Endless rolling has a series of obvious advantages, such as high production efficiency, improving dimensional accuracy by reducing the loss of cutting head and tail to improve the yield, overcoming the dimensional deviation of the head and tail of the rolling piece, reducing the impact of the head and tail of the rolling piece on the motor, transmission system, roll, guide guard and reducing accidents. It is highly praised and researched by the steel rolling workers.

Currently, there are two types of endless rolling technology for rebar and wire rod.

1. EWR headless rolling technology  

To cut the slab first, and then heat it. After it is released from the furnace, or after the roughing rolling mill, the two front and back steel slabs (rolled parts) are welded together end to end to achieve endless rolling. This technology of endless rolling by welding is called EWR, which was developed by Japanese manufacturers and first applied. China Tangshan Iron & Steel, Xing Steel, Bayi Iron & Steel have tried it out.

The EWR endless rolling technology means the slab that was originally headless and tailless was cut off first, and then welds it into a headless and tailless workpiece. This is really a helpless solution to the mismatch between the speed of the continuous casting machine and the rolling mill.

In addition to enjoying the many benefits of endless rolling, this process also brings a series of difficult problems. First and foremost is the complexity of welding equipment and the increase of accident points, which affect the operating rate in the initial stage of commissioning. After short-term trials, manufacturers such as Tangshan Iron and Steel and Bayi Iron and Steel have abandoned their efforts to further improve this technology and reverted to the original single-rolling operation. This affected other manufacturers' views on the EWR headless rolling process, and later they are discouraged.

2. The Luna endless rolling process

It is developed by Danieli, Italy, and has been applied to Luna endless rolling by Udine, Italy. It is characterized by connecting the continuous caster and continuous rolling mill in a production line, the slab is not cut off, and after the induction heating of the tunnel furnace, direct rolling is realized. After rolling, it is sheared to a fixed length for cooling and subsequent processing.

Compared with the EWR process, the Luna headless rolling process avoids the embarrassment of cutting and re welding. It is a major process innovation in the field of bar and wire production and represents the future development direction of bar and wire production technology. However, the disadvantage of the Luna process is that it still needs to use a longer tunnel furnace for induction heating, and its construction and operating costs are higher.

In general, there is still a need to continue research on rebar and wire rod endless rolling technology.