Wire rod production process
The wire rod is generally produced by high wire, and its production process can be divided into the following steps:
- Heat the billet to a temperature above 1100 degrees Celsius through a walking furnace;
- The heated billet is released from the furnace and descaled by high-pressure water;
- Enter the rough rolling mill for rolling, and the rough rolling mill is a hot continuous rolling unit;
- The rolled piece after rough rolling enters the water cooling section for cooling to control its internal metallographic structure;
- After leaving the water cooling section, enter the intermediate rolling mill and the finishing mill for further rolling;
- The rolled piece after finishing rolling is spit out from the laying machine to form a coil;
- The coiled wire is cooled and moved forward in the air cooling section;
- At the end of the air cooling section, the wire is rolled into a reel by the reel collector;
- The wire rod after being rolled into a reel is sent to the baler for baling;
- Enter the finished product warehouse.
Wire rod cooling methods
The cooling method after wire rod rolling can be divided into two categories: one is called natural cooling method; the other is called controlled cooling method.
Natural cooling
Natural cooling method, also known as the natural stack cooling method, that is, after the wire rod is rolled out from the finished stand of the finishing mill, it is coiled into a coil by a coiler, and then hung on a hook conveyor, and is naturally cooled or cooled during operation. It is transferred to the wire product storage yard through roller table, chain conveyor and other equipment for natural cooling. The basic feature of the natural cooling method is that the wire is subjected to natural stack cooling at high temperature.
However, if the cooling time is long, the scale of iron oxide will be serious, and the cooling speed of the inner and outer layers of the wire coil is different, resulting in uneven structure and properties of the whole length of the wire, and the fluctuation range is about 20%.
Controlled cooling
The controlled cooling method means that the cooling after the wire rod rolling is carried out under controlled conditions. Its basic feature is that the rolled wire is immediately supercooled from high temperature to the transformation temperature (usually 650-800) required for the formation of sorbite transformation, and then the coil is cooled at different cooling rates. This avoids the disadvantages of the natural cooling method and significantly improves the quality of the wire.
There are many kinds of controlled cooling methods, mainly including: Steyrmore method, Schlohmann method, intermittent water cooling method, ED method, EDC method, fluidized cooling bed method, etc. Each of these methods has advantages and disadvantages. Among them, the most commonly used is the Steyrmore method. According to reports, there are more than 150 Steyrmore cooling lines in the world.
