How is H-beam rolled? What is a “universal mill”?

• What is H-beam?

H-beam is optimized and developed from I-beam, and it is an economical section steel with better section mechanical properties. H-beam section shape is economical and reasonable, with good mechanical properties, and the section is named after the English letter “H”.

H-beams are divided into hot-rolled H-beams and welded H-beams

• H-beam rolling process

The rolling of strip steel is very easy to understand, and it is simply rolled with two upper and lower rolls.

H-beam is just like its name, like an H letter, how to roll such a complex shape of steel, this requires a special rolling technology, we call it pass rolling.

• How H-beam is rolled

1. Rough rolling

The billet is first rolled into an approximate H shape with a two-roller with a pass. The red part in the figure below is the cross-sectional shape of the billet after entering each corresponding pass position. The second and third holes from left to right are identical, and one of them is a spare hole during production.

• H-beam rolling process

Process introduction：

Is the universal mill universal? In fact, it is not. It means that the finishing rolling process of section steel can be applied to more sizes, but it is absolutely impossible to leave the production of section steel.

• What is a universal rolling mill?

The difference between the universal rolling mill and the ordinary rolling mill is that a pair of vertical rolls are added on the basis of the two rolls. The function of the vertical rolls is to control the size and shape of the left and right sides.

Without further ado, let’s take a look at the basic structure of the most advanced universal rolling mill in China with a simplified three-dimensional diagram.

Note:

1. The green part of the figure is the bearing box of the flat roll and the vertical roll, and the blue part is the roll.

2. The vertical roller does not need to be driven, it is a passive roller. The horizontal roll, like the ordinary rolling mill, has a flat section on the right side, which we call the flat head, which forms a transmission cooperation with the shaft sleeve.

Structure of universal rolling mill

1.The structure of the universal rolling mill is different from that of the ordinary two-high rolling mill

With the addition of a pair of vertical rolls, the structure of the universal rolling mill is also different. Compared with the ordinary two-high rolling mill, there is a horizontal arch (frame) on the left and right of the universal rolling mill to carry the vertical roll pressure.

2.The assembly of the universal rolling mill is more complicated than that of the ordinary two-high rolling mill

The connection of the arches on both sides requires the use of four long prestressed tensioning hydraulic cylinders. (Of course, there are also beams that are sleeved on the corresponding hydraulic cylinders. In order to clearly see the four hydraulic cylinders, we will omit them.)

3. Side view of the universal mill

• How “universal” is the universal rolling mill?

What else can a universal rolling mill produce besides H-beams?

These products have high precision requirements on the lateral dimension and the straightness of the flange. I really don’t know how to produce them without the universal rolling mill. Of course, there are many other products with strange shapes that we won’t go into details.