What is the reheating furnace temperature system?

The temperature system of reheating furnace refers to the change of furnace temperature with time when steel is heated in the furnace. For Continuous  Reheating Furnace and Walking Beam Reheating furnaces, the temperature changes along the length of the furnace.

Because of the difference of steel grade, section size, charging temperature and rolling process, the temperature system adopted is also different. There are one-stage, two-stage, three-stage and multi-stage temperature systems in use at present.

One-stage temperature system is to heat steel in a constant temperature furnace. The surface and center temperatures of steel gradually rise to the required temperatures. Its advantages are fast heating speed, short heating time and high production. The disadvantage is that it is not suitable for billets with poor thermal conductivity, low plasticity, and section size.

The two-stage temperature system is that steel is heated in two different temperature zones or at two different heating speeds. According to the specific conditions, two-stage heating can be composed of the heating section and soaking section, as well as preheating section and heating section. The former is suitable for billets with good thermal conductivity and large cross-section, while the latter is suitable for low or medium plastic billets with poor thermal conductivity and small cross-section.

The three-stage temperature system is heated at three different heating speeds. The temperature system consists of the preheating section, heating section, and soaking section. Its advantages are slow heating speed, low-temperature stress, low tail temperature and low fuel consumption in the preheating section. The heating speed of the heating section is fast, which can reduce oxidation and decarbonization, and increase furnace output. In the soaking section, the surface temperature of steel hardly rises, so it can keep warm for a long time. It is easy to eliminate or alleviate the microstructural defects of steel and ensure uniform heating temperature. This temperature regime is suitable for heating various steels, especially for heating alloy steels with a large cross-section and low plasticity.