DW-HF-15 High Frequency Induction Heater for Brazing, Hardening and Metal Heating

Quick Answer: The HLQ DW-HF-15 is a compact, single-phase high-frequency induction heating machine designed for localized heating of conductive metal components. Its primary applications include induction brazing, small-part surface hardening, annealing, shrink fitting, preheating and selected small-scale metal heating operations. The original product page specifies a 220V single-phase, 50/60Hz power supply, an operating voltage range of AC 180–250V, adjustable output power of 3–15kW and an oscillation frequency of 10–80kHz. The system uses an induction heating inverter, a matching circuit and a water-cooled induction coil to generate controlled electromagnetic heating.

Best-Fit Applications: Copper and brass tube brazing, HVAC fittings, carbide tool brazing, small steel shaft hardening, bearing and sleeve heating, small metal-part annealing and localized industrial preheating.

Engineering Selection: The DW-HF-15 should be selected according to material properties, workpiece dimensions, effective heated mass, target temperature, required heating time, induction coil design and cooling conditions. Its published electrical ratings, frequency range and continuous-duty claims require confirmation against the exact supplied machine specification because related HLQ product pages contain different values.

Table of Contents

1. What Is the DW-HF-15 High Frequency Induction Heater?
2. Key Applications
3. Suitable Materials
4. Working Principle
5. Technical Specifications
6. Recommended Model Selection
7. Process Workflow
8. Common Problems and Solutions
9. Engineering Selection Guide
10. Advantages and Limitations
11. Why Choose HLQ?
12. 10 Core FAQs

What Is the DW-HF-15 High Frequency Induction Heater?

The DW-HF-15 High Frequency Induction Heater is a compact industrial induction heating system developed for small and localized metal-heating applications. It uses high-frequency alternating current to generate an electromagnetic field through a specially designed copper induction coil.

When an electrically conductive workpiece is placed within the effective magnetic field, induced electrical currents produce heat inside the metal. The resulting heating pattern depends on the operating frequency, coil geometry, workpiece material and heating duration.

Unlike direct-flame heating, induction heating does not require a burner flame at the workpiece. Heating power can be adjusted through the induction generator, allowing the process to be adapted to different components.

The DW-HF-15 is particularly relevant to workshops, industrial maintenance departments, brazing stations, tool manufacturing and small-part heat-treatment operations.

It is not automatically suitable for every metal, heating depth, production rate or melting application. The induction power supply and heating coil must be matched to the specific process.

DW-HF-15 Product Overview

Major Components of a High Frequency Induction Heating System

Key Applications

The DW-HF-15 can be considered for several industrial heating processes. Each application requires a suitable workpiece, induction coil and operating procedure.

For small conductive components, high-frequency induction heating can provide localized heat input without requiring the entire component to be placed in a conventional furnace.

1. Induction Brazing of Copper Tubes

Induction heating is used to raise copper tube joints and compatible fittings to the temperature required by a selected brazing filler metal.

The induction coil should be designed to heat the joint region sufficiently for filler metal wetting and capillary flow.

For copper-to-copper brazing, suitable copper-phosphorus or copper-phosphorus-silver filler metals may be used according to the joint specification.

For copper-to-brass or other dissimilar-material joints, filler compatibility, flux requirements and temperature distribution must be reviewed separately.

Learn more about induction brazing copper tubes and fittings.

2. Brazing Carbide Tools

Induction brazing can be used to join suitable carbide inserts to steel tool holders using qualified filler metals and joint designs.

The process must provide adequate heating of the joint while avoiding excessive thermal gradients and damage to the carbide component.

A pancake, profile or specially designed induction coil may be used depending on tool geometry.

3. Small Shaft Surface Hardening

For suitable carbon and alloy steels, induction heating can rapidly raise selected surface regions to the required austenitizing temperature.

The heated surface must then be quenched according to the approved metallurgical process.

The final hardness and hardened case depth depend on steel composition, temperature distribution, heating duration and quenching conditions.

The DW-HF-15 is a preliminary candidate for small localized hardening operations, but no universal shaft diameter or hardened case depth can be guaranteed from the published generator rating alone.

4. Metal Annealing

The equipment may be used for selected annealing or stress-relief operations involving small copper, brass, steel or stainless steel components.

Annealing results depend on the complete thermal cycle, including heating temperature, holding time and cooling conditions.

5. Induction Shrink Fitting

Induction heating can expand a metal ring, sleeve, gear or similar component before assembly onto a shaft or other mating component.

The required temperature should be calculated from material expansion properties, interference allowance and component geometry.

6. Localized Preheating

High-frequency induction heating may be used to preheat small metal parts before joining, forming or other industrial operations.

The heating zone and process temperature should be defined according to the manufacturing requirement.

7. Small-Scale Metal Melting

Small-scale induction melting may be possible with an appropriately designed crucible, induction coil and power supply configuration.

However, the published 15kW-class power rating does not establish a universal melting capacity. The metal type, melting temperature, charge mass, crucible characteristics and thermal losses must be evaluated.

Suitable Materials

Induction heating is suitable for many electrically conductive materials. However, the resulting heating performance depends on electrical resistivity, magnetic permeability, thermal conductivity, workpiece geometry and operating temperature.

The same induction coil and power setting will not necessarily produce the same heating result in different metals.

Material Compatibility

Material Selection Considerations

Working Principle

The DW-HF-15 operates according to electromagnetic induction.

An alternating electrical current flows through a copper induction coil. The coil generates a changing magnetic field around the workpiece.

When a conductive metal component is positioned within this field, electrical currents are induced inside the material.

These induced currents generate heat through electrical resistance.

For some ferromagnetic materials, magnetic losses may also contribute to heating under appropriate conditions.

The final heating distribution depends on electromagnetic coupling, operating frequency, workpiece dimensions and heating time.

Energy Conversion Process

Induction Frequency and Heating Depth

The operating frequency influences the distribution of induced electrical currents within the workpiece.

Under simplified electromagnetic conditions, higher frequencies produce smaller reference electrical penetration depths, while lower frequencies produce larger reference penetration depths.

This behavior is associated with the skin effect.

The reference skin depth for a suitable homogeneous material can be estimated using:

δ = √[ρ / (π × f × μ)]

Where:

• δ = Electrical skin depth, meters.
• ρ = Electrical resistivity, Ω·m.
• f = Operating frequency, Hz.
• μ = Absolute magnetic permeability, H/m.

Important: Electrical skin depth is not identical to the final temperature penetration depth. The actual temperature profile also depends on thermal conduction, heating time and temperature-dependent material properties.

The target DW-HF-15 page publishes an oscillation-frequency range of 10–80kHz. Other HLQ pages publish 30–80kHz or 30–100kHz for related DW-HF-15 configurations.

The exact frequency range must therefore be confirmed for the supplied machine.

Induction Coil Design

The coil is one of the most important components of a high-frequency induction heating system.

Its dimensions, number of turns, active heating length and distance from the workpiece influence the magnetic field and electrical matching.

A coil designed for copper tube brazing may not be suitable for shaft hardening, bearing heating or metal melting.

Application-specific coils should be selected according to workpiece geometry, material properties and heating requirements.

Explore HLQ’s custom induction heating coil design solutions.

Technical Specifications

The following specifications are based on the original HLQ DW-HF-15 product page.

Where related HLQ pages publish different values, the discrepancy is identified rather than replaced by an unsupported universal specification.

DW-HF-15 Published Technical Data

Important Specification Verification

Single-Phase Electrical Supply Considerations

The DW-HF-15 is published as a single-phase 220V induction heater.

Electrical supply sizing must use the manufacturer’s verified full-load input current, input power factor, conversion efficiency and required protection.

For reference, a 15kW single-phase input at 220V and unity power factor would require approximately 68.2A.

This calculation does not represent a verified DW-HF-15 input current. If 15kW is an output rating, the required input power and current may be higher.

Electrical installation and protection must be designed by qualified personnel according to applicable local regulations.

Recommended Model Selection

The appropriate induction heating machine should be selected according to the required thermal process rather than rated power alone.

The DW-HF-15 is most relevant to localized heating of relatively small workpieces. Higher-power systems or different frequency ranges may be necessary for larger components, deeper heating or increased production throughput.

Application-Based Equipment Selection

Selection Note: The recommendations above are preliminary application categories. No universal maximum workpiece diameter, heating time or hardening depth is guaranteed by these power classes.

Related High Frequency Product Families

For a broader comparison, see HLQ’s induction heating power supply selection guide.

Process Workflow

A reliable high-frequency induction heating process requires correct workpiece preparation, induction coil positioning, equipment inspection, heating control and quality verification.

The detailed production sequence varies according to whether the machine is used for brazing, surface hardening, annealing, shrink fitting or another application.

General High Frequency Induction Heating Process

Induction Brazing Workflow

For brazing, the sequence normally includes cleaning the joint, selecting the filler metal, assembling the components, positioning the coil, heating the joint, allowing filler flow, cooling and inspecting the completed joint.

Induction Hardening Workflow

For induction hardening, the component must be made from a material suitable for the required hardening process.

The selected surface region is heated to the required austenitizing condition and then quenched using the approved cooling medium and procedure.

Final hardness, hardened depth, distortion and crack resistance must be verified.

Explore HLQ’s shaft induction hardening equipment and application requirements.

Cooling Requirements

The original DW-HF-15 product page lists a cooling-water flow of 5 L/min and a temperature reference below 40°C.

These figures should be checked against the manufacturer’s current installation manual.

Cooling must protect both the induction coil and the designated internal power components.

Illustrative Cooling Water Calculation

The heat removed by a cooling-water circuit can be estimated from the water mass-flow rate and temperature increase.

P = mflow × Cp × ΔT

For an illustrative water flow of 5 L/min and a water temperature increase of 10°C, the theoretical heat removal is approximately 3.48kW.

This does not establish the actual waste-heat output of the DW-HF-15. The complete cooling system must be sized using verified equipment and process data.

Common Problems and Solutions

High-frequency induction heating performance depends on the interaction between the electrical generator, induction coil, workpiece, cooling circuit and process settings.

Engineering Selection Guide

Selecting a high-frequency induction heater requires engineering evaluation of the complete heating process.

The DW-HF-15 is a potential solution for small localized heating applications, but the correct model and coil must be selected according to the workpiece and production requirements.

Step 1: Identify the Workpiece

Specify the material grade, workpiece dimensions, weight and required heating zone.

For brazing, provide both base materials and joint geometry. For hardening, specify the steel grade and required hardness or case depth.

Step 2: Define the Target Temperature

Determine the temperature required by the process.

For brazing, the temperature depends on the filler metal and base materials. For hardening, the required temperature depends on steel grade and metallurgical requirements.

Step 3: Determine the Heating Time

Specify the required time to reach the target temperature.

Shorter heating times generally require greater average useful thermal power for the same heated mass and temperature increase.

Step 4: Calculate the Effective Heated Mass

The effective heated mass may be smaller than the entire component mass when only a local region is heated.

Use the dimensions and density of the actual heated region for preliminary calculations.

Step 5: Estimate Heating Energy

For a simplified sensible-heating calculation:

Q = m × Cp × ΔT

Where:

• Q = Useful thermal energy, kJ.
• m = Effective heated mass, kg.
• Cp = Approximate mean specific heat, kJ/kg·K.
• ΔT = Temperature increase, K.

Step 6: Engineering Calculation Example

Consider an illustrative steel component with an effective heated mass of 0.15kg.

Assume the component is heated from 25°C to 800°C, using a mean specific heat capacity of 0.55kJ/kg·K.

The theoretical useful thermal energy is:

Q = 0.15 × 0.55 × (800 − 25) = 63.94kJ

This is equivalent to approximately 0.01776kWh of useful thermal energy.

Step 7: Compare Heating Time and Power

For the same theoretical thermal energy, average useful heating power depends on heating duration.

The table below also shows an illustrative electrical-input estimate using an assumed overall electrical-to-workpiece heating efficiency of 50%.

Engineering Qualification: The values above are simplified calculations and do not represent actual DW-HF-15 measurements. They must not be compared directly with the machine’s published 15kW output without confirming the power-rating boundary and actual heating efficiency.

Step 8: Select the Induction Coil

Select an induction coil according to workpiece geometry, heating-zone dimensions, mechanical clearance and required heating pattern.

The coil must also be compatible with the generator’s operating frequency and resonant matching system.

Step 9: Verify Cooling and Electrical Supply

Confirm rated input current, voltage tolerance, electrical protection, coolant flow, pressure, water quality and temperature limits.

Do not select cables or circuit breakers solely from the nominal 15kW product name.

Step 10: Validate the Heating Process

For production applications, perform a representative heating test using the actual workpiece.

Record material, dimensions, heating time, electrical input, operating frequency, temperature and relevant quality results.

Published HLQ Application Reference

HLQ has published a separate carbide-tool brazing application using a DW-UHF-20kW induction system.

The application reports approximately 11.5kW of applied power and 10 seconds to brazing temperature for carbide-tip replacement.

This demonstrates a related induction brazing process, but it is not a DW-HF-15 test and does not establish identical performance for this model.

See the induction brazing carbide tips application for the original process description.

Recommended Factory Acceptance Test

Advantages and Limitations

Advantages of the DW-HF-15 High Frequency Induction Heater

The DW-HF-15 can offer practical advantages for suitable localized heating applications when correctly matched to the workpiece.

Limitations and Engineering Considerations

Why Choose HLQ?

HLQ Induction Equipment Co., Ltd. supplies industrial induction heating equipment for brazing, hardening, forging, annealing, melting and other metalworking applications.

The DW-HF-15 belongs to HLQ’s high-frequency induction heating equipment range and is intended for suitable compact industrial heating operations.

Application-Based Equipment Selection

Machine selection can be based on workpiece material, dimensions, heating temperature, required cycle time and available electrical supply.

Induction Coil Configuration

Different induction coils can be evaluated according to the required heating zone and mechanical accessibility of the workpiece.

Industrial Heating Applications

The equipment can be considered for copper brazing, selected steel hardening, annealing, shrink fitting and other localized heating processes.

Process Integration

Depending on the supplied machine configuration, induction heating may be combined with suitable workpiece fixtures, cycle controls and production equipment.

Engineering Verification

For important industrial applications, performance should be validated using representative workpieces, defined heating parameters and agreed acceptance criteria.

10 Core FAQs

1. What is the DW-HF-15 high frequency induction heater?

The DW-HF-15 is a compact high-frequency induction heating machine designed for localized heating of electrically conductive metal components. Typical applications include brazing, small-part hardening, annealing, shrink fitting and industrial preheating.

2. What is the rated power of the DW-HF-15?

The target product page lists a maximum output of 15kW, adjustable from 3kW to 15kW. Other HLQ literature identifies related DW-HF-15 equipment using a 15kVA rating. The exact input and output definitions should be confirmed for the supplied model.

3. Does the DW-HF-15 use single-phase electricity?

Yes. The original product page specifies single-phase 220V AC, 50/60Hz input. The published working-voltage range is 180–250V. The full-load input current and electrical protection requirements must be verified before installation.

4. What is the operating frequency of the DW-HF-15?

The target product page lists 10–80kHz. Other related HLQ pages publish 30–80kHz or 30–100kHz. The correct frequency range should be confirmed from the technical specification of the supplied machine.

5. Can the DW-HF-15 braze copper tubes?

Yes, it can be considered for suitable copper tube brazing operations. The actual performance depends on tube diameter, wall thickness, fitting geometry, brazing filler, induction coil and required heating time.

6. Can the DW-HF-15 harden steel shafts?

It can be considered for localized hardening of suitable small steel parts. Final hardness and case depth depend on material grade, austenitizing conditions, heating time and quenching. Application testing is required.

7. Does the DW-HF-15 need cooling water?

Yes. The original product page lists a cooling-water flow of 5 L/min. It also provides pressure and temperature references that require clarification. The cooling system must satisfy the manufacturer’s verified operating requirements.

8. Can the DW-HF-15 operate continuously?

The target product page claims a 100% continuous load rate, while another related page identifies an 80% duty rating. Actual continuous-duty capability must be verified for the selected machine, load, cooling conditions and ambient temperature.

9. Can one induction coil heat different metal components?

Sometimes, when the workpieces have compatible dimensions and heating requirements. However, different shapes, materials and heating zones often require different induction coils for effective electromagnetic coupling and repeatable results.

10. How do I select the correct induction heating machine?

Specify the material, workpiece dimensions, effective heated mass, initial and target temperatures, required heating time, production rate, electrical supply and cooling conditions. The equipment should then be selected through engineering calculations and, where necessary, representative heating tests.

HLQ-DW-HF-15-high-frequency-induction-heater-brochure