Material state
Grade, hardening process, incoming hardness, surface condition and contamination sensitivity.
Post-quench heat treatment
Vacuum Tempering Furnace
Configure bright tempering and stress-relief cycles around the material, target properties, working temperature, load geometry, vacuum package, cooling method and acceptance plan.
700°CNi-Cr heating package reference maximum
1100°CMolybdenum heating package reference maximum
2 vacuum routesTwo-stage or three-stage pumping packages
2 loading layoutsHorizontal or vertical, selected by part geometry
Application fit
Select by hardened condition and target result
Vacuum tempering reheats hardened or previously heat-treated loads under vacuum or protective gas to establish the required hardness, toughness, stress and surface condition.
Discuss material and cycle-
Tool steels
Balance hardness, toughness and residual stress
Define the grade, hardening route, incoming hardness, tempering setpoint, soak logic and required final hardness before selecting the furnace package.
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High-speed and mould steels
Plan repeat cycles and load consistency
Multiple tempering cycles, fixture mass and part section thickness determine recovery time, temperature uniformity and production throughput.
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Alloy steels
Protect the post-quench surface condition
Vacuum level, cleanliness, partial-pressure gas and cooling sequence are selected together when bright surface retention and controlled oxidation are project requirements.
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Special materials
Material compatibility governs configuration
Titanium alloys, magnetic materials, electrical iron and copper-alloy projects require material-specific evaluation of temperature, atmosphere, contamination sensitivity and acceptance criteria.
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Slender parts
Loading direction supports distortion control
For tubular, long or thin-wall components, a vertical top- or bottom-loading arrangement can support a more suitable fixture and deformation-control strategy.
Five-step selection route
Turn the tempering cycle into an equipment specification
Furnace size follows the process window and production load rather than chamber dimensions alone.
Target result
Final hardness range, stress-relief objective, dimensional tolerance and visible surface criteria.
Thermal cycle
Setpoint, ramp, soak, number of cycles, recovery requirement and load thermocouple plan.
Load and cooling
Part envelope, batch mass, fixture mass, orientation, gas pressure and unload temperature.
Acceptance
Uniformity, vacuum performance, data records, alarms, utilities and sample-part qualification.
System definition
Match the heating, vacuum and loading architecture
- Heating package
Ni-Cr and molybdenum configurations cover different temperature envelopes. Select from the required setpoint, margin, atmosphere and hot-zone life strategy.
- Heat transfer
For lower-temperature, high-mass loads, an engineered convection option can improve heating rate and temperature distribution. Fan, gas and cleanliness form one coordinated package.
- Vacuum system
Rotary-plus-Roots and rotary-plus-Roots-plus-diffusion-pump routes serve different base-pressure requirements. Specify the required pressure at a stated chamber and degassing condition.
- Loading layout
Horizontal loading supports common batch handling; vertical loading can better suit long, tubular or thin-wall parts where fixture direction is central to distortion control.
- Cooling route
Define gas type, pressure, fan operation, load density, target unload temperature and permitted cooling time instead of specifying pressure alone.
- Vessel and utilities
A double-wall water-cooled vessel requires confirmed water flow, inlet temperature, pressure, quality and interlocks as part of the installation interface.
Configuration matched to the actual load
Part drawings, fixture mass, operating temperature, vacuum level and cooling target establish the heating and pump package.
Request furnace configurationReference configuration envelope
VTH reference configurations for furnace selection
The VTH platform covers common post-quench tempering loads with heating, vacuum and cooling packages selected for the specified process window.
- Usable-zone examples
- 300 × 300 × 500 to 800 × 800 × 1200 mm Width × height × depth reference range; other dimensions are available.
- Reference load range
- 100–1000 kg Final capacity depends on part and fixture geometry, material and thermal-cycle performance.
- Ni-Cr package
- Up to 700°C For suitable tempering and stress-relief temperature windows.
- Molybdenum package
- Up to 1100°C Selected where the required operating envelope exceeds the Ni-Cr route.
- Vacuum package options
- Better than 4 × 10−1 Pa or 4 × 10−3 Pa Defined by pump train under agreed empty, clean, dry and degassed conditions.
- Gas cooling reference
- 2 bar Cooling result is qualified with gas, fan, load and temperature conditions stated.
Final usable zone, load, heating power, vacuum level, temperature uniformity and cycle performance are documented for the specified part, fixture, utilities and acceptance conditions.
Receive a VTH configuration data sheet aligned with the working zone, load and required process temperature.
Request configuration dataControl and traceability
Control architecture for repeatable tempering cycles
Recipe execution, batch records and protective interlocks operate as one coordinated system from heat-up through controlled cooling.
- 01Cycle executionRamp, soak, pressure, gas and cooling steps run through controlled recipes and user permissions.
- 02Traceable recordsTime, temperature, vacuum, alarms and batch identifiers support production and quality review.
- 03Interlocked protectionDoor, vacuum, heating, cooling water, gas and overtemperature permissives protect the process and equipment.
- 04Defined fault responsePower, water, gas, pump and sensor faults trigger specified safe states and recovery procedures.
Control language, batch data, user access and plant interface are configured for the project.
Configure control systemAcceptance planning
Tie each purchase requirement to a verification method
FAT/SAT acceptance links every critical requirement to a defined condition, instrument, load state, record and acceptance limit.
Swipe horizontally to review all acceptance columns.
| Acceptance area | Define before order | Verify with | Record in |
|---|---|---|---|
| Thermal performance | Setpoints, usable zone, uniformity limit, empty or loaded condition and sensor layout. | Calibrated survey instruments and an agreed test method. | Temperature survey report and calibration records. |
| Vacuum performance | Target pressure, pump train, chamber condition, evacuation time and pressure-rise test method. | Blank, clean, dry and degassed chamber test under stated utilities. | Pump-down curve, pressure-rise result and instrument status. |
| Load outcome | Reference parts, fixture, cycle, hardness, dimensions and visible surface criteria. | Witness load or agreed customer sample with controlled incoming condition. | Batch curve, inspection result and deviation log. |
| Cooling | Gas, pressure, load, fan logic, target unload temperature and maximum time. | Instrumented representative load where cycle time is contractual. | Cooling curve and utility conditions. |
| Safety and controls | Permissives, alarms, emergency states, access levels, recipes and data export. | Cause-and-effect checks and simulated fault conditions. | FAT checklist, alarm list and operator handover. |
Hardness, microstructure, dimensional change and appearance depend on the material, incoming state, recipe, loading and handling. Agreed samples and inspection methods establish these acceptance results.
FAT/SAT scope can include thermal survey, vacuum performance, witness loads, cooling curves, interlock checks and production records.
Define FAT/SAT scopeRFQ checklist
RFQ data for an application-matched furnace
These six data groups align chamber size, heating package, pumps, cooling, loading and acceptance scope with the production requirement.
Submit your tempering requirement- 01 · MaterialGrade, part drawing or envelope, incoming heat-treatment state and contamination restrictions.
- 02 · ResultFinal hardness or stress-relief objective, surface criteria, distortion tolerance and inspection method.
- 03 · CycleMaximum setpoint, ramp, soak, repeat tempering, cooling target and required cycle time.
- 04 · LoadNet part mass, fixture mass, quantity per batch, orientation and planned batches per day.
- 05 · SitePower supply, cooling water, process gas, compressed air, floor space and installation constraints.
- 06 · AcceptanceFAT/SAT scope, survey standard, vacuum test, sample load, documents, language and data interface.
Engineering resources
Build the process and maintenance evidence around the furnace
Cycle qualificationVacuum tempering after hardeningPlan the recipe, load thermocouples, hardness checks and release evidence.
Load designDistortion control through fixturingConnect part support, spacing, loading direction and cooling to dimensional results.
MaintenanceHot-zone condition monitoringTrack power drift, uniformity evidence and replacement decisions over time.
CommissioningCooling-water interlocksDefine water-quality, flow, pressure and alarm checks for safe operation.
Specification questions
Clarify the process boundary early
These answers guide initial selection; the project data sheet remains the controlled equipment definition.
Is vacuum tempering the same as vacuum annealing?
No. Tempering normally follows hardening and adjusts hardness, toughness and residual stress. Annealing serves a different metallurgical objective such as softening or broader material conditioning. The required cycle and result determine the applicable furnace route.
How are Ni-Cr and molybdenum heating selected?
Ni-Cr is the reference route up to 700°C, while molybdenum extends the reference temperature envelope to 1100°C. Selection combines operating setpoint, temperature margin, atmosphere, cleanliness and hot-zone life requirements.
When is a vertical furnace worth considering?
Long, tubular and thin-wall parts can benefit from vertical loading when gravity, fixture direction and handling make it easier to control deformation. Part drawings, load height and lifting requirements are needed to verify the layout.
Can the furnace guarantee final hardness and distortion?
Those results depend on material grade, incoming condition, hardening history, tempering recipe, fixture and cooling. They can be treated as acceptance items when the sample, incoming state, test method and limits are agreed in advance.
From process to proposal
Define the load, cycle and acceptance plan before choosing the model
Share the material, drawing, batch mass, setpoint, hardness target, surface requirement, cooling target and site utilities. SYNHTE can then map the requirement to the heating, vacuum, loading and control architecture.