Hot-rolled section steel has the characteristics of large production scale, high efficiency, low energy consumption and low cost; therefore, hot-rolled section steel production is the main method. This paper introduces the rolling methods of the following types of steel:
1) Ordinary rolling method
That is, the ordinary rolling method carried out on a general two-roll or three-roll mill. The pass is composed of the groove of two rolls, which can produce generally simple, special-shaped and longitudinal rolling periodic section steel. This rolling method and equipment are relatively simple, so many section steel rolling mills are still used at present.
2) Multi-roll rolling method
The characteristics of the multi-roll rolling method are: the pass is composed of more than three roll grooves, thereby reducing the adverse effect of closed grooves, and the roll diameter difference is also reduced, which can roll out economical section steel with parallel inner and outer sides of the flange. The flange height can be increased, and it can also produce special-shaped section products that cannot be produced by ordinary rolling methods. The rolling precision is high, and the roll wear, energy consumption, and rolling residue should be reduced, among which H-beam belongs to this category.
3) Hot bending method
The first half of it is to roll the billet into a flat-strip shape close to the shape of the finished section, and then bend it while hot in the subsequent pass. It can be produced on general rolling mills or in-line horizontal-vertical rolling mills, and can roll bent section steels that cannot be obtained by general methods.
4) Hot rolling – longitudinal slitting method
Its characteristics are: firstly design the products with asymmetrical sections that are difficult to roll into symmetrical sections, or design small-section products into parallel-type large-section products to improve the production capacity of the rolling mill, and then use the disc on the rolling mill or after cooling. Cut for longitudinal section.
5) Hot rolling – cold drawing (rolling) method
This method can produce high-precision profiles. The mechanical properties and surface quality of the products are higher than those of ordinary hot-rolled profiles. The precision can reach 3~4 grades, and the surface finish can reach 5~7 grades, which can be directly used for various mechanical parts. This method can improve work efficiency and reduce metal consumption, and is especially suitable for the method of transforming old rolling mills for small batch and multi-variety production. The method is as follows: firstly hot-rolled to form, leaving a cold working allowance, and then pickling, alkali washing, water washing, lubricating, and cold drawing (rolling) into a product.
6) Hot and cold bending forming method
The hot-rolled and cold-rolled strips are used as raw materials, and the strips are subjected to transverse bending deformation by passing through rolls with a certain groove shape and rotating to obtain the desired cross-sectional shape.
