H-beam is a new type of steel for economic construction. H-beam has economical and reasonable cross-sectional shape, good mechanical properties, uniform extension of each point on the cross-section and small internal stress during rolling. Compared with ordinary I-beam, H-beam has the advantages of large cross-sectional modulus, light weight and metal saving, which can reduce the building structure by 30-40%. In addition, because its legs are parallel to the inner and outer sides and the leg ends are right angles, the welding and riveting work can be saved by 25%. It is often