I-beam is mainly divided into ordinary I-beam, light I-beam and wide flange I-beam. According to the height ratio of flange to web, it is divided into wide, medium and narrow flange I-beams. The specifications of the first two are 10-60, that is, the corresponding height is 10 cm-60 cm. At the same height, the light I-beam has narrow flange, thin web and light weight. Wide flange I-beam, also known as H-beam, is characterized by two parallel legs and no inclination on the inner side of the legs. It belongs to economic section steel and is rolled on four high universal mill, so it is also called “universal I-beam”. Ordinary I-beam and light I-beam have formed national standards.