July 14, 2023
Concept of forging
Forging includes free forging, die forging, extrusion, rolling, cold heading, cold punching, rolling expansion, and many other process methods, in addition to cold heading, cold punching at room temperature, regardless of the forging method, will want to forge the metal billet pre-heating, in order to make the metal has good plasticity, low deformation resistance. After forging the metal, the organization is denser, with higher mechanical properties.
General metal forging billet heating temperature, depending on the recrystallization temperature of the metal. The temperature of forging is closely related to the nature of the metal. Steel recrystallization temperature of about 460 ℃. 300-800 ℃ generally known as warm forging; steel hot forging according to the differences in alloys generally between 800-1200 ℃. For aluminum and aluminum alloys, the general forging temperature of about 400 ℃; copper and copper alloys forging temperature of 750-900 ℃; titanium and titanium alloys forging temperature is usually higher than 1000 ℃.
It goes without saying that metal billets must be heated before forging. All can make the metal temperature rise to the forging process requirements of the heat source can be utilized, but the choice of heating equipment still needs to consider the economics of energy, heating equipment construction of the input cost, the possibility of controlling the heating temperature, stability, in order to meet the requirements of environmental protection put forward.
Introduction to induction heating
Induction heating is mostly used in many fields such as surface quenching of industrial metal parts, metal melting, bar penetrating heat, tool welding, etc. It is to make the workpiece produce a certain amount of induced current internally to form eddy currents, which rapidly heats up the surface of the parts to achieve the effect of rapid heating of the surface, or even the effect of heat penetration and melting.
The basic principle of induction heating is to put the workpiece on a copper tube made of an inductor, inductor into a certain frequency of alternating current, the inductor will produce an alternating magnetic field around the frequency of the same, so the workpiece will produce the same frequency of the induction current, the current in the workpiece to form a circuit, known as eddy current. This eddy current can make the electric energy into heat energy to heat the workpiece. The distribution of eddy currents in the workpiece is not uniform, the surface density is large, and the heart of the density is small. The higher the frequency of the current into the inductor, the eddy current concentration of the surface layer of the thinner, this phenomenon is called the skin effect. Because of the skin effect so that the surface of the workpiece is rapidly heated, applied in forging penetration on the heating frequency needs to be based on the size of the billet to determine, generally for the medium frequency, so that the surface and the heart of the temperature difference is not too large.
The main components of heating equipment
Induction heating equipment in forging production is mostly composed of the following parts:
(1). Power supply
Frequency range 500HZ-35KHZ, including intermediate frequency, ultra-audio. High-frequency, according to the size of the workpiece to choose the appropriate frequency, the power range of 15-1000KW IGBT power supply can be selected!
(2). Induction Heating Furnace
An induction heating furnace is mainly composed of induction coils wound with copper tubes and sealed high-temperature-resistant structure, the role of which is to convert electrical energy into heat to warm the billet (customized according to customer requirements).
(3). Controls and operating systems
The control and operating system in forging production is mostly based on PLC plus operation panel to execute the production beat. Intelligent and automated control to ensure high production accuracy and efficiency, commonly used accessories are shown below:
In this rapid development of industrialization, high productivity, and high-quality products is the common goal of all production-oriented enterprises. Time means efficiency, quality determines how far can go, and induction heating with its unique advantages in the heat treatment processing industry is widely used. With the development of more intelligent, miniaturized heating power supply, in each heat treatment industry has great significance, such as forging, welding, quenching, annealing, etc., with the corresponding mechanical devices, can completely realize automated production. With the emergence of new technologies, I believe the future of induction heating will also go further.
