What factors should be considered when selecting a box type tempering furnace?

The selection of box type tempering furnace requires comprehensive consideration of multiple factors. Let’s take a detailed look below!

1. Process adaptability
Temperature parameters
Temperature range: The highest tempering temperature of the material to be covered (such as 180-680 ℃ for steel and 200-300 ℃ for aluminum alloy)
Temperature control accuracy: Precision parts require an accuracy of ± 1 ℃, while ordinary parts can achieve an accuracy of ± 5 ℃
Temperature uniformity: The temperature difference in key areas should be ≤ ± 5 ℃ (which can be verified through multi-point temperature measurement)
atmosphere control
Protective gas: Easily oxidizable materials require nitrogen/argon protection, and hydrogen reduction requires explosion-proof design
Gas flow rate: calculated based on furnace volume (usually 1-5L/min · m ³)
Sealing performance: The furnace door adopts double-layer silicone sealing strips, with a leakage rate of ≤ 0.5%
Furnace size
Loading capacity calculation: Single layer workpiece spacing ≥ 50mm, layer height ≥ 1.2 times workpiece height
Loading method: Equipped with carts/tracks for easy entry and exit of large workpieces, the laboratory can choose a layered drawer style

2. Equipment performance indicators
heating system
Heating element: Resistance wire suitable for medium and low temperatures, silicon carbon rod/silicon molybdenum rod resistant to high temperatures (1300 ℃)
Power density: It is recommended to use 15-20W/cm ² for high-temperature furnaces and 10-15W/cm ² for low-temperature furnaces
Heating rate: conventional ≤ 10 ℃/min, rapid tempering furnace can reach 30 ℃/min
thermal insulating property
Insulation layer thickness: High temperature furnace ≥ 200mm (ceramic fiber+refractory brick composite structure)
Surface temperature rise: ≤ 60 ℃ (in accordance with GB5959.1 safety standard)
Automated control
Temperature control instrument: PID intelligent temperature controller, supporting programmed heating (up to 100 segments)
Data recording: equipped with paperless recorder, storage period ≥ 1 year
Remote control: optional RS485/Ethernet interface for MES system integration

3. Security protection system
Three level protection mechanism
Overtemperature alarm: Automatic power-off when the temperature exceeds the set value by 5 ℃
Disconnect protection: Cut off power within 1 second in case of thermocouple failure
Pressure monitoring: The atmosphere furnace is equipped with pressure sensors, which automatically release pressure in case of abnormalities
structural safety
Furnace door interlock: automatic power-off when opening the door, safety must be confirmed before starting after closing the door
Explosion proof design: The hydrogen furnace adopts explosion-proof motors and explosion-proof solenoid valves, and the furnace body has at least 2 pressure relief ports
Grounding resistance: ≤ 4 Ω (in accordance with GB/T 16895.3 standard)

Selection decision tree
Requirement confirmation: Clarify material type, temperature requirements, and production scale
Technical comparison: Select 3-5 suppliers based on process parameters
Field visit: Verify the actual operating data of the equipment and test samples
Business negotiation: Focus on the warranty period (recommended ≥ 1 year) and spare parts supply cycle (≤ 7 days)

By systematically evaluating the above factors, selection errors can be effectively avoided. For example, a certain automotive parts factory had a product oxidation scrap rate of 15% due to failure to consider atmosphere sealing; And a certain aviation company reduced the residual stress of titanium alloy tempering by 40% through precise temperature control. Suggest requesting suppliers to provide third-party testing reports and sign performance guarantee agreements during procurement.