Induction Annealing Saw Blades

Objective: Induction Annealing saw blades used for cutting bread, prior to hole punching.

Material .38″ (9.6mm) wide and .51″ (12.9mm) wide continuous strips of 400 series stainless steel.

Temperature 600°C (315.6°F) for one second

Frequency 589kHz

Equipment • DW-UHF-6KW induction heating system equipped with a remote workhead containing one 1.00 μF capacitor. • An induction heating coil designed and developed specifically for this application.

Process A three turn helical coil at a 45º angle is used to anneal a 1.2″ (30.5mm) strip of saw blade prior to hole punching.

Results/Benefits Induction heating provides: • Improved quality of blades at hole punching location • Decreased scrap product • Easily incorporated into existing production lines

Induction Annealing Copper Wire

Objective: Induction Annealing a brazing copper wire for preform production.

Material: Copper Nickel Silver 2774 Alloy rod 0.070″ (1.8mm) diameter.

Temperature 650ºF(343.3ºC)

Frequency 580 kHz

Equipment: • DW-UHF-6kW-III induction heating system equipped with a remote workhead with one 1.0 μF capacitor, and a 4-20 mA input controller to aid in voltage ramping. • An induction heating coil designed and developed specifically for this application.

Process A unique helical coil consisting of four consecutive coils connected in parallel with a quartz tube lining is used to heat the wire to 650ºF (343.3ºC) for annealing.

Results/Benefits Induction heating provides: • Higher productivity of 27′ (8.2m) per minute • Reduction in surface oxidation & scaling • Consistent, repeatable results

High Frequency Induction Brazing Diamond Inserts

Objective: Induction Brazing diamond inserts to a steel drilling ring

Material : • steel ring and diamond inserts • Braze shim preform • Flux

Temperature :1300 – 1350 (700 – 730) °F (°C)

Frequency :78 kHz

Equipment: DW-HF-15kW, induction heating system, equipped with a remote heat station containing two 0.5 μF capacitors (total 0.25 μF) An induction heating coil designed and developed specifically for this application.

Process: A multi-turn, internal-external helical coil (A) is used to generate the required heating pattern. Initial tests on the ring alone determine system tuning. Flux is applied to the part and the braze shims are inserted into the counter-bored holes (B). This is followed by the synthetic diamonds. The part is loaded into the coil and weight is placed onto the diamonds (C). RF Induction Heating power is applied until the braze flows. The power is turned off and the part air cools to room temperature.

Results/Benefits • reduced ring warping compared to furnace induction heating • decreased cycle time due to reduced ramp-up and cooldown times

Induction Brazing Carbide File

Objective: Induction Brazing carbide rotary file assemblies with uniform concentricity in an aerospace application

Material • Carbide blank • High speed steel shank • Temperature indicating paint • Braze shim and black flux

Temperature 1400°F (760°C)

Frequency 550 kHz

Equipment: DW-UHF-4.5kw induction heating system, equipped with a remote heat station containing two 0.33 μF capacitors (total 0.66 μF) An induction heating coil designed and developed specifically for this application.

Process A multi-turn helical coil is used. The part is heated to determine the time required to reach the desired temperature and required heat pattern. It takes approximately 30 – 45 seconds to reach 1400°F (760°C) depending on the various part sizes. Flux is applied to the entire part. A braze shim is sandwiched between the steel shank and carbide. Induction heating power is applied until the braze flows. With proper fixturing, concentricity of the part can be achieved.

Results/Benefits • Repeatable, consistent precise heat.

 

Induction Brazing Copper Fittings
Objective: Copper ‘tees’ and ‘ells’ are to be brazed to the aluminum body of a refrigeration valve

Material: customer’s valve copper fittings braze

Temperature: 2550 ºF (1400°C)

Frequency: 585 kHz

Equipment: DW-UHF-10kw induction heating system including a workhead containing two 1.5μF capacitors (total 0.75μF) and a three-turn helical coil

Process: The valve is placed inside the coil and RF induction heating power is applied until the part is heated to the required temperature and the braze is seen to flow into the joint. Two tube sizes were run using the same induction heating system settings with differing cycle times.

Results/Benefits • energy is applied only to the zone to be heated • heating of the joint/braze is uniform and repeatable

What is induction hardening?

Induction hardening uses induced heat and rapid cooling (quenching) to increase the hardness and durability of steel.Induction heating is a no-contact process that quickly produces intense, localized and controllable heat. With induction, only the part to be hardened is heated. Optimizing process parameters such as heating cycles, frequencies and coil and quench design results in the best possible outcomes.

What are the benefits?

Induction hardening boosts throughput. It is an extremely fast and repeatable process that integrates easily into production lines. With induction it is usual to treat individual workpieces. This ensures each separate workpiece is hardened to its own precise specifications. The optimized process parameters for each workpiece can be stored on your servers. Induction hardening is clean, safe and typically has a small footprint. And because only the part of the component to be hardened is heated, it is extremely energy-efficient.

Where is it used?

Induction heating is used to harden numerous components. Here are just a few of them: gears, crankshafts, camshafts, drive shafts, output shafts, torsion bars, rocker arms, CV joints, tulips, valves, rock drills, slewing rings, inner and outer races.

Induction Heating is a flame-free, no-contact heating method that can turn a precisely defined section of a metal bar cherry red in seconds. How is this possible?

How Induction Heating works?

Alternating current flowing through an induction coil generates a magnetic field. The strength of the field varies in relation to the strength of the current passing through the coil. The field is concentrated in the area enclosed by the coil; while its magnitude depends on the strength of the current and the number of turns in the coil. (Fig. 1) Eddy currents are induced in any electrically conductive object—a metal bar, for example—placed inside the induction coil. The phenomenon of resistance generates heat in the area where the eddy currents are flowing. Increasing the strength of the magnetic field increases the heating effect. However, the total heating effect is also influenced by the magnetic properties of the object and the distance between it and the coil. (Fig. 2) The eddy currents create their own magnetic field that opposes the original field produced by the coil. This opposition prevents the original field from immediately penetrating to the center of the object enclosed by the coil. The eddy currents are most active close to the surface of the object being heated, but weaken considerably in strength towards the center. (Fig. 3) The distance from the surface of the heated object to the depth where current density drops to 37% is the penetration depth. This depth increases in correlation to decreases in frequency. It is therefore essential to select the correct frequency in order to achieve the desired penetration depth.

what is advantages of induction heating,brazing,hardening,melting and forging,etc?

Why choose induction heating over open flame,convection,radiant or another heating method?Here’s a short summary of the major advantages that modern solid state induction heating offers for lean manufacturing:

*Heating Fast

Induction heating is induced within the part itself by alternating electrical current. As a result, product warpage, distortion and reject rates are minimized. For maximum product quality, the part can be isolated in an enclosed chamber with a vacuum, inert or reducing atmosphere to eliminate the effects of oxidation. Production rates can be maximized because induction works so quickly; heat is developed directly and instantly (>2000º F. in < 1 second) inside the part. Startup is virtually instantaneous; no warm up or cool down cycle is required. The induction heating process can be completed on the manufacturing floor, next to the cold or hot forming machine, instead of sending batches of parts to a remote furnace area or subcontractor. For example, a brazing or soldering process which previously required a time-consuming, off-line batch heating approach can now be replaced with a continuous, one-piece flow manufacturing system.

*Heating Consistent

Induction heating eliminates the inconsistencies and quality issues associated
with open flame, torch heating and other methods. Once the system is properly calibrated and set up, there is no guess work or variation; the heating pattern is repeatable and consistent. With modern solid state systems, precise temperature control provides uniform results; power can be instantly turned on or shut off. With closed loop temperature control, advanced induction heating systems have the capability to measure the temperature of each individual part. Specific ramp up, hold and ramp down rates can be established & data can be recorded for each part that is run.

*Heating Clean

Induction heating systems do not burn traditional fossil fuels; induction is a clean, non-polluting process which will help protect the environment. An induction system improves working conditions for your employees by eliminating smoke, waste heat, noxious emissions and loud noise. Heating is safe and efficient with no open flame to endanger the operator or obscure the process. Non-conductive materials are not affected and can be located in close proximity to the heating zone without damage.

*Save Energy

Tired of increasing utility bills? This uniquely energy-efficient process converts up to 90% of the energy expended energy into useful heat; batch furnaces are generally only 45% energy-efficient. And since induction requires no warm-up or cool-down cycle, stand-by heat losses are reduced to a bare minimum. The repeatability and consistency of the induction process make it highly compatible with energy-efficient automated systems.

Annealing Metal Stamp With Induction

Objective: Induction Heating the opposite end of a metal stamp so that it mushrooms instead of cracks/splits when struck by a hammer.

Material S-7 steel of varying rectangular cross sectional sizes

Temperature 1400-1800 ºF (760-982) ºC

Frequency 300 kHz

Equipment DW-UHF-10KW, induction heating system, equipped with a remote heat station containing two 1.5 μF capacitors for a total of 0.75 μF and three different induction heating coils designed and developed specifically for this application.

Process One five-turn and two four-turn helical coils are used to heat the end of stamps to the required temperature. Two part sizes can be run in each of coils, using the same machine settings except for cycle time. Cycle rates dependent upon the crosssection size. The 3/8″ (0.9525 cm) square size is has a rate of below 10 seconds. The rate for the middle size, ½” – 1 ½ ” (1.27 – 3.81 cm) is 30 to 60 seconds. A 1″ (2.54 cm) square part takes approximately two minutes. Fixturing can influence the length of the cycle time required. For shorter heat times a larger power supply may be used.

Results/Benefits Precise heat only to the area that needs annealing is more efficient and repeatable than heating with a torch.

 

What Is Induction Heating?

Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction, where eddy currents (also called Foucault currents) are generated within the metal and resistance leads to Joule heating of the metal.Induction heating is a form of non-contact heating,when alternating current flows in the induced coil, varying electromagnetic field is set up around the coil, circulating current(induced, current, eddy current) is generated in the workpiece(conductive material), heat is produced as the eddy current flows against the resitivity of the material.The basic principles of 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.

induction_heating_principle

induction_heating_principle

How Induction Heating Work?

An induction heater (for any process) consists of an induction coil (or electromagnet), through which a high-frequency alternating current (AC) is passed. Heat may also be generated by magnetic hysteresis losses in materials that have significant relative permeability. The frequency of AC used depends on the object size, material type, coupling (between the work coil and the object to be heated) and the penetration depth.High Frequency Induction heating is a process which is used to bond, harden or soften metals or other conductive materials. For many modern manufacturing processes, induction heating offers an attractive combination of speed, consistency and control.

What’s Induction Heating Applications

Induction heating is a rapid ,clean, non-polluting heating form which can be used to heat metals or change the conductive material’s properties. The coil itself does not get hot and the heating effect is under controlled. The solid state transistor technology has made induction heating much easier,cost-effective heating for applications including soldering andinduction brazing ,induction heat treating, induction melting,induction forging etc.