Q345钢板指这种材质的屈服强度下限为345MPa，是一种低合金钢，综合力学性能良好，低温性能，易可塑性和焊接性良好，用做中低压容器、油罐、车辆、起重机、矿山机械、电站、桥梁等承受动荷的结构、机械零件、建筑结构、一般金属结构件，热轧或正火状态使用，可用于-40℃以上寒冷地区的各种结构。Q345钢的可塑性（即塑性）和焊接性能良好。如果塑性好，可以加工成各种形状。良好的焊接性能也使其更易于加工，从而节省了加工成本。

Q345 steel plate refers to the yield strength of this material of 345MPa, is a low alloy steel, good comprehensive mechanical properties, low temperature performance, easy plasticity and weldability, used as low pressure containers, oil tanks, vehicles, cranes, mining machinery, power station, bridge structure, mechanical parts, building structure, general metal structure, hot rolled or hot state, can be used in the cold area above-40℃.Q345 steel plasticity (i. e. plasticity) and welding performance.If the plastic is good, it can be processed into various shapes.Good welding performance also make it easier to process, thus saving processing costs.

用于建筑桥梁钢板要求有较高的强度、耐性以及承受机车车辆的载荷和冲击，且要有杰出的抗疲劳性、一定的低温耐性和耐大气腐蚀性。拴焊桥梁用钢还应具有杰出的焊接功用和低的缺口敏感性。

Steel plate for building bridge requires high strength, resistance and load and impact of locomotive and vehicles, and outstanding fatigue resistance, certain low temperature resistance and atmospheric corrosion resistance.Steel for tie-welding bridges shall also have outstanding welding function and low gap sensitivity.

除了主要应用于桥梁，我国很多地标性建筑比如上海环球金融中心、中央电视台新台址建设工程、国家体育场、国家大剧院、上海世博馆、上海世博主题馆、上海世博文化中心、首都国家机场、上海浦东国际机场、上海国际赛车场等都大量使用Q345，作为目前成熟的、综合性能强的钢材，其使用占比非常高，且多以钢板的形式使用。

In addition to mainly used in Bridges, many landmark buildings such as Shanghai global financial center, CCTV new site construction project, national stadium, national grand theatre, Shanghai expo pavilion, Shanghai expo pavilion, Shanghai expo, Shanghai expo culture center, the capital national airport, Shanghai pudong international airport, Shanghai international circuit are used Q345, as the mature, comprehensive performance of steel, its use proportion is very high, and more in the form of steel plate.