Induction Heaters are getting popular in the manufacturing industry due to their efficiency, low environmental impact, and ease of use. An induction heater can safely perform multiple metalworking processes, such as melting, brazing, and annealing.
An induction heater is a device that uses an alternating current to create a magnetic field. The changing magnetic field induces eddy currents in the conductive material, heating it as per the Joule heating law.
The induction heating process has transformed multiple manufacturing techniques and enhanced their progress. One of these mechanical processes is the forging process.
What is Forging?
Forging is a process of shaping metal using compressive forces. These forces are applied through a hammer, press, or die.
Forging is one of the oldest processes goldsmiths use to shape metal and form metallic objects of desired shape and size. The process imparts multiple mechanical properties such as strength, fatigue resistance, and impact resistance to the forged material.
Hot and Cold Forging
A piece of metal can be forged in two states; either it is hammered in its current form or pre-heated above its recrystallization temperature.
When the forging process is done at room temperature without heating the metal, then this process is termed cold forging. Whereas if the workpiece is heated up to its crystallization temperature, that’s hot forging.
Cold forging is used when dealing with relatively softer metals; it makes them hard and imparts strength. In comparison, hot forging is used for nearly any type of metal. It is more common in industries since it allows for more precise metal shaping.
Use of Induction Heater for Forging of Metals
As mentioned earlier, hot forging requires heating the metal. The conventional way to heat metals for forging is through a furnace that runs on combustible fuel such as gas. It is a contact process, and multiple fumes are emitted due to fuel burning.
The best alternative to furnace heating is induction heating. For a small-scale application, like knife making, you can use an induction heater, and for large-scale applications, you can employ an induction furnace. You will need an electric supply to heat the metal in both cases.
Main Steps Involved in Forging Metals By Induction Heating
Here’s a list of three main steps involved in the induction forging of metals.
- Pre-heating with an Induction Heater: The first step is heating the workpiece (ingots) to the forging temperature with an induction heater. The ingot is heated to a temperature whose shape remains intact but can be changed by force.
- Hammering: Once the ingot is heated to the forging temperature, it is placed on the anvil. The anvil is a flat surface that is used to shape the metal. The metal is then hammered and changed into the desired shape. This process can be done by hand or with a press.
- Quenching: After the metal has been forged into the desired shape, it is cooled. This is done by quenching or by air cooling. Quenching is a process of cooling the metal quickly in water or oil. This helps harden the metal and prevents it from being damaged during cooling. Air cooling is a slower process but does not harden the metal.
Equipment Used for Induction Forging
Multiple induction forging machines are available on the market based on the size and application you need. At FOCO, we design two induction heaters for forging: one system for induction heating of steel, iron, and Aluminum bars. And the second system for heating billets.
Some key specification of each machine is stated below:
FOCO’s Induction Bar Heating System
- Used for Induction Forging of Metallic Bars
- Estimated Power Required: 25kW to 250kW
- Available as Automated and Semi-Automated System
FOCO’s Induction Billet Heating System
- Used for induction forging of square and round bills
- Estimated Power Required: 160kW to 3000kW
- The heating time is adjustable, and a temperature of 1100 C can be achieved.
- Available as Automated and Semi-Automated System
Advantages of Induction Heaters for Forging Applications
In comparison to conventional heaters, induction heaters do have multiple advantages. Some of the most notable ones include:
- Induction heaters have fast heating cycles; they can heat metal very quickly.
- They are safe to use and do not produce fumes or smoke.
- Induction heaters heat metal evenly, which helps to reduce the amount of time needed to forge the metal.
- They give a highly controllable environment compared to traditional gas furnaces.
- The production process can easily be automated if an induction heater is employed.
What metals can be forged through induction heating?
Almost all types of metals can be forged using induction heaters. However, the efficiency of heating differs in each case. Some of the most common metals forged with induction heaters include aluminum, brass, copper, iron, stainless steel, and titanium.
Heating metals through furnace vs. induction heating. Which process is better?
Previously gas furnaces were used for the pre-heating of metals. In that case, the furnace needs to be set up, and then it has to keep running for longer. You cannot stop it and then start again. The setup time is huge. At the same time, induction heaters supply heat on demand. They are controllable, and you can start and stop them without any delays. Moreover, the production time is short in the second case.
What are some limitations of induction forging?
Despite multiple advantages, using an induction heater for forging applications has some limitations. First, the metal that can be forged is limited by the size of the induction heater. Second, they are expensive. Third, they require a considerable setup cost and a high-frequency power source, which may be a constraint for some manufacturers.
Induction heaters are a very efficient way to heat metal for hot forging applications. They can heat the metal quickly and evenly, which helps to reduce the amount of time needed to forge the metal. Moreover, they are safe to use since they do not produce fumes contaminating the environment.
So, an induction heater is a perfect solution if you are looking for an efficient and safe way to heat metal for hot forging applications. You can also check out FOCO’s induction forging systems.