Pass design of I-beam
The specification of I-beam is expressed in cm of waist width. For example, the waist width of No. 10 I-beam is 10cm. The types of I-beam include hot-rolled ordinary I-beam, light I-beam and wide parallel leg I-beam (H-beam). The waist width of hot-rolled ordinary I-beam in China is 100 ~ 630mm, expressed as 1 ~ 63, and the slope of inner wall of leg is 1:6. The pass system of rolling I-beam includes direct pass system, cross pass system and mixed pass system. In addition, special rolling method can be adopted for I-beam.
(1) Direct rolling pass system. Direct rolling pass system refers to the pass system in which the two open legs of the I-beam pass are located on the same side of the roll axis at the same time, and the waist is parallel to the roll axis.
The utility model has the advantages that the axial force of the roll is small, the axial movement is small, the working inclined plane is not required, the length of the roll body occupied by the pass is small, and more passes can be matched under the condition of a certain length of the roll body.
(2) Cross rolling pass system. This pass system means that the two open legs of the I-beam pass are not on the same side of the waist at the same time, and the waist has an included angle with the horizontal axis.
(3) Mixed pass system. According to the characteristics of rolling mills and products, in order to give full play to the advantages of their respective systems and overcome their disadvantages, hybrid pass system is often adopted, that is, the combination of more than two systems. For example, the straight leg cross rolling pass system is adopted for the finished hole and the front hole of the finished product, and the curved leg cross rolling system is adopted for other passes; Or the rough rolling hole adopts the direct rolling system, and the last 3 ~ 4 finish rolling holes adopt the straight leg oblique binding hole, etc.
(4) Special rolling method. For some reason, when it is difficult to roll the required I-beam with the usual rolling method, the 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 wide I-beam is required to be rolled, the wave rolling method can be adopted; For another example, when the blank is wide and it is required to roll small I-beam, negative spread rolling can be adopted.