Universal Beam

I-beams, also known as steel beams, are long strips of steel with I-shaped sections. I - beams are divided into ordinary I - beams and light I - beams. It is a section steel with an I-shape.

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

The specifications of the I-beam are expressed by the value of the waist width in centimeters, such as No. 10 I-beam, whose waist width is 10cm. The types of I-beams are hot rolled ordinary I-beams, light I-beams, and wide parallel leg I-beams (H-beams). The waist width of Chinese hot-rolled ordinary I-beam is 100 ~ 630mm, which is expressed as No.10 ~ No.63, and the slope of the inner side wall of the leg is 1:6. The pass system of rolling I - beam includes straight rolling pass system, diagonal rolling pass system and mixed pass system. In addition, I - beam can also use a special rolling method.

(1) straight rolling pass system. The straight rolling pass system refers to the pass system in which the two open legs of the I-beam pass are at the same side of the roll axis at the same time and the waist is parallel to the roll axis.

Its advantages are the rolling roller axial force is small, small axial channeling, do not need to work inclined plane, the pass occupies the length of the roll body is small, in a certain length of the roll body can be more with the pass.

(2) cross rolling pass system. This kind of pass system refers to the two open legs of the I-beam pass are not in the same side of the waist at the same time, and the waist has an Angle with the horizontal axis.

(3) Mixed pass system. According to the characteristics of rolling mill and products, in order to give full play to the advantages of each system and overcome the disadvantages, the mixed pass system is often used, that is, the combination of two or more systems. For example, the finished hole and the finished front hole adopt the straight leg diagonal rolling pass system, and other passes adopt the bent leg diagonal rolling system; Or rough rolling hole using straight rolling system, the last 3 ~ 4 fine rolling holes using straight leg oblique piercing.

(4) Special rolling method. For some reason it is difficult to roll out the required I-beam with the usual rolling method, special rolling method can be used to make full use of the skills of uneven deformation and pass design. For example, when the billet section is narrow and the wider I beam is required, the wave rolling method can be used; And when the billet is wider and smaller I beam is required, negative wide spread rolling can be used.

Whether the I-section steel is ordinary or light, because the section size is relatively high and narrow, the moment of inertia of the two main axes of the section is large, so it can only be directly used in the web plane bending members or it is composed of lattice stressed members. On the axial compression member or perpendicular to the web plane and bending members are not suitable, which makes it in the application range has a great limitation. I - beams are widely used in buildings and other metal structures.

Ordinary I-beam, light I-beam, because the section size are relatively high and narrow, so the moment of inertia of the two main axes of the section is relatively different, which makes it in the application range has a great limitation. The use of I-beam should be selected according to the requirements of the design drawings.

The selection of I-steel in the structural design should be based on its mechanical properties, chemical properties, weldable properties, structural size and other reasonable selection of I-steel for use.

The specification is expressed by height × leg thickness × waist thickness, and the main size of the specification can also be expressed by the number. For example, No. 18 I-beam indicates the height of 18 cm I-beam. If the height of the same I-beam, can be added after the number of Angle code a or b or c to indicate, such as 36a, 36b, 36c, etc. It is divided into ordinary I - beams, lightweight I - beams and wide flange I - beams. According to the height ratio of flange and web, it can be divided into wide, medium and narrow wide flange I-beams. The specifications of the first two are 10-60, that is, the corresponding height is 10-60 cm.