Medium and heavy plate rolling

Rolling

Rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce thickness and to make the thickness of the finished product uniform. The concept is similar to rolling a rolling pin to flatten dough. A four-high rolling mill, for example, of a type commonly used in the manufacture of steel, has two small and two large cylinders, forming what is known as a back-up roll configuration, meaning that the smaller cylinders are backed up by the larger cylinders, which provide greater pressure, resulting in a greater force to reduce the thickness of the stock material.

When rolling thick stock, such as hot-rolled steel plate, the process is often referred to as plate rolling. These plate-rolling processes may involve two or three rolls, with the upper roll driven and the bottom roll or the two side rolls patterned, depending on the desired outcome. Pressure applied to the rollers ensures the stock is formed into its desired shape and size.

Another rolling process that may use a steel plate as its stock material is heavy plate rolling, or thick plate rolling. This process is used to produce parts that are too thick or too large for traditional rolling processes. It is used to produce thick-wall parts, such as pressure vessels and other heavy steel components. In this process, two cylinders, one of which is connected to a stationary position such as the floor, are used to apply pressure to the steel plate. The cylinders are rotated in opposite directions, allowing the rolling force to form the steel plate into its desired shape.

In order to roll a steel plate, aflat-surface rolling machine, which looks like a traditional rolling pin and is also referred to as an infinite-pass rolling machine, is commonly used. This machine uses rotating rollers to reduce the steel plate thickness while rolling the steel along the entire length of the machine. This process can achieve superior results in terms of thickness uniformity and surface finish, making it a popular choice for many modern manufacturing applications.

Today, rolling is widely used in a variety of industries, from aerospace to automotive. In general, the advantages of rolling include improved mechanical properties of the metal; improved surface finish; improved dimensional accuracy; reduced waste; and greater productivity, meaning that fewer passes are required to achieve the desired outcome. As such, rolling is an effective and efficient way to produce high-quality metal parts with a wide variety of applications.

Hot rolled steel plate refers to the production and processing of steel plate products. Unlike cold rolling, hot rolling does not need to pass through rolling and stretching, thus the original steel piece can be directly used as a rolled sheet. Hot rolling process generally includes annealing, descaling, cooling, normalizing and other processes such as coating.

Hot rolling can be divided into slab, hot strip and hot profile rolling. Slab hot rolling is carried out at the beginning of heavy slab rolling machine. The rolled slab is cooled and then heated or pickled and then passivized or hot-rolled again, which is finally cut into hot-rolled steel plates or coiled into hot-rolled coils, and then hot-rolled into hot-rolled steel plates or hot-rolled coils of different thicknesses. The hot strip is hot rolled from the hot slab. That is, the slab is heated again, and then forwarded and rolled by the stacking machine, which is then cut into hot-rolled steel plates or rolled into coils again, and then hot-rolled into hot-rolled steel.

The hot rolling of heavy plates is a kind of cold rolling which is carried out by rolling at normal temperature. The thickness of heavy plate is usually stored between 6-40mm. It is usually hot rolled from heavy slab and hot rolled from hot-rolled coil (including hot-rolled steel strips). The steel plate is sent to the furnace by roller after pre-tension, heating, constant temperature and then cooled step by step until it reaches the normal temperature before finally uncoiling and cutting.

More and more steel plants are adopting heavy rolling process to produce steel products. Compared with the traditional cold rolling process, the advantages of the heavy rolling process are higher production efficiency, lower production cost, less oxidation of steel, not easy to produce hardening of steel, and easy to improve the productivity and quality of steel products.