I beam
Hot rolled ordinary joist steel, also called steel beam, is strip steel with I-shape section. Its section size is represented as waist height (h) x waist thickness (d) mm, such as waist height **mm, waist width **mm. Thick waist is marked as "I-shape". Another tag method is type marked, that is, waist height showed as centimeters, such as 16#. I-shape steel with same height but different waist thickness and legs width different beams will be recognized with type on right side, like #, etc. 

Hot rolled I-shape beams can be divided into common i-steel and light beams. 
(1) Common i-steel 
Main purpose: Ordinary beams are widely used in various building structures, Bridges, vehicles, support and machinery, etc. 
(2) Light beams 
Flange of common i-steel and light beams are gradually becoming thinner from root to the edge with certain angle. Compared with ordinary beams, hot rolling light beams has wider leg and thinner waist in same wait height conditions. Guaranteed the bearing capacity, the light beams have better stability, metal saving and better economic effect than ordinary beams. 
Main use: The same with ordinary beams, it is mainly used in factories, Bridges and other large structures and vehicle manufacturing, etc.

Parameters of the specification