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Vacuum Gas /Oil Quenching Furnace
COOLDO CLEAN VACUUM HEAT TREATMENT
Vacuum Gas and Oil Quenching Furnace for Tool Steel and Alloy Parts
The COOLDO vacuum gas and oil quenching furnace combines vacuum heating with controlled high-pressure inert-gas cooling or vacuum-oil quenching. Single-chamber, double-chamber, three-chamber, horizontal and vertical systems are engineered for tool steel, high-speed steel, die steel, stainless steel and alloy components requiring bright surfaces, repeatable hardness and reduced oxidation or decarburization.
- Up to 1350°C
- Technical catalog maximum temperature
- Up to 25 bar
- High-pressure gas-quench reference
- ±5°C
- Catalog temperature-uniformity reference
- 60-5000 kg
- Catalog loading range by model
What Is a Vacuum Quenching Furnace?
A vacuum heat treatment furnace heats cleaned metal parts at reduced pressure, limiting contact with oxygen and other reactive gases. After austenitizing or solution treatment, the load is cooled by high-pressure neutral gas or transferred inside the sealed system to a controlled quenching-oil chamber.
This process can produce bright, clean parts with limited scale and decarburization. Final hardness and distortion depend on the steel grade, section size, loading arrangement, heating recipe, quench severity, gas flow, oil condition and fixture design. The equipment is a heat-treatment furnace, not a vacuum induction melting furnace.
- Main purpose
- Clean vacuum hardening, solution treatment and controlled cooling.
- Quench media
- High-purity neutral gas or qualified vacuum quenching oil.
- Orientation
- Horizontal or vertical load configuration.
- Selection basis
- Alloy hardenability, load geometry, hardness, distortion and output.
Clean Heating Before Controlled Quenching
Vacuum removes much of the reactive atmosphere before heating. Depending on the alloy and hot-zone design, partial pressure or inert-gas backfill may be used to protect alloying elements, improve heating behavior or limit evaporation.
After soaking, the load remains inside the sealed system for gas or oil quenching. This avoids the uncontrolled air exposure associated with transferring an open hot load between separate machines.
Vacuum Gas Quenching vs Vacuum Oil Quenching
The quench medium must be selected from alloy hardenability, section thickness, distortion tolerance and required cooling rate.
High-Pressure Vacuum Gas Quenching
After vacuum heating, the chamber is rapidly backfilled with high-purity neutral gas. A variable-frequency fan and heat exchanger circulate the gas through the load.
- Catalog gas-quench pressure up to 25 bar
- Fast and uniform cooling with low operating residue
- Single-chamber or double-chamber construction
- Common for high-speed steel, hot-work and cold-work tool steels with adequate hardenability
- Optional convection heating and step tempering
Vacuum Oil Quenching and Gas Cooling
The heated load transfers inside the sealed furnace to a controlled vacuum-quenching oil chamber; the catalog also supports combined oil-quench and gas-cooling configurations.
- Three-chamber oil/gas quenching furnace option
- Double-chamber oil-quench and gas-cooling option
- Higher quench severity for compatible steels and sections
- Oil temperature, agitation and load transfer controlled by recipe
- Oil vapor management, separation and fire protection required
Do not select by pressure alone: the achievable part cooling rate depends on gas type, pressure, fan power, heat-exchanger capacity, nozzle flow, load density, section size and furnace geometry.
Vacuum Quenching Furnace Structure and Controls
Each subsystem is sized for the complete thermal load, vacuum cycle and required quench intensity.
Vacuum Vessel and Door
A water-cooled pressure vessel, locking door, seals and feedthroughs maintain the specified vacuum and backfill pressure.
Graphite or Metal Hot Zone
Graphite insulation and heaters or an all-metal molybdenum hot zone are selected from cleanliness, temperature and material requirements.
Vacuum Pumping System
Mechanical, Roots and high-vacuum pumps are configured to reach the required operating pressure and cycle time.
Gas-Quench Circuit
Gas storage, valves, high-power fan, directional nozzles, heat exchanger and cooling water provide controlled recirculating gas flow.
Oil-Quench System
The oil tank, elevator or transfer unit, agitator, heater, cooler, separator and level monitoring control oil-quench performance.
PLC and Safety Interlocks
Automation coordinates pumping, heating, partial pressure, transfer, gas pressure, cooling, alarms and batch records.
Horizontal or Vertical Vacuum Furnace?
A horizontal vacuum gas quenching furnace provides convenient front loading for general tools, dies, fixtures and production batches.
A vertical vacuum gas quenching furnace supports long shafts, rods, plates and slender parts in a hanging orientation, helping reduce bending caused by horizontal support and high-temperature self-weight.
Typical Vacuum Hardening and Quenching Cycle
The approved recipe must be based on the exact alloy, prior condition, section size, hardness target and distortion limit.
Clean and Load
Remove oil and contamination; arrange parts and load thermocouples on qualified fixtures.
Evacuate
Pump down, leak-check and establish the specified vacuum or partial-pressure condition.
Preheat
Use controlled preheat stages to reduce thermal shock and temperature gradients.
Austenitize
Heat and soak only after the load reaches the qualified temperature criteria.
Gas or Oil Quench
Apply the selected pressure-gas cycle or transfer internally to controlled vacuum oil.
Unload and Temper
Unload at the safe temperature and temper without unnecessary delay according to the steel specification.
Inspect and Record
Verify hardness, distortion, surface condition and retained cycle data.
Vacuum Gas and Oil Quenching Furnace Reference Models
The following model families and technical data are organized from the supplied vacuum-furnace catalog. The source families HRQ, HRC2 and HRQL are shown with a CDO- prefix for this COOLDO product page. Final chamber size, usable load, vacuum package, quench pressure and acceptance conditions must be confirmed in the approved technical proposal.
CDO-HRQ Single / Double Chamber High-Pressure Gas Quenching Models
| Model | Working zone (W × H × L) | Load | Max. temperature | Uniformity | Limit pressure | Pressure rise | Gas quench |
|---|---|---|---|---|---|---|---|
| CDO-HRQ-433 | 450 × 300 × 300 mm | 60 kg | 1350°C | ±5°C | 4.0 × 10-3 / 6.7 × 10-7 mbar | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-644 | 600 × 400 × 400 mm | 200 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-755 | 700 × 500 × 500 mm | 300 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-966 | 900 × 600 × 600 mm | 500 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-1277 | 1200 × 700 × 700 mm | 800 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-1288 | 1200 × 800 × 800 mm | 1200 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-1699 | 1600 × 900 × 900 mm | 2000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQ-2100 | 2000 × 1200 × 1200 mm | 4000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
CDO-HRC2 Double / Three Chamber Oil and Gas Quenching Models
| Model | Working zone (W × H × L) | Load | Max. temperature | Uniformity | Limit pressure | Pressure rise | Gas pressure |
|---|---|---|---|---|---|---|---|
| CDO-HRC2-433 | 450 × 300 × 300 mm | 60 kg | 1350°C | ±5°C | 4.0 × 10-3 / 6.7 × 10-7 mbar | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-644 | 600 × 400 × 400 mm | 200 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-755 | 700 × 500 × 500 mm | 300 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-966 | 900 × 600 × 600 mm | 500 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-1266 | 1200 × 600 × 600 mm | 700 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-1288 | 1200 × 800 × 800 mm | 1000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
| CDO-HRC2-1599 | 1500 × 900 × 900 mm | 2000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 2 / 25 bar |
CDO-HRQL Vertical High-Pressure Gas Quenching Models
| Model | Working zone (Ø × H) | Load | Max. temperature | Uniformity | Limit pressure | Pressure rise | Gas quench |
|---|---|---|---|---|---|---|---|
| CDO-HRQL-630 | Ø600 × 300 mm | 150 kg | 1350°C | ±5°C | 4.0 × 10-3 / 6.7 × 10-7 mbar | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQL-750 | Ø700 × 500 mm | 300 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQL-890 | Ø800 × 900 mm | 700 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQL-1210 | Ø1200 × 1000 mm | 1500 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQL-1220 | Ø1200 × 2000 mm | 3000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
| CDO-HRQL-1520 | Ø1500 × 2000 mm | 5000 kg | 1350°C | ±5°C | Same family reference | 0.4-0.67 Pa/h | 6 / 25 bar |
Catalog-data note: the paired limit-pressure and quench-pressure figures represent catalog configuration alternatives, not simultaneous guaranteed values. The final pump set, clean empty-dry ultimate pressure, working pressure, pump-down time, quench pressure, measurement method and acceptance conditions must be written into the contract.
Vacuum Heat Treatment Applications
Material trials and recipe qualification are recommended before production release.
Suitable Materials and Parts
- Alloy structural steel
- High-speed steel tools
- Cold-work and hot-work die steel
- Alloy tool steel
- Spring steel
- Bearing steel
- Stainless steel parts
- Precision-alloy components
- Gears, molds and transmission parts
- Long shafts and rods
Available Processes
- Bright hardening with high-pressure gas quenching
- Vacuum heating followed by oil quenching
- Bright annealing and stress relieving
- Solution treatment for qualified alloys
- Vacuum brazing when separately configured
- Magnetic-material sintering when separately configured
- Vacuum tempering with a suitable process package
Gas quenching is not suitable for every alloy or section size. A hardenability and cooling-rate review is required before replacing oil quenching with high-pressure gas.
Information Required to Select a Vacuum Quenching Furnace
Material and Workpiece
Alloy grade, part drawing, section thickness, individual weight, total batch weight, cleanliness and fixture layout.
Heat Treatment Result
Austenitizing curve, hardness, microstructure, distortion limit, surface requirement and maximum transfer time.
Quench Requirement
Gas or oil preference, qualified cooling rate, gas type and pressure, oil specification, agitation and allowable discharge temperature.
Utilities and Compliance
Electrical supply, cooling water, nitrogen or argon supply, exhaust, floor loading, local pressure-vessel and machinery standards.
Vacuum Gas and Oil Quenching Furnace FAQs
Technical answers for vacuum hardening, gas cooling, oil quenching and clean heat-treatment projects.
What is a vacuum gas quenching furnace?
It heats parts under vacuum or controlled partial pressure, then rapidly backfills and circulates high-purity neutral gas through the load to achieve the required cooling rate and hardness.
What is a vacuum oil quenching furnace?
It heats parts under vacuum and transfers the load inside a sealed system to controlled vacuum-quenching oil. Oil temperature, agitation, load movement and inert backfill are managed by the furnace recipe.
What is the difference between gas and oil quenching?
Gas quenching is cleaner and often produces less distortion, but its cooling severity may be lower. Oil quenching provides faster cooling for many alloys and larger sections but requires oil handling, washing and stronger fire protection.
Which gas is used for vacuum gas quenching?
Nitrogen is common for compatible materials. Argon may be selected for reactive alloys or special processes. Gas purity, material compatibility, pressure and supply capacity must be confirmed for each project.
Is 25 bar gas quenching always better than 10 bar?
No. Higher pressure can increase cooling capacity, but part cooling also depends on gas type, flow, fan power, heat exchange, load density and geometry. Excessive cooling or flow can increase distortion on sensitive parts.
Which steels are suitable for high-pressure gas quenching?
High-speed steels and many high-hardenability cold-work, hot-work and alloy tool steels are common. The steel supplier data and required core cooling rate must be reviewed before process approval.
When should vacuum oil quenching be selected?
Oil quenching is considered when the alloy, section size or hardness requirement needs a cooling rate that the available gas-quench system cannot reliably provide.
Why does vacuum heat treatment produce bright parts?
Reduced oxygen and controlled gas exposure limit scale and oxidation during heating. Surface quality still depends on cleaning, furnace leak rate, hot-zone condition, partial pressure and quench medium cleanliness.
What is the maximum temperature?
The supplied technical catalog lists a maximum temperature of 1350°C for the referenced gas-quench, oil/gas-quench and vertical gas-quench model families. The qualified operating temperature depends on hot-zone material, load, process, thermocouples and required service life.
What is the difference between horizontal and vertical vacuum quenching furnaces?
Horizontal furnaces are convenient for general front-loaded batches. Vertical furnaces support long shafts, rods and slender parts in a hanging orientation to reduce high-temperature bending and handling distortion.
Can the furnace perform low-pressure carburizing?
Only when the furnace is specifically designed with a carburizing gas system, process controls, pumping protection and compatible hot zone. It is not included automatically with a standard vacuum gas-quenching furnace.
Can vacuum quenching eliminate all distortion?
No. It can improve control, but distortion also comes from prior machining stress, steel condition, geometry, fixtures, heating gradients and quench rate. The complete process chain must be optimized.
How is vacuum performance specified?
The contract should separately define clean empty-dry ultimate pressure, working pressure, pump-down time, pressure-rise rate, measurement method and acceptance conditions.
Can COOLDO customize the vacuum quenching furnace?
Yes. Hot-zone size, load, orientation, graphite or metal hot zone, vacuum pumps, gas pressure, oil quench, transfer, partial pressure, controls and data recording can be configured around the project.
What information is needed for a quotation?
Send the material grade, drawings, section size, batch weight, hardness target, heat-treatment curve, gas or oil quench preference, distortion limit, production rate and available utilities.
Planning a Vacuum Gas or Oil Quenching Project?
Send your alloy, part size, batch weight, heat-treatment curve and cooling requirement for an engineered furnace proposal.
| Model | Working size (mm) |
Ultimate pressure (pa) |
Pressure rising rate(pa/h) | Loading capacity(kg) | Cooling gas pressure(bar) |
| CDO-VQ-20 | 200*200*200 | 4*10-¹~6.7*10-³ | 0.67 | 50 | 6/10/15/20 |
| CDO-VQ-30 | 300*300*500 | 4*10-¹~6.7*10-³ | 0.67 | 100 | 6/10/15/20 |
| CDO-VQ-40 | 400*400*600 | 4*10-¹~6.7*10-³ | 0.67 | 200 | 6/10/15/20 |
| CDO-VQ-50 | 500*500*700 | 4*10-¹~6.7*10-³ | 0.67 | 300 | 6/10/15/20 |
| CDO-VQ-60 | 600*600*900 | 4*10-¹~6.7*10-³ | 0.67 | 500 | 6/10/15/20 |
| CDO-VQ-70 | 700*700*1000 | 4*10-¹~6.7*10-³ | 0.67 | 700 | 6/10/15/20 |
| CDO-VQ-80 | 800*800*1200 | 4*10-¹~6.7*10-³ | 0.67 | 1000 | 6/10/15/20 |
| CDO-VQ-v50 | Ø500*700(vertical) | 4*10-¹~6.7*10-³ | 0.67 | 300 | 6/10/15/20 |
| CDO-VQ-v70 | Ø700*900(vertical) | 4*10-¹~6.7*10-³ | 0.67 | 500 | 6/10/15/20 |
| CDO-VQ-v100 | Ø1000*1000(vertical) | 4*10-¹~6.7*10-³ | 0.67 | 800 | 6/10/15/20 |
| CDO-VQ-v120 | Ø1200*1000(vertical) | 4*10-¹~6.7*10-³ | 0.67 | 1000 | 6/10/15/20 |
| Max temperature:1320℃ , Temprtature unifromity:±5℃ |
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Vacuum technology is the basis for innovations in heat treatment processes.
Heat treatment is a process in which metal/steel parts are fully or partially exposed to a time-temperature sequence to change their mechanical and/or corrosive properties. There are many applications, such as.
-Annealing – Hardening – Tempering – Aging – Surface hardening
In order to achieve higher material strength, better wear resistance or improved corrosion resistance of components, all these processes require up to Temperatures of 1.000°C and higher and specially developed furnaces are required to reach this range.
Vacuum annealing
Annealing is a heat treatment that involves heating to a specific temperature, holding it slowly and cooling it. This type of process is usually used to obtain a softer structure of the part and to optimize the material structure for subsequent work steps (machining, forming). The parameters depend on the material and the desired structure.
Vacuum Hardening and TemperingHardening is a typical heat treatment process that involves heating to a specific temperature (mostly above 900°C) and direct rapid cooling or quenching. Parts combined. The selection requirement is to change the structure of the material partially or completely to martensite. The parts are tempered after hardening to obtain high ductility and toughness.
Vacuum Surface Hardening
One of the important processes is the surface hardening or carburizing process. The parts are heated to 900°C-1.000°C and the process is carried out by adding specific gases (hydrocarbons) to the furnace atmosphere. Absorbs carbon, thereby enriching the surface of the part. After this treatment, the part is hardened to obtain the desired properties. This increases the resistance to stress and friction on the component’s surface. The core of the part remains softer and more ductile, which exposes the part to high stresses throughout its service life.
