Vacuum Quenching Furnace
Bright, Oxide-Free Quenching for Precision Components

In conventional quenching, the workpiece is heated in an atmosphere furnace or salt bath and then transferred through open air into a quench tank — exposing the hot surface to oxygen and producing scale, decarburisation, and discolouration. In vacuum quenching, the entire heating and quenching cycle takes place inside a sealed chamber with no atmospheric exposure at any point. The result is a bright, oxide-free surface that requires no post-quench cleaning. Vacuum quenching also produces more uniform thermal gradients during the quench, which reduces distortion — particularly important for precision components such as moulds and cutting tools.

Yes. Both the gas quenching and oil quenching furnaces support combined quench and temper cycles within a single furnace run. After the quench cycle is complete and the workpiece has cooled to the appropriate transfer temperature, the furnace can be programmed to ramp up to the tempering temperature and hold for the required soak time — all without removing the parts from the chamber. This eliminates the need for a separate tempering furnace and reduces total cycle time. The PLC control system stores the complete quench + temper programme for each material and part number for repeatable recall.

For high-alloy steels — including H13, D2, M2, 440C, and most tool steels and HSS — yes. These materials have sufficient hardenability that the cooling rate achievable with high-pressure gas quenching (typically 5–10 bar N₂) is more than adequate to achieve full martensitic transformation and the specified hardness. For lower-alloy steels with lower hardenability — such as 4140, 5140, or 8620 — gas quenching may not provide a fast enough cooling rate to achieve full hardness in thicker sections, and oil quenching is the better choice. If you are unsure whether gas quenching will achieve your required hardness for a specific material and section size, contact our engineers with the details and we will advise.

Vacuum gas quenching consistently produces lower distortion than salt bath quenching for high-alloy tool steels. The primary reason is the uniformity of the cooling medium — high-pressure gas flows around the entire workpiece surface simultaneously, producing a more symmetric thermal gradient than immersion in a liquid bath. For precision moulds and dies processed in vacuum gas quenching furnaces, dimensional distortion of ≤0.1–0.2 mm per 100 mm is commonly achieved on H13 and D2 tool steels. Actual distortion depends on part geometry, fixture design, and the specific quench pressure and gas flow pattern — our engineers can advise on fixture design for distortion-critical components.

Workpieces should be clean and dry before loading — free of machining oils, coolants, and moisture. Residual oils or coolants will outgas during pump-down and heating, increasing the time required to reach the target vacuum level and potentially contaminating the furnace interior. For components with blind holes or deep cavities, ensure that no liquid is trapped inside. No special surface coating or pre-oxidation treatment is required — unlike some atmosphere furnace processes. Workpieces should be loaded on clean stainless steel or molybdenum fixtures to avoid contamination from the fixture material at high temperatures.

A typical vacuum quench cycle for tool steel (H13, D2) consists of: pump-down to working vacuum (15–30 min), staged heating with preheat stops (60–90 min), austenitising soak (30–60 min), and gas quench to below 100°C (30–60 min depending on section size and quench pressure). Total cycle time for a quench-only run is typically 3–5 hours. A combined quench + temper cycle adds 2–4 hours for the tempering stage. Actual cycle times depend on furnace load, part section size, and the specific process requirements of the material.

Both furnace configurations require a three-phase five-wire 380V 50Hz electrical supply (rated power varies by model), a cooling water supply at 0.2–0.4 MPa with inlet temperature ≤30°C, and a supply of high-purity N₂ or Ar (for gas quenching) or vacuum quench oil (for oil quenching). A recirculating water chiller is recommended for facilities without a plant cooling water circuit. The gas quenching furnace requires a high-pressure gas storage and delivery system rated for the maximum quench pressure of the selected model. Full utility requirements are specified in the technical documentation provided at the quotation stage.

Every furnace carries a 2-year warranty on the complete system. Remote technical support is provided via video call, email, and WhatsApp with a 24-hour response commitment. Remote video commissioning is included with every order. On-site installation and operator training are available as optional services. Spare parts including heating elements, O-ring seal sets, and vacuum pump consumables are stocked and available for worldwide shipment, typically within 5–10 business days.