Q345是一種鋼材材料。它是低碳合金鋼（C C<0.2%)，綜合性能好，低溫性能好，冷沖壓性能，焊接性能和可切削性能好。廣泛應用于橋梁、車輛、船舶、建筑、壓力容器等。Q代表的是這種材質的屈服，后面的345，就是指這種材質的屈服值，在345MPa左右。并會隨著材質的厚度的增加而使其屈服值減小。

　　牌號CSiMnPSVNbAlTiCrNiCuQ345A≤0.20≤0.50≤1.70≤0.035≤0.035≤0.15≤0.07-≤0.20≤0.30≤0.50≤0.30Q345B≤0.20≤0.50≤1.70≤0.0350.035≤0.15≤0.07-≤0.20≤0.30≤0.50≤0.30Q345C ≤ 0.20 ≤ 0.50 ≤ 1.70 ≤ 0.030 ≤ 0.15 ≤ 0.07 ≥ 0.20 ≤ 0.30 ≤ 0.50 ≤ 0.0.18 ≤ 0.70 ≤ 0.030 ≤ 0.07 ≤ 0.0.30 ≤ 0.50.30q3q3q3q3q3q.30 ≤ 0.30 ≤ 0.30 ≤ 0.30q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q3q.50 ≤ 0.18≤ 0.50≤1.70≤0.02≤0.15≤0.015≤0.30≤0.50≤0.30

　　Q345B板可以稱為Q345B Youte鋼板，Q345B鋼板，Q345B滾動板，Q345B開放式平板電腦，Q345B，Q345B，Q345B冷卷板，Q345B，Q345B熱卷板，Q345B，Q345B薄板，Q345B厚板，Q345B厚板，Q345B厚度厚，厚度厚，厚度厚度， 。

　　Q345B rods can be called Q345B Youte Steel Round Steel, Q345B Round Steel, Q345B Circle, Q345B wire, Q345B silk material, Q345B forging circle, Q345B round stick, Q345B black rod, Q345B light circle, Q345B, Q345B Light round, Q345B hot -滾動鋼，Q345B滾動圓圈，Q345B冷張力鋼等。

　　Q345B pipes can be called Q345B Youte Steel Pipe, Q345B steel pipe, Q345B Youte steel seamless pipe, Q345B seamless pipe, Q345B You special steel welded pipe, Q345B tube, Q345B Youte steel precision pipe, Q345B precision pipe, Q345B capillary pipe, etc.本質