Q345b角钢含义：
Q代表的是这种材质的屈服，345指这种材质的屈服值，在345左右。并会随着材质的厚度的增加而使其屈服值减小。类同于Q235的命名方法。
Q345A，Q355C，Q345C，Q345D，Q345E。这是等级的区分，所代表的，主要是冲击的温度有所不同而Q345A级，是不做冲击;Q355C级，是20度常温冲击;Q345C级，是0度冲击;Q345D级，是－20度冲;Q345E级，是－40度冲击。在不同的冲击温度，冲击的数值也有所不同。在板材里，属低合金系列。在低合金的材质里，此种材质为最普通的
Q355C角钢规格表
等边角钢规格：                  材质                             长度                                                 
50*50*（3-6）              Q355C.Q345C.Q345D                     6-12                                          
63*63*（4-10）             Q355C.Q345C.Q345D                     6-12                                            
70*70*（4-12）             Q355C.Q345C.Q345D                     6-12                                          
75*75*（5-10）             Q355C.Q345C.Q345D                     6-12                                         
80*80*（8-12）             Q355C.Q345C.Q345D                     6-12                                           
90*90*（6-7）              Q355C.Q345C.Q345D                     6-12                                             
100*100*（6-16）           Q355C.Q345C.Q345D                     6-12                                                
110*110*（7-14）           Q355C.Q345C.Q345D                     6-12                                               
125*125*（10-14）          Q355C.Q345C.Q345D                     6-12                                                
140*140*（10-16）          Q355C.Q345C.Q345D                     6-12                                                
160*160*（10-16）          Q355C.Q345C.Q345D                     6-12                                                
180*180*（12-18）          Q355C.Q345C.Q345D                     6-12                                         
200*200*（14-16）          Q355C.Q345C.Q345D                     6-12