Steel plate materials for shipbuilding mainly include carbon structural steel and low-alloy high-strength steel. Among them, carbon structural steel is the most commonly used one, accounting for more than 70% of the total steel for shipbuilding. Its main feature is that it contains high-carbon elements, usually between 0.07% and 0.15%, and also contains a certain amount of elements such as manganese, silicon and sulfur. The control of these elements can effectively improve the mechanical properties and machinability of steel, improve its strength and toughness, and reduce its cold brittleness. Marine steel plates are divided into ordinary structural steel plates and high-strength structural steel plates. Ordinary structural steel plates generally use carbon structural steel, low-alloy structural steel and heat-resistant structural steel, while high-strength structural steel plates use microalloyed low-carbon steel or weather-resistant low-alloy steel.