Continuous Mesh Belt Tempering Furnace

Product Overview

The continuous mesh belt tempering furnace is an automatic continuous heat treatment unit. Quenched workpieces are loaded at one end, carried through heating, holding and cooling sections on a moving belt, and discharged at the other end ready for inspection. Its work is narrow and important: relieve the stress left behind by quenching, bring hardness down to the drawing, and restore toughness so the parts survive grinding, straightening and service.

Tempering is the step that follows hardening. Parts coming off a quench press, a batch quench tank or an in-line quench section are hard but brittle, and their hardness usually sits above the finished specification. A controlled heat-and-hold cycle lets the structure relax, and the exit hardness is decided by the temperature and by the time each part spends at that temperature rather than by guesswork at the door.

The furnace is built as a long horizontal tunnel with automatic feed and discharge, so the operator sets the run and checks the output instead of handling every basket. Parts travel on a mesh belt in the standard configuration; a roller hearth conveying system is available where the parts are heavier, longer or need support across the full width.

We are heat treatment furnace manufacturers based in Changxing, Zhejiang, and each continuous tempering furnace we build is configured around the buyer's parts, takt time and quench line rather than picked from a stock list.

Applications & Workpiece Fit

• Fasteners and threaded parts. Bolts, nuts, screws and studs are tempered in bulk on the belt; uniform time at temperature keeps hardness consistent from the first piece of a run to the last, which is what holds torque and tensile results inside specification.
• Springs. Compression, tension and torsion springs are tempered after forming and quenching, where the soak decides the balance between resilience and brittleness.
• Bearing parts. Rings, rollers and housings are stress relieved after quench and before grinding, which lowers the risk of cracks opening up during the grinding pass.
• Gears and chain components. Gear blanks, sprockets, pins and chain links travel through the same continuous flow as the rest of the transmission parts in the plant.
• Automotive and machinery structural parts. Brackets, shafts, linkages and housings quenched in a separate cell can be tempered on a schedule that follows the assembly line's call-off.
• Hardware, stampings and forgings. Small pressed and forged pieces that arrive mixed in bins are spread across the belt and tempered without the basket handling a batch furnace demands.
• Parts hardened in a box type heat treatment furnace. Quenching in a batch furnace does not tie tempering to a batch cycle; the two operations can run on different schedules, with hardening keeping its batch rhythm while tempering runs continuously against it.
• Plants where an industrial box furnace has become the bottleneck. Where the tempering queue rather than the hardening rate limits output, moving this step onto a continuous furnace clears it without changing how the parts are hardened.

Process Flow Through the Furnace

1. Load at the inlet. Parts are spread evenly across the belt, in a single layer where the geometry allows. The loading pattern matters as much as the setpoint: a thin patch beside a heap will temper differently from the rest of the run.
2. Heat to tempering temperature. The first zones raise the load to temperature. Each zone has its own controller, so the entry zones can work harder on a cold load without dragging the later zones off setpoint.
3. Hold through the soak. Belt speed sets the dwell time at temperature, and dwell plus temperature decide the final hardness. Change the part or the hardness target and the speed is reset — the chamber itself does not need rebuilding.
4. Cool in the cooling section. Parts come down in a controlled way instead of dropping into room air, so the freshly tempered structure is not stressed a second time on the way out.
5. Discharge continuously. Parts leave at the outlet end, warm but handleable with the right gloves and containers, and move straight into the next operation instead of waiting in a cooling queue in front of the furnace.
6. Check and record. Hardness samples are taken from the run, and setpoints, belt speed and sample results are logged, so any batch can be traced back to the conditions it was tempered under.

Tempering Results and Line Fit

• Hardness that holds across the run. Because every part passes the same zones at the same speed, the first and last piece of a shift see the same thermal history, and scatter between batches drops compared with load-based tempering.
• Quenching stress relieved. The hold at temperature lets the internal stress from quenching relax, which is what stops parts moving after machining or cracking in service.
• Toughness restored without falling below the hardness call-out. Temperature and dwell are balanced against the drawing, so the part gives up brittleness without giving up strength.
• Fewer losses at the next operation. Stress-relieved parts grind, straighten and finish with fewer rejects; most tempering problems show up as cracks in the grinding shop rather than at the furnace.
• Throughput that keeps pace with the quench side. A continuous tempering furnace matches the output of a continuous quench line, so hardened parts do not sit in a queue waiting for a chamber to be loaded.
• Built by a heat treatment furnace supplier who also builds the quench side. We build continuous quench furnaces and quenching and tempering lines as well, so belt width, transfer height and takt can be agreed between the two machines instead of patched together on site.
• A record for every run. Setpoints, belt speed and hardness samples are kept per run, which is the evidence a customer audit usually asks to see.

Continuous and Batch Tempering Compared

Batch and continuous tempering do the same metallurgical job, and the choice is really about how the work arrives. In a box type heat treatment furnace, a load is stacked, the door is closed, the chamber soaks, and the load cools before it can be unloaded. Every load carries its own thermal history, the parts nearest the door see a slightly different curve from the parts at the back, and the furnace sits idle while it is being filled and emptied. A continuous tempering furnace removes all three effects at once: parts travel through fixed zones at a fixed speed, loading is a conveyor rather than a crane lift, and the chamber never waits for the next basket. Batch furnaces still earn their place, for one-off heavy parts, for very small lots and for work that cannot be laid on a belt. The continuous machine wins when the same family of parts repeats week after week, when the quench side already runs continuously, and when labour at the furnace door is a real cost. One boundary is worth settling early. Tempering is normally carried out in air, and the light oxide that forms is removed by the next operation; only where the drawing calls for a bright surface does the chamber need to be built as a controlled atmosphere heat treatment furnace.

Configuration & Sizing

Multi-zone temperature control. Each heating zone runs on its own temperature controller rather than one controller governing the whole chamber. A cold load pulls heat out of the entry zones as it arrives; independent control lets those zones recover without disturbing the zones that hold parts at tempering temperature, and that is where hardness consistency comes from. Continuous mesh belt conveying. The belt runs at an adjustable speed and carries parts in at one end and out at the other, with automatic feed and discharge. Belt speed is the variable that sets the soak, so moving from one part to another is a speed change and a setpoint change rather than a new cycle recipe. Where a part is too heavy or too long for a belt, roller hearth conveying is offered on the same furnace concept. Energy-saving insulation structure. The chamber is lined to hold heat in, which shows up twice: lower running cost per tonne tempered, and a workshop that stays comfortable around the machine. Less heat lost through the lining also means the zones recover faster once a heavy load has passed. Designed for 24-hour running. These furnaces are built for continuous industrial production, not for a few cycles a day. Running continuously is gentler on the lining than repeated heat-up and cool-down, and daily attention is limited to belt tracking, the discharge end and the readings on the controllers. Sized as a custom heat treatment furnace. Chamber length, number of zones, belt width and loading height are set against your parts and your output target. That is the difference between a furnace that runs your whole part family comfortably and one that fits only the sample part it was quoted on.

Build, Spares & Safety

• Chamber and lining. A welded steel shell carries a lined chamber that holds the heat where it belongs, with panels and access points placed so the lining and heating elements can be inspected without dismantling the line.
• The mesh belt is the main wear item. It carries every part through every zone and takes the thermal cycling with them. Belt tension and tracking are checked at routine stops, and a spare belt on the shelf turns a wear-out into a planned change instead of a lost week.
• Drive and tensioning. The belt runs on a variable-speed drive with a tensioning arrangement at the return end. A new belt stretches during its first weeks, so tension is set at commissioning and adjusted again after the first production period.
• Hot-surface safety. The chamber side carries hot-surface warning signage for a reason; walkways, cable routing and the discharge bench should keep clear of the shell, and the outlet needs a container that can take parts arriving without a pause.
• Safety schedule agreed with the drawing. Over-temperature protection, belt-tracking limits and drive interlocks are settled at drawing approval rather than left to site wiring, so ask for the safety schedule together with the general arrangement.
• Spares listed against your build. Because each unit is a custom heat treatment furnace, the spare parts list is written for the chamber you buy — thermocouples, controllers, belt and drive components — so reordering later does not depend on anyone remembering the specification.

Ordering Notes

1. Send the part and process data. Material, part size and weight, how the parts will sit on the belt, the hardness target after tempering, where the parts are quenched today, and the output you need per shift. Those answers decide most of the furnace.
2. Tell us what the furnace replaces. If parts currently come off an industrial box furnace or from a batch quench tank, include the batch size and the cycle you run today; the comparison shows where the queue sits and how much belt width the new furnace needs.
3. Approve the general arrangement. We issue a drawing showing chamber length, zone layout, belt width, loading height and the inlet and outlet positions. Check it against floor space, the handling method at each end and the route to the next operation before fabrication starts.
4. Confirm commercial terms in writing. As a heat treatment furnace supplier we quote each furnace individually, so price, lead time, payment terms, packing, shipping and the warranty period are all fixed in the written quotation and the contract rather than assumed from a catalogue.
5. Plan power, foundations and services. Confirm the incoming power supply and electrical standard at your site, the control cabinet position, floor loading, and ventilation for the working area; export orders also need the drawing set and nameplate language agreed early.
6. Agree installation, commissioning and training. Our engineers support installation, commissioning, first production runs and operator training, with the scope, the site responsibilities and the acceptance checks written into the contract.
7. Agree documents and running spares. Manual, drawings, spare parts list and the recommended running spares, including a spare mesh belt, are settled before shipment so the furnace is not waiting for a part in its first month.

Technical Support & Model Matching

We build industrial heat treatment furnaces to order, so selection starts with your workpiece, material and output target rather than a catalogue number. Send us your drawings, process aim and site conditions; our engineers will compare the furnace types that fit, set the temperature zoning and handling arrangement around your parts, and confirm the layout with you before production begins. Custom work adjusts chamber dimensions and control configuration, while safety circuits and atmosphere safety components stay as designed. After delivery we remain reachable for start-up questions, fault finding and spare parts.

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