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2-Chamber Vacuum Furnace; DualTherm®
Direct cost advantages due to clean and dry parts (no surface
oxidation) after quenching.
No washing machine.
No maintenance or disposal of washing chemicals.
No complicated washing water chemistry.
Space and utility savings.
Significant Characteristics - DualTherm Operation
Furnace is switched off during idle periods (batch type furnace
heating up and cooling down time 2-3 hours)
Energy, cost saving.
Use of “vacuum” and inert gases, minimal quantities of carburizing
gas (l/h)
No fire precautions, no sprinkler required.
No automatic smoke vents in the roof.
No oil resistant floors and surfaces required.
No toxic gases with CO component.
No explosion hazards, no open flames.
Significant Characteristics - DualTherm Operation
multi-layer insulation
• low losses
• Insulation in segments around
Graphite heating
• high temperature uniformity
High number of Injecting tubes for vacuum carburizing
Option convective heating
Hearth Rails designed for applications >1000°C
Double thermocouple with additional conduit (comparison test)
Service door on the back of chamber
Significant Characteristics - DualTherm Treatment Chamber
• Charge weight 500 and 1000 kg (optional)
• Protective load transport with Fork lift system
Actuators and limit switches outside the chamber
• Short, consistent transport times
• Transport system tested in mass production
Significant Characteristics - DualTherm Internal Transport
• PC operating at the front side of the system
Database system for recipe storage
Recipes
Batch documentation, trending
Fault Recording
Siemens PLC type S7 300
Significant Characteristics - DualTherm System Control and Operation
Significant Characteristics - DualTherm External Transport
25% larger volume capacity.
External radial fan for homogeneous and uniform gas speed
distribution over the load.
Precise reproducibility via accurate control of carbon gas flow
All moving mechanical devices including the transport system
drives are outside the vacuum environment . They remain at room
temperature and are accessible for maintenance at any time.
These systems are never exposed to carburizing atmosphere or
vacuum.
Significant Characteristics - DualTherm
Significant Characteristics - DualTherm
Convective heating for faster cycles and minimized distortion and
faster to temperature uniformity.
Reversible gas flow during quenching.
Dynamic-Quench®
Can be integrated into automated lines.
DualTherm - Features
Significant Characteristics - DualTherm
Thermal and thermo-chemical heat treatment under vacuum or inert gas with
temperatures to 1250°C (2280°F).
Annealing of 150° – 1250°C in vacuum or partial pressure (N2, Ar, H2).
Hardening in vacuum or partial pressure
Vacuum Carburizing (Low Pressure Carburizing or LPC).
Carbo-nitriding in a vacuum
Brazing in vacuum or partial pressure
Combinations of methods such as soldering with subsequent hardening
Applications - DualTherm
A view from the quench chamber site glass
Note:
• 3 hearth rails
• Longitudinal heating elements
• 2 Forks (2200 lbs capacity)
Internal - DualTherm
Manually opening front door
Position workload in the chamber
Start automatic sequence
Evacuation begins within entry/quench chamber
After thermal treatment, automatic transport to quench
Automatic backfill to recipe defined pressure
Automatic Quench Fan Start
Transformation
Gas Quench Advantages – DualTherm
Shortly after cooling fan started Approximately 5 seconds later
DualTherm
Reversing Gas Flow Increased Quenching Uniformity
Modular Design Flexible and Expandable
Compact Chamber Design Short Gas Recycling Cycles,
reduced consumption
Gas flow
bottom -> top
Gas flow
top -> down
High Pressure Gas Quench Advantages - DualTherm
300
320
340
360
380
400
420
440
460
No reversing With reversing
Co
re h
ard
ne
ss
at
Mid
-to
oth
/ H
V3
0
Bottom min
Bottom average
Bottom max
Top min
Top average
Top max
Gas flow Gas flow
300
310
320
330
340
350
360
370
380
390
400
No reversing With reversing
Co
re h
ard
ne
ss
at
To
oth
ro
ot
/ H
V3
0
Bottom min
Bottom average
Bottom max
Top min
Top average
Top max
Gas flow Gas flow
300
310
320
330
340
350
360
370
380
390
400
No reversing With reversing
Co
re h
ard
ne
ss
at
Bu
lk / H
V3
0
Bottom min
Bottom average
Bottom max
Top min
Top average
Top max
Gas flow Gas flow
Bulk
Tooth
root
Mid-
tooth
Core hardness with and without reversing the gas flow
Modified SAE 5120
Option – Reverse Gas Flow
Convection ( 2 bar N2 )
(surface / core) Vacuum (surface / core)
Temperature dispersion: between surface und core one charge of bolts (540 kg gross, d = 25 mm)
0 60 120 180 240 300
800
600
400
200
0
Temperature (oC)
Time (min)
Advantages of the convective heating: shorter heating time uniform heating => reduced distortion
Option – Convection Heating
Internal access via full opening rear service door
No cables, hoses, motors or switches within the hot zone
Special tools for service and maintenance included
Transport motors, switches and adjustments from outside the
chamber
Maintenance - Service
High system availability
Low maintenance cost and spare parts requirements
Potential for high carburizing temperatures shortening process times
Low gas consumption during hardening
No cleaning of parts after heat treatment
No flame curtain
No risk of fire caused by oil fumes
Work cell friendly due to cold wall technology
Flexible use for different processes
Proven designs, used in mass-production on ModulTherm®
Customer Advantage
Customer Advantage
For more information contact us at:
ALD Vacuum Systems, Inc. 50477 Pontiac Trail Wixom MI 48393 (248) 956-7610
www.ALDVac.com
