handbook of induction heating eddy current

PDF handbook of induction heating eddy current

Both induction heating and eddy current testing work with coils, generators, ac-current and ac-voltage, frequencies, field strength and induction law. Contrary to heating of the test parts, the eddy current test does not want to heat the parts at all but wants to examine them for their metallurgical microstructure, thus for their mechanical features like hardness, case depth or alloy. The eddy current test does not provide absolute values (e.g. "56 HRC" or "2.6 mm case depth"). The eddy current test does detect fine differences in micro-structure with high sensitivity. In the production line, within a fraction of a second, a non-destructive 100 % test for • hardness • case depth • hardness run out, hardness pattern • tensile strength • carbon content • soft spots • surface decarburisation is completed, and thus quick corrective reactions to any variance from the specified structure can be realized. With a suitable mechanical part handling arrangement, the transport from the hardening station to the test station takes only a few seconds. Faulty parts, caused by a damaged inductor, a jammed quench nozzle or an unknown reason are immediately detected, providing an enormous savings in time and costs! [caption id="attachment_7309" align="alignright" width="1024"] induction-heating-eddy-current.[/caption] Different from the induction heating, the energy for eddy current testing is very small, in the milliwatt range. Field strength is low and permeability is in the range of the initial permeability. Test frequencies ranging from some Hz to some hundreds of kHz provide information on undesired structures via the frequency dependent penetration depth of the eddy current and on the formation of permeability. Very small electrical signals require a very precise evaluation in order to assure their differentiation from ambient interferences. A small drift from variation in temperature and high long term stability are absolutely necessary. Digitization of input voltages immediately at the front end of the electronic evaluation is of huge advantage. Handbook-Induction-Heating-Eddy-Current-Paper-EN

Brazing Carbide Tips To Steel With Induction

Brazing Carbide Tips To Steel With Induction Heater Objective: Braze a carbide tip to a 4140 steel cutting tool Material: Carbide Isograde C2 & C5 tips, 4140 circular steel cutter, flux and silver braze shim Temperature 1400 ºF (760 ºC) Frequency 250 kHz Equipment • DW-UHF-20 kW induction heating system, equipped with a remote workhead containing two 1.5μF capacitors for a total of 0.75μF • An induction heating coil designed and developed specifically for this application. Process A split helical coil is used to heat the carbide & circular steel cutter evenly for the brazing application. The circular steel cutter is placed in a vise and the carbide and braze shim are placed onto the tooth. The assembly is heated for 5 seconds to braze the carbide to the circular steel cutter. The circular steel cutter is rotated in the vise & each carbide tip is brazed separately without effecting the previous braze. Results/Benefits Induction heating provides: • Rapid, localized heat applied only to tip being brazed, will not effect previous brazes on the assembly • Neat and clean joints • Produces high quality repeatable parts

Tube and Pipe Seam Welding Machine With Induction Heater

Induction Seam Welding Machine For Welding Tube and Pipe Solutions

What is induction welding? With induction welding, the heat is electromagnetically induced in the workpiece. The speed and accuracy of induction welding makes 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 advantages of induction Seam welding? Automated induction longitudinal welding is a reliable, high-throughput process. The low power consumption and high efficiency of HLQ 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 footprint make them easy to integrate or retrofit into production lines. Where is induction seam welding 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 high-strength low-alloy (HSLA) steels and many other conductive materials. High Frequency Induction Seam Welder In the high frequency induction tube welding process, high frequency current is induced in the open seam tube by an induction coil located ahead of (upstream from) the weld point, as shown in Fig. 1-1. The tube edges are spaced apart when they go through the coil, forming an open vee whose apex is slightly ahead of the weld point. The coil does not contact the tube. Fig 1-1 The coil acts as the primary of a high frequency transformer, and the open seam tube acts as a one-turn secondary. As in general induction heating applications, the induced current path in the work piece tends to conform to the shape of the induction coil. Most of the induced current completes its path around the formed strip by flowing along the edges and crowding around the apex of the vee-shaped opening in the strip. The high frequency current density is highest in the edges near the apex and at the apex itself. Rapid heating takes place, causing the edges to be at welding temperature when they arrive at the apex. Pressure rolls force the heated edges together, completing the weld. It is the high frequency of the welding current that is responsible for the concentrated heating along the vee edges. It has another advantage, namely that only a very small portion of the total current finds its’ way around the back of the formed strip. Unless the diameter of the tube is very small compared with the vee length, the current prefers the useful path along the edges of the tube forming the vee. Product: Induction Seam Welding Machine 

All Solid State (MOSFET) High Frequency Induction Seam Welding Machine For Tube and Pipe
Model	GPWP-60	GPWP-100	GPWP-150	GPWP-200	GPWP-250	GPWP-300
Input power	60KW	100KW	150KW	200KW	250KW	300KW
Input voltage	3Phases,380/400/480V
DC Voltage	0-250V
DC Current	0-300A	0-500A	800A	1000A	1250A	1500A
Frequency	200-500KHz
Output efficiency	85%-95%
Power factor	Full load＞0.88
Cooling Water Pressure	>0.3MPa
Cooling Water Flow	>60L/min	>83L/min	>114L/min	>114L/min	>160L/min	>160L/min
Inlet water temperature	<35°C

Technical Features:  True all-solid-state IGBT power adjustment and variable current control technology, using unique IGBT soft-switching high-frequency chopping and amorphous filtering for power regulation, high-speed and precise soft-switching IGBT inverter control, to achieve 100-800KHZ/3 -300KW product application.

1. Imported high-power resonant capacitors are used to obtain stable resonant frequency, effectively improve product quality, and realize the stability of the welded pipe process.
2. Replace the traditional thyristor power adjustment technology with high-frequency chopping power adjustment technology to achieve microsecond level control, greatly realize the rapid adjustment and stability of the power output of the welding pipe process, the output ripple is extremely small, and the oscillation current is stable. The smoothness and straightness of the weld seam are guaranteed.
3. Security. There is no high frequency and high voltage of 10,000 volts in the equipment, which can effectively avoid radiation, interference, discharge, ignition and other phenomena.
4. It has a strong ability to resist network voltage fluctuations.
5. It has a high power factor in the whole power range, which can effectively save energy.
6. High efficiency and energy saving. The equipment adopts high-power soft switching technology from input to output, which minimizes power loss and obtains extremely high electrical efficiency, and has extremely high power factor in the full power range, effectively saving energy, which is different from traditional Compared with the tube type high frequency, it can save 30-40% of the energy saving effect.
7. The equipment is miniaturized and integrated, which greatly saves the occupied space. The equipment does not need a step-down transformer, and does not need a power frequency large inductance for SCR adjustment. The small integrated structure brings convenience in installation, maintenance, transportation, and adjustment.
8. The frequency range of 200-500KHZ realizes the welding of steel and stainless steel pipes.

HLQ Induction has the most comprehensive range of solutions for the tube and pipe industry. HLQ Induction Seam Welder is a proven solution for welding stainless steel, aluminum, low-carbon steel and high-strength steel and is possibly the world's best induction welder. More output: Continuous electronic load matching secures full power output across a wide range of tube sizes. More uptime: Short-circuit-proof, safe and reliable operation. Unrivalled efficiency: Diode rectifier with a constant power factor of 0.95 at all power levels, and an efficiency factor of 85-87%. Eco and energy friendly: High efficiency saves energy and reduces cooling water consumption. Easy to operate: An easy-to-use control panel with a minimum of manual settings makes the Induction Seam Welder extremely easy to operate. Wide range of power sizes: From 40 kW up to 1000 kW. A frequency range of 200-500 kHz.Modern modular design: The small, compact footprint saves valuable floor-space and simplifies in-line integration. Up to 1000 kW available in a one-cabinet solution. Complete system: Consisting of a diode rectifier, ­inverter modules, output section, busbar and operator control system. Unmatched warranty: three-year warranty on HLQ Induction Seam Welder inverter modules and driver cards. Full range of consumables:  Coils, ferrite, impeders and tube scarfing equipment.

Induction Brazing Carbide To Steel

Objective Induction Brazing carbide to steel parts Equipment DW-HF-15kw Induction Heating Power Supply HLQ custom coil Key Parameters Power: 5.88 kW Temperature: Approximately 1500°F (815°C) Time: 10 sec Materials Coil-  2 helical turns (20 mm ID) 1 planar turn (40 mm OD, 13 mm Height) Carbide-  13 mm OD, 3 mm wall thickness Steel piece– 20 mm OD, 13 mm ID

Process:

1. To demonstrate elimination of “hand feeding” the alloy, we formed the alloy into a ring to tightly fit over the center post tube. This method provides a uniform amount for each cycle, resulting in uniform joints and wetting.
2. The custom made coil was then placed over the steel piece, where is was set for 10 seconds to heat the alloy.
3. The alloy was heated at approximately 1500°F (815)°C
4.  The whole piece is left alone and cooled with ambient air

Results/Benefits:

• Induction Brazing was successful all in under 15 seconds with 8kW
• High quality and repeatability of the brazed joints
• Increased productivity
• Rings will need to be developed for specific joints to prevent the use of too much alloy
• Precise control of the time and temperature

portable ultrasonic mask welding machine for welding medical mask KN95 earloop

Portable ultrasonic mask welding machine-portable mask ultrasonic welder for bonding KN95 face earloop and nonwoven fabric and mask.

800W 28KHz portable mask portable ultrasonic mask welding machine for KN95& Mask Ear Loop Spot Welding ,Ultrasonic Face Mask Welding Machine Manually Used Device With Welding Head Transducer Generator.

Face Mask Ultrasonic Welding Machine

For N95 Face Mask & Disposable Mask

Transducer Frequency: 28KHz

Transducer Material: Magnalium

Welding Head Material:Titanium Alloy

Working Voltage: AC220V±10%(50-60HZ)

Working Frequency: 28KHz

Working Power: 800W

Whole set includes:

1) 28KHz Ultrasonic generator

2) Plastic body

3) 28KHz Ultrasonic transducer

4) Welding head

 

   

  

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Induction Soldering Brass Connector

Induction Soldering Brass Connector In Solar Panel With IGBT Induction Heater Objective Solder three brass connectors one at a time in a solar panel junction box without affecting the components in the junction box Material Solar panel junction box, brass connectors, solder wire Temperature 700 ºF (371 ºC) Frequency 344 kHz Equipment • DW-UHF-6 kW induction heating system, equipped with a remote workhead containing one 1.0 μF capacitor. • An induction heating coil designed and developed specifically for this application. Process A three turn oval shaped helical coil is used to heat the connectors. A piece of solder wire is placed onto the joint area and each joint is heated separately for 5 seconds to solder the connector. The total process time is 15 seconds for the three joints. Results/Benefits Induction heating provides: • Pinpoint accuracy deliver heating only to joint; does not affect surrounding components • Localized heat produces neat and clean joints • Produces high quality, repeatable results • Even distribution of heating                            

how does induction heating work?

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. [pdf-embedder url="https://dw-inductionheater.com/wp-content/uploads/2018/08/induction_heating_principle-1.pdf" title="induction_heating_principle"]