Billet induction heating furnace you won’t want to miss !
After drawing from the continuous casting machine, the billet surface temperature is 750-800 degree C., the core temperature can be up to 950-1000 degree C.One of the fundamental principle of induction heating is skin effect, that is, heating from the surface to the core gradually. In fact, one-third of the billet does not require to increase heat, according to the different billet interface scale, select the different frequency, you can get the best heating power. Billet induction heating furnace heating technology guidelines include heating temperature, heating speed, heating time, heating criteria.
In the early heating process, the billet surface will have temperature difference from the billet core. The surface temperature is high, it will expand big; the core temperature is low, it will expand small. But the surface and core is one piece of metal than can not be divided into two parts. So the the surface will limit the core and give tensile stress to the core. This stress is called “temperature stress” or “thermal stress” is obvious.
The heating speed of billet induction heating furnace is bigger, the temperature difference of surface and core is bigger. When the temperature stress is within the elastic limit of steel, there is no effect on the steel quality. As with the temperature difference reduction and elimination, the stress will naturally not see. When the temperature stress exceeds the elastic limit of steel, the billet will attack the plastic deformation. After the temperature difference eliminated, the stress will not be completely lose, that is called residual stress. If the temperature stress is greater beyond the strength limit of steel, it will break in the heating process.
At this time the temperature stress on the billet in the middle of the greater harm, because the middle of the tensile stress, the general tensile strength of steel is much lower than its compression strength, so the middle of the temperature stress is easy to constitute internal cracks.
If the plasticity of steel is excellent, even in the heating process, there is a large surface and core temperature difference, it can only lead to plastic deformation, but there is no billet cracks at any running speed. If the thermal conductivity of the steel is good, the temperature difference from surface to the core in the heating process is small, so that the plastic deformation or cracking caused by the temperature stress during heating may be small.
Low carbon steel thermal conductivity is big, high carbon steel and alloy steel thermal conductivity is small, so high carbon steel and alloy steel will have larger temperature difference during heating process. The plastic of these steel is poor and brittle. So they will easily crack during heating in the furnace.
Contact person: Hailee Ma
Phone: 0086-18932783253(whatsapp, wechat)
Specialist of induction heating equipment and system in China; Glad to be your business partner in induction heating field.
Post time: 10-09-2017