中文：

ST523是一种高强度低合金结构钢，属于日本标准中的牌号，对应中国标准中的Q345B。这种钢材具有较高的屈服强度和抗拉强度，同时具有较好的低温韧性，常用于制造大型船舶、桥梁、石油化工等重要结构件。

ST523钢具有较好的加工性能，可以进行焊接、弯曲、切削等加工，而且具有较好的耐腐蚀性，可以在海水中使用。此外，ST523钢还具有较好的低温韧性，可以在较低的温度下保持其强度和稳定性，因此常用于制造大型船舶、桥梁、石油化工等重要结构件。

ST523钢在制造过程中需要进行严格的质量控制和检验，以确保其性能和质量符合要求。此外，ST523钢在应用过程中也需要进行定期的维护和检测，以确保其安全性和可靠性。

英文：

ST523 is a high-strength low-alloy structural steel, which is a brand name in the Japanese standard, corresponding to Q345B in the Chinese standard. This steel has high yield strength and tensile strength, and good low-temperature toughness, which is commonly used for manufacturing important structural parts such as large ships, bridges, and petrochemical plants.

ST523 steel has good processing performance, can be welded, bent, cut and other processes, and has good corrosion resistance, which can be used in sea water. In addition, ST523 steel also has good low-temperature toughness, which can maintain its strength and stability at lower temperatures, so it is commonly used for manufacturing important structural parts such as large ships, bridges, and petrochemical plants.

During the manufacturing process of ST523 steel, strict quality control and inspection are required to ensure its performance and quality meet the requirements. In addition, ST523 steel also needs regular maintenance and testing during the application process to ensure its safety and reliability.