly enhances resistance to brittleness. This phenomenon can be explained by the Hall-Petch relationship, which states that as grain size decreases, the material's yield strength increases, and the fracture stress rises accordingly. Additionally, the inclusion of elements like aluminum or manganese in the chemical composition of low-carbon steels also affects the DBTT. For example, an increase in manganese content enhances the ductility of the steel, lowering the transition temperature. The addition of aluminum can further reduce the DBTT in ferritic structures, improving the material's thermal resilience. These factors can be optimized according to the steel's intended applications and required strength characteristics.