• induction heating principle

A source of high frequency electricity is used to drive a large alternating current through a induction coil. This induction heating coil is known as the work coil. See the picture opposite.
The passage of current through this induction heating coil generates a very intense and rapidly changing magnetic field in the space within the work coil. The workpiece to be heated is placed within this intense alternating magnetic field.
Depending on the nature of the workpiece material, a number of things happen…
The alternating magnetic field induces a current flow in the conductive workpiece. The arrangement of the work coil and the workpiece can be thought of as an electrical transformer. The work coil is like the primary where electrical energy is fed in, and the workpiece is like a single turn secondary that is short-circuited. This causes tremendous currents to flow through the workpiece. These are known as eddy currents.
In addition to this, the high frequency used in Induction Heating applications gives rise to a phenomenon called skin effect. This skin effect forces the alternating current to flow in a thin layer towards the surface of the workpiece. The skin effect increases the effective resistance of the metal to the passage of the large current. Therefore it greatly increases the induction heating effect of the induction heater caused by the current induced in the workpiece.

induction_heating_principle
  • Induction Curing Heating of Organic Coating

Induction Curing Heating of Organic Coating

Induction Heating is used to cure organic coating such as paint on metallic substrates by generating heat with in the subtract .By this mean curing occurs from within minimizing the tendency for formation of coating defects . A typical is application is drying of paint on sheet metal.
Induction heating of metal parts to adhesive induction curing temperatures is utilized in a many automotive processes, such as the use of thermosetting adhesives to produce clutch plates, brake shoes and auto bumper components. Shafts are typically bonded to the squirrel cage rotors in the manufacture of small motors. In copying machines, plastic components are adhesively bonded to aluminum rotors; a thermoplastic glue is used to hold foam rollers on metal shafts. Once the rollers wear out, the shaft is heated and the foam replaced.
Modern induction heating can solve many of these problems. Heating with induction provides reliable, repeatable, non-contact and energy-efficient heat in a minimal amount of time, so that the curing process can be completed with minimal energy and time. Improved temperature ramping cycles can be achieved with computer control of the solid state power supply. To eliminate extra steps for loading and unloading ovens, induction heat stations can be incorporated into a production line. Finally, induction heating can be performed in extremely clean environments, vacuum conditions or special atmospheres, allowing for unique curing solutions.

Although induction heating is normally used with metals or other conductive materials, plastics and other non-conductive materials can often be heated very effectively by using a conductive metal susceptor to transfer the heat. Typical RF power supplies for induction curing applications range from 4 to 60kW, depending on the parts and application requirements.

  • induction preheating copper rod

Induction preheating copper rod for hot forging

In order to want to improve safety and productivity, and reduce energy costs, by using induction instead of resistive heating. To maximize productivity, they want to be able to heat 3 brass rods at a time to 780° C within 25 seconds. For this application test, we are only heating one rod, so our goal is to heat the single rod to 780° C within 25 seconds with less than 45 kW of power. This will ensure that when heating 3 rods, that the 110 kW system will meet the production requirements.

Equipment
DW-HF-70kW Induction Heating Power Supply, operating between 10-50 kHz

Materials
• Brass rod
• Custom coil, 10 turns, D=50mm, designed and manufactured by DaWei Induction Power Technologies for this specific application – capable to heat 3 rods at a heat cycle.

Key Parameters
Temperature: 780° C
Power: 70 kW
Voltage: 380 – 480 V
Time: 24 sec
Frequency: 32 kHz

Process:

  1. The DW-HF series Power Supply was connected to the DW-HF-70kw Heat Station.
  2. The custom Coil was attached to the Heat Station.
  3. The Brass rods were placed inside the Coil.
  4. The Power Supply was turned on.
  5. The DW-HF series operating at 20 kW was able to successfully heat the single brass rod within 24 seconds, which was less than the 25 second time requirement established for the test. Three brass rods are expected then to heat within 25 seconds with approximately 60 kW of power (3 rods will be 3x the load and 3x the power). The 90 kW Induction system will therefore meet the customer’s requirements.

Results/Benefits:

Induction preheating provides:

  • Faster heating cycles
  • The process is safer than the flame heating
  • Technology without pollution, clean and safe

 

  • induction heating principle

A source of high frequency electricity is used to drive a large alternating current through a induction coil. This induction heating coil is known as the work coil. See the picture opposite.
The passage of current through this induction heating coil generates a very intense and rapidly changing magnetic field in the space within the work coil. The workpiece to be heated is placed within this intense alternating magnetic field.
Depending on the nature of the workpiece material, a number of things happen…
The alternating magnetic field induces a current flow in the conductive workpiece. The arrangement of the work coil and the workpiece can be thought of as an electrical transformer. The work coil is like the primary where electrical energy is fed in, and the workpiece is like a single turn secondary that is short-circuited. This causes tremendous currents to flow through the workpiece. These are known as eddy currents.
In addition to this, the high frequency used in Induction Heating applications gives rise to a phenomenon called skin effect. This skin effect forces the alternating current to flow in a thin layer towards the surface of the workpiece. The skin effect increases the effective resistance of the metal to the passage of the large current. Therefore it greatly increases the induction heating effect of the induction heater caused by the current induced in the workpiece.

induction_heating_principle

Magnetic Induction Heater  is a process equipment which is used to melt,braze,forge,bond,heat treating,harden or soften metals or other conductive materials. For many modern manufacturing processes, Magnetic induction heating equipment offers an attractive combination of speed, consistency and control.The basic principles of magnetic induction heating have been understood and applied to manufacturing since the 1920s. During World War II, the technology developed rapidly to meet urgent wartime requirements for a fast, reliable process to harden metal engine parts. More recently, the focus on lean manufacturing techniques and emphasis on improved quality control have led to a rediscovery of induction technology, along with the development of precisely controlled, all solid state induction power supplies.

Magnetic Induction Heater relies on the unique characteristics of induction heating radio frequency (RF) energy – that portion of the electromagnetic spectrum below infrared and microwave energy. Since heat is transferred to the product via electromagnetic waves, the part never comes into direct contact with any flame, the inductor itself does not get hot, and there is no product contamination. When properly set up, the process becomes very repeatable and controllable.

Main Characteristics:
   1.IGBT module and soft switiching inverting technologies are as in the production of the generator,higher reliability can be do. 
   2. Small and portable ,compared with SCR controlled machine only 1/10 working space is needed.
3.  High efficiency to save energy,high efficiency and power far can be maintained
   4.  The generator is adatable in a large frequency range from 1KHZ to 1100KHZ,installation can be done very easily according to our manual.  
     5. 100%duty cycle ,continuous working ability at maximum power.  
     6. Constant power or constant voltage control mode.
     7. Display of output power,output frequency,and output voltage.
Series
Model
Input power Max
Input current Max
Oscillate frequency
Input Voltage
Duty cycle
M
.
F
.
DW-MF-15 Induction Generator
15KW
23A
1K-20KHZ
According to the application
3*380V
380V±20%
100%
DW-MF-25 Induction Generator
25KW
36A
DW-MF-35Induction Generator
35KW
51A
DW-MF-45 Induction Generator
45KW
68A
DW-MF-70 Induction Generator
70KW
105A
DW-MF-90 Induction Generator
90KW
135A
DW-MF-110 Induction Generator
110KW
170A
DW-MF-160 Induction Generator
160KW
240A
DW-MF-45 Induction Heating Rod Forging Furnace
45KW
68A
1K-20KHZ
3*380V
380V±20%
100%
DW-MF-70 Induction Heating Rod Forging Furnace
70KW
105A
DW-MF-90 Induction Heating Rod Forging Furnace
90KW
135A
DW-MF-110 Induction Heating Rod Forging Furnace
110KW
170A
DW-MF-160 Induction Heating Rod Forging Furnace
160KW
240A
DW-MF-15   Induction Melting Furnace
15KW
23A
1K-20KHZ
3*380V
380V±20%
100%
DW-MF-25   Induction Melting Furnace
25KW
36A
DW-MF-35   Induction Melting Furnace
35KW
51A
DW-MF-45   Induction Melting Furnace
45KW
68A
DW-MF-70   Induction Melting Furnace
70KW
105A
DW-MF-90   Induction Melting Furnace
90KW
135A
DW-MF-110 Induction Melting Furnace
110KW
170A
DW-MF-160 Induction Melting Furnace
160KW
240A
DW-MF-110 Induction Hardening Equipment
110KW
170A
1K-8KHZ
3*380V
380V±20%
100%
DW-MF-160Induction Hardening Equipment
160KW
240A
H
.
F
.
DW-HF-04 Series
DW-HF-4KW-A
4KVA
15A
100-250KHZ
Single phase 220V
80%
DW-HF-15 Series
DW-HF-15KW-A
DW-HF-15KW-B
15KVA
32A
30-100KHZ
Single phase 220V
80%
DW-HF-25 Series
DW-HF-25KW-A
DW-HF-25KW-B
25KVA
23A
20-80KHZ
3*380V
380V±20%
100%
DW-HF-35 Series
DW-HF-35KW-B
35KVA
51A
DW-HF-45 Series
DW-HF-45KW-B
45KVA
68A
DW-HF-60 Series
DW-HF-60KW-B
60KVA
105A
DW-HF-80 Series
DW-HF-80KW-B
80KVA
130A
DW-HF-90 Series
DW-HF-90KW-B
90KVA
160A
DW-HF-120 Series
DW-HF-120KW-B
120KVA
200A
U
.
H
.
F
.
DW-UHF-3.2KW
3.2KW
13A
1.1-2.0MHZ
Single phase220V
±10%
100%
DW-UHF-4.5KW
4.5KW
20A
DW-UHF-045T
4.5KW
20A
DW-UHF-045L
4.5KW
20A
DW-UHF-6KW-I
6.0KW
28A
DW-UHF-6KW-II
6.0KW
28A
DW-UHF-6KW-III
6.0KW
28A
DW-UHF-10KW
10KW
15A
100-500KHZ
3*380V
380V±10%
100%
DW-UHF-20KW
20KW
30A
50-250KHZ
DW-UHF-30KW
30KW
45A
50-200KHZ
DW-UHF-40KW
40KW
60A
50-200KHZ
DW-UHF-6, 0KW
60KW
90A
50-150KHZ

Induction_heating_catalogue.pdf

Induction Brazing Machine&Soldering Equipment
Main characteristics:
    1.  IGBT module and inverting technologies of the first generation been used.
    2.  Simple structure and light weight and easy for maintenance.
    3.  Simple to operat ,afew minutes is enough to learn it.
    4.  Simple to install,installation can be done by unprofessional person very easily.
    5.  advantages of the model with timer,the power and the operatingtime of the heating period and the rain period  can be preset repectively,to realize a simple heating curve,this model is suggested to use for batch production to improve the repeatability.
   6.   The separated models are designed to fit the dirty surrounding of some cases.
Specifications
Series
Model
Input power Max
Input current Max
Oscillate frequency
Input Voltage
Duty cycle
M
.
F
.
DW-MF-15 Induction Generator
15KW
23A
1K-20KHZ
According to the application
3*380V
380V±20%
100%
DW-MF-25 Induction Generator
25KW
36A
DW-MF-35Induction Generator
35KW
51A
DW-MF-45 Induction Generator
45KW
68A
DW-MF-70 Induction Generator
70KW
105A
DW-MF-90 Induction Generator
90KW
135A
DW-MF-110 Induction Generator
110KW
170A
DW-MF-160 Induction Generator
160KW
240A
DW-MF-45 Induction Heating Rod Forging Furnace
45KW
68A
1K-20KHZ
3*380V
380V±20%
100%
DW-MF-70 Induction Heating Rod Forging Furnace
70KW
105A
DW-MF-90 Induction Heating Rod Forging Furnace
90KW
135A
DW-MF-110 Induction Heating Rod Forging Furnace
110KW
170A
DW-MF-160 Induction Heating Rod Forging Furnace
160KW
240A
DW-MF-15   Induction Melting Furnace
15KW
23A
1K-20KHZ
3*380V
380V±20%
100%
DW-MF-25   Induction Melting Furnace
25KW
36A
DW-MF-35   Induction Melting Furnace
35KW
51A
DW-MF-45   Induction Melting Furnace
45KW
68A
DW-MF-70   Induction Melting Furnace
70KW
105A
DW-MF-90   Induction Melting Furnace
90KW
135A
DW-MF-110 Induction Melting Furnace
110KW
170A
DW-MF-160 Induction Melting Furnace
160KW
240A
DW-MF-110 Induction Hardening Equipment
110KW
170A
1K-8KHZ
3*380V
380V±20%
100%
DW-MF-160Induction Hardening Equipment
160KW
240A
H
.
F
.
DW-HF-04 Series
DW-HF-4KW-A
4KVA
15A
100-250KHZ
Single phase 220V
80%
DW-HF-15 Series
DW-HF-15KW-A
DW-HF-15KW-B
15KVA
32A
30-100KHZ
Single phase 220V
80%
DW-HF-25 Series
DW-HF-25KW-A
DW-HF-25KW-B
25KVA
23A
20-80KHZ
3*380V
380V±10%
100%
DW-HF-35 Series
DW-HF-35KW-B
35KVA
51A
DW-HF-45 Series
DW-HF-45KW-B
45KVA
68A
DW-HF-60 Series
DW-HF-60KW-B
60KVA
105A
DW-HF-80 Series
DW-HF-80KW-B
80KVA
130A
DW-HF-90 Series
DW-HF-90KW-B
90KVA
160A
DW-HF-120 Series
DW-HF-120KW-B
120KVA
200A
U
.
H
.
F
.
DW-UHF-3.2KW
3.2KW
13A
1.1-2.0MHZ
Single phase220V
±10%
100%
DW-UHF-4.5KW
4.5KW
20A
DW-UHF-045T
4.5KW
20A
DW-UHF-045L
4.5KW
20A
DW-UHF-6.0KW
6.0KW
28A
DW-UHF-06A
6.0KW
28A
DW-UHF-6KW-B
6.0KW
28A
DW-UHF-10KW
10KW
15A
100-500KHZ
3*380V
380V±10%
100%
DW-UHF-20KW
20KW
30A
50-250KHZ
DW-UHF-30KW
30KW
45A
50-200KHZ
DW-UHF-40KW
40KW
60A
50-200KHZ
DW-UHF-60KW
60KW
90A
50-150KHZ

 

Portable Post Weld Heating Treatment System With Induction 

Main Application:

l  Preheat: weld heat,coating, spraying, bending, fitting&unfitting heat

l  Post-weld heat treatment: tank, boile, pipeline, steel sheet or other metal jobs

l  InductionHeat: mold heating, shipboard, zinc bath, large& irregular metal parts

l  Pipeline material heat: pipeline oil, pipeline gas, pipeline water, pipeline petrochemical and other pipeline material

Main Features

* High speed: 70%

*  Low tolerance

*  Energy Saving

*  High efficiency

*  Accurate heating

*  Simple operation

*  Non-contact heating

*  Environmental protection

*  Hypothermia circumstance

* Air cooling is suitable for low-temperature environment

* Induction heating is more uniform than oil,gas,flame heating portable post weld heating treatment system

MYD-20KWMYD-10KW
Input voltage3*380V, 50/60Hz, 4 Wires
Input Current1~30A1~15A
Output Current0~300A0~200A
Output Power1~20KW1~10KW, Max 15KW, 150% duty cycle
Output Frequency5~30KHZ
ThermocoupleK type
Temperature systemBuild in induction machine
Heating TemperatureMax800℃Max500℃
Size700 x 330 x 410 mm650 x 310 x 410 mm
Weight32kg26 kg
Induction Heating coil
Length10~20 M
Diameter15 mm
Working temperature-30~45℃
Pipeline SizeOD: 50~500mm or equivalent

Induction Brazing Basics for jointing copper,silver,brazing,steel and stainless steel,etc.

Induction Brazing uses heat and filler metal to join metals. Once melted, the filler flows between close-fitting base metals (the pieces being joined) by capillary action. The molten filler interacts with a thin layer of the base metal to form a strong, leak-proof joint. Different heat sources can be used for brazing: induction and resistance heaters, ovens, furnaces, torches, etc. There are three common brazing methods: capillary, notch and moulding. Induction brazing is concerned solely with the first of these. Having the correct gap between the base metals is crucial. A too-large gap can minimize the capillary force and lead to weak joints and porosity. Thermal expansion means gaps have to be calculated for metals at brazing, not room, temperatures. Optimum spacing is typically 0.05 mm – 0.1 mm. Before you braze Brazing is hassle-free. But some questions should be investigated — and answered — in order to assure successful, cost-effective joining. For instance: How suitable are the base metals for brazing; what’s the best coil design for specific time and quality demands; should the brazing be manual or automatic?

brazing material
At DAWEI Induction we answer these and other key points before suggesting a brazing solution. Focus on flux Base metals must usually be coated with a solvent known as flux before they are brazed. Flux cleans the base metals, prevents new oxidation, and wets the brazing area prior to brazing. It is crucial to apply sufficient flux; too little and the flux may become
saturated with oxides and lose its ability to protect the base metals. Flux is not always needed. Phosphorous-bearing filler
can be used to braze copper alloys, brass and bronze. Flux-free brazing is also possible with active atmospheres and vacuums, but the brazing must then be performed in a controlled atmosphere chamber. Flux must normally be removed from the part once the metal filler has solidified. Different removal methods are used, the most common being water quenching, pickling and wire brushing.

 

Why choose Induction Brazing?

Induction heating technology is steadily displacing open flames and ovens as the preferred heat source in brazing. Seven key reasons explain this growing popularity:

1. Speedier solution
Induction heating transfers more energy per square millimeter than an open flame. Put simply, induction can braze more parts per hour than alternative processes.
2. Quicker throughput
Induction is ideal for in-line integration. Batches of parts no longer have to be taken aside or sent out for brazing. Electronic controls and customized coils let us integrate the brazing process into seamless production processes.
3. Consistent performance
Induction heating is controllable and repeatable. Enter your desired process parameters into the induction equipment, and it will repeat heating cycles with only negligible deviations.

4. Unique controllability

Induction lets operators view the brazing process, something that is difficult with flames. This and precise heating minimize the risk of overheating, which causes weak joints.
5. More productive environment
Open flames create uncomfortable working environments. Operator morale and productivity suffer as a result. Induction is silent. And there is virtually no increase in ambient temperature.
6. Put your space to work
DAWEI Induction brazing equipment has a small footprint. Induction stations slot easily into production cells and existing layouts. And our compact, mobile systems let you work on hard-to-access parts.
7. No-contact process
Induction produces heat within the base metals — and nowhere else. It’s a no-contact process; the base metals never come into contact with flames. This protects the base metals from warping, which in turn increases yield and product quality.

why choose brazing induction

 

 

 
why choose induction brazing

 

What is induction annealing?
This process heats metals that have already undergone significant processing. Induction annealing reduces hardness, improves ductility and relieves internal stresses. Full-body annealing is a process where the complete workpiece is annealed. With seam annealing (more accurately known as seam normalizing), only the heat-affected zone produced by the welding process is treated.
What are the benefits?
Induction annealing and normalizing delivers fast, reliable and localized heat, precise temperature control, and easy in-line integration. Induction treats individual workpieces to exact specifications, with control systems continuously monitoring and recording the entire process.
Where is it used?
Induction annealing and normalizing is widely used in the tube and pipe industry. It also anneals wire, steel strips, knife blades and copper tubing. In fact, induction is ideal for virtually any annealing task.
What equipment is available?
Each DAWEI Induction annealing system is built to satisfy specific requirements. At the heart of each system is
an DAWEI Induction Heating generator that features automatic load matching and a constant power factor at all power levels. Most of our delivered systems also feature custom-built handling and control solutions.

induction annealing tube

What is induction welding?
With induction welding the heat is electromagnetically induced in the workpiece. The speed and accuracy
of induction welding make it ideal for edge welding of tubes and pipes. In this process, pipes pass an induction coil at high speed. As they do so, their edges are heated then squeezed together to form a longitudinal weld seam. Induction welding is particularly suitable for high-volume production. Induction welders can also be fitted with contact heads, turning them into
dual purpose welding systems.
What are the benefits?
Automated induction longitudinal welding is a reliable, high-throughput process. The low power consumption and high efficiency of DAWEI Induction welding systems reduce costs. Their controllability and repeatability minimize scrap. Our systems are also flexible—automatic load matching ensures full output power across a wide range of tube sizes. And their small footprints make them easy to integrate or retrofit into production lines.
Where is it used?
Induction welding is used in the tube and pipe industry for the longitudinal welding of stainless steel (magnetic and non-magnetic), aluminum, low-carbon and highstrength low-alloy (HSLA) steels and many other conductive
materials.
induction welding tubes