Induction rod heater

Introduce:used for bar, round steel, square steel, steel plate heating, temperature compensation, metal material online heating, providing induction rod heater selection method, induction rod heater furnace structure selection, induction rod heater power supply Calculation method, the method of selecting the efficiency of the induction rod heater. 
  • Introduction
  • Consultation

The complete set of automatic induction rod heater consists of: intermediate frequency power supply, capacitor cabinet, sensor, automatic feeding rack, unloading rack and control cabinet. The intermediate frequency power supply adopts a split structure design, and the power cabinet is a GGD standard cabinet. The capacitive cabinet and inductor are compact in design and increase heating efficiency.

Reasonable control of the distance between the sensor and the heating bar reduces the time for the red hot bar to be exposed to the air, reduces the scale of the bar, and reduces energy consumption. The speed of the transmission mechanism is automatically controlled according to the process parameters set by the user. When there is no workpiece in the sensor, the automatic control system automatically reduces the output power of the intermediate frequency power supply; the workpiece enters the sensor, and the automatic control system automatically increases the output power of the intermediate frequency power supply.

Induction rod heater technical parameters summary

Bar diameter

Bar length

Heating temperature

Furnace power

Φ16mm

300mm

1100

250kw/4000HZ

Φ31-80mm

70-480mm

1250

500kw/2500HZ

Φ120mm

1500mm

1250

2000kw/1000HZ

The medium frequency induction heating furnace can be customized according to actual needs.

timg (15).jpg

Induction rod heater application areas:

Forging heating: used for bar, round steel, square steel, steel plate heating, temperature compensation, blue quenching material online heating, local heating, metal material online forging (such as gears, semi-axle links, bearings, etc.) Extrusion, hot rolling, heating before shearing, spray heating, thermal assembly, and heating, annealing, tempering, etc. of the entire metal material.

Heat treatment: mainly for shafts (straight shaft, variable diameter shaft, camshaft, crankshaft, gear shaft, etc.); gears; sleeves, rings, discs; machine tool screws; guide rails; planes; ball heads; hardware tools, etc. Surface heat treatment of mechanical (automobile, motorcycle) parts and heating, annealing, tempering, etc. of the entire metal material.

What parameters are required for induction rod heater selection?

The selection of induction rod heaters generally requires the following parameters:

First: the shape of the heated workpiece, the outer dimensions, and the weight of the heated workpiece.

Second: the material material of the heated workpiece (generally induction heating, only for metal conductor materials).

Third: the time of the target temperature required for heating the heated workpiece, and the target temperature.

Once the above three points are clear, the induction rod heater can be selected to include matching power. 

What are the characteristics of the induction rod heater body structure?

1. Furnace structure: Our company's heating furnace is designed as an overall quick change type. Quick change is possible when changing the furnace body for different heated workpieces.

2. Furnace lining: The lining is made of silicon carbide or integral knotting, and the temperature is above 1450 °C.

3. Protection: Automatic shutdown when the water temperature exceeds 65 °C.

4. Induction furnace water cooling rail: Water-cooled rail is installed on the induction furnace lining.

How to calculate the power of the induction rod heater?

P=(0.168×200×693)/(0.24×0.6×145)=1029KW In the formula: 0.168—the average specific heat of the ferrous metal; 2080—the mass of the workpiece (Kg); 200—the temperature rise of the workpiece heating; 0.24— Work heat equivalent; 0.6 - average efficiency (0.6 in this case, generally 0.5 ~ 0.65, lower profile sensor, take 0.4); 145 - work beat (seconds)

According to the above calculation, a 1KHz induction heating device with a rated power of 1500 KW can be configured to meet the needs.

How to choose the power frequency of the induction rod heater?

The choice of power frequency follows the principle of optimal heating efficiency and temperature uniformity (core temperature difference). The higher the frequency, the higher the heating efficiency, but the too high frequency is likely to cause the surface of the workpiece to be too burnt. According to our experience, the frequency is selected to be 2500KHZ. , the best heating effect can be obtained without overheating the workpiece temperature.

How to choose and use the induction rod heater? Mainly from several aspects:

1. Shape and size of the heated workpiece

For large workpieces, bar stocks and solid materials, induction rod heaters with relatively high power and low frequency should be used. For small workpieces, pipes, plates, gears, etc., the induction rod heater with low relative power and high frequency should be used.

2. Depth and area required for heating

Deep heating depth, large area, overall heating, should use high power, low frequency induction rod heater; shallow heating depth, small area, local heating, the use of relatively low power, high frequency induction rod heater.

3, the required heating rate

The heating speed required is fast, and the induction rod heater with relatively large power and relatively high frequency should be selected.

4, the continuous working time of the equipment

The continuous working time is long, and the induction rod heater with a slightly larger power is used.

5, the connection distance between the sensing component and the device

The connection length is long, and even the use of water-cooled cable connection is required. The medium-frequency induction heating furnace with higher power should be used relatively.

6, process requirements

In general, quenching, welding and other processes, relatively power can be selected smaller, frequency selection is higher; annealing, tempering and other processes, relative power selection is larger, frequency selection is lower; red punch, hot calcination, smelting, etc., need For a heating process, the power should be chosen to be larger and the frequency selected lower.

7, the material of the workpiece

The relative power of the high melting point of the metal material is larger, the relative power of the lower melting point is smaller, the power of the smaller resistivity is larger, and the power of the larger resistivity is smaller. 

Significant advantages of the induction rod heater:

1. Compared with traditional heating means (oil, coal, gas), it has the remarkable advantages of environmental protection, energy saving, convenient operation and low labor intensity;

2. Compared with the thyristor intermediate frequency, the energy saving is 10%~30%, and there is no harmonic interference to the power grid;

3. Compared with the resistance furnace, the energy saving is 50%~60%;

4. It has the advantages of fast heating, uniform heating, no oxide layer and good product quality for customers' products;

5. The sensor is isolated by a transformer and is very safe.

6. Environmental protection: no pollution, noise and dust.

7. Adaptability: It can heat various workpieces with different shapes.

8, the equipment occupies a small area, less than two square meters, to facilitate customers to maximize the use of production space. 

Why is the induction rod heater efficient?

The principle of the induction rod heater is electromagnetic induction, and the heat is generated in the workpiece itself. The ordinary worker can carry out the continuous work of forging task ten minutes after going to work with the induction rod heater. The professional workers do not need to burn the furnace and seal the furnace in advance. Work. Don't worry about the waste of the heated billet caused

 by power failure or equipment failure. Because of the rapid heating rate of this

 heating method, there is very little oxidation, and at least 20-50 kg of steel raw

 materials are saved per ton of forgings compared with coal-fired furnaces. The

 material utilization rate can reach 95%. Because the heating method is evenly

heated,

the temperature difference of the core surface is extremely small, so the forging

die life is greatly increased in the forging, and the surface roughness of the forging

piece is also less than 50 um. The heat is heated inductively. It is produced in

the workpiece itself, so the heating is uniform, and the temperature difference

between the core and the core is very small. The temperature control system can

 realize the precise control of the temperature to improve the product quality and

 the pass rate.

 


Understand Wikipedia: induction heating
Recommended Reading: Induction heating furnace
Recommended Reading: bar induction heating furnace
Related Articles
Related Video