The Production Process of Wire Rod

The wire rod refers to the hot-rolled round steel with a diameter of 5-22 mm or a profiled steel of considerable section. Since it is delivered in coil form, it is also commonly known as the coil. Common wire product specifications are 5-13mm in diameter. According to the different rolling mills, it can be divided into a high-speed wire rod and ordinary wire rod.

The high-speed wire rod is rolled on high-speed wire rod mill. The production speed is fast and the disk is large (the maximum disk weight can reach 250kg), and the packaging is usually tight and beautiful.

The high-speed wire rod refers to the wire rod rolled by the “high-speed non-twist rolling mill”. The rolling speed is 20-60 m/s, and each weight (disc) is 0.4-0.6 tons (generally three of six heads are seen on the market). In the rolling process, the performance of the product can only be ensured by air cooling on the cooling line.

The general wire rod is rolled by ordinary rolling mills, and the general disc weight is small. One pack is usually packaged by several sections of discs, and the package is looser and messy. Ordinary wire rod mills have been classified as backward production capacity and will be phased out.

The wire is characterized by small cross section and large length, which requires high dimensional accuracy and surface quality. The main rolling processes are:

• Billet: The billet of the wire rod is mainly made of continuous casting billet, and its side length is generally 120~150mm, and the length is generally about 6~12m. In actual production, the quality of continuous casting billet is inspected by visual inspection, electromagnetic induction inspection, and ultrasonic flaw detection;
• Heating:It is generally heated by walking beam The heating requirement is that the oxidative decarburization is small, the billet is not twisted, and no overheating are generated. Modern high-speed wire rod mills are large and long, which requires uniform heating temperature and small temperature fluctuation range.
• Rolling: The cross section of the wire rod is relatively simple, so the degree of specialization of the rolling mill is high. Due to the large extension of the blank to the finished product, the number of rolling stands is relatively large, generally 21 to 28, which are divided into rough rolling units. At present, the export speed of high-speed wire rod mill products has reached more than 100m/s.
• Finishing: Due to the high rolling speed of modern wire rods, the temperature drop during rolling is small or even temperature-raising, so the temperature after wire rod finishing is high. In order to ensure the quality of the product, it is necessary to carry out the roll control cooling. There are pearlite controlled cooling and martensite controlled cooling depending on product use.