Pit Type Gas Nitriding Furnace Manufacturer | High Load Capacity & Low Operation Cost

Pit type gas nitriding furnace is a vertical cylindrical sealed heat treatment furnace with controlled atmosphere. Workpieces are suspended and loaded into the sealed chamber. Liquid ammonia or nitrogen-hydrogen mixed gas is fed into the furnace under 500~580℃ for gas nitriding, to harden and improve wear & corrosion resistance on steel workpiece surface.

1.Workpieces such as gears, shafts and moulds are hung on fixtures and lifted into the furnace by overhead crane, then furnace cover is tightly sealed.

2.The chamber is heated to 500~580℃, and liquid ammonia is continuously vaporized and decomposed into active nitrogen atoms under high temperature.

3.Active nitrogen atoms permeate into the workpiece surface to form hard nitride layers of Fe₃N and Fe₄N.

4.After heat preservation, parts cool down inside the furnace to obtain finished nitrided components with high hardness and anti-corrosion performance.

1.Furnace Body: Vertical cylindrical steel construction with multi-layer refractory and thermal insulation lining, pit-type underground installation.

2.Heat-resistant Retort: Fully sealed stainless steel liner to avoid gas leakage and stabilize atmosphere concentration.

3.Top Hot Air Circulation System: High-temperature circulating fan mounted on furnace top for uniform airflow and consistent nitriding depth.

4.Ammonia Supply System: Liquid ammonia tank, vaporizer, flowmeter, gas pipeline and tail gas burning device.

5.Electric Control System: PLC + intelligent PID temperature controller, automatic control of heating curve and ammonia decomposition rate with over-temperature interlock protection.

6.Furnace Cover Locking Unit: Hydraulic/electric sealing structure to guarantee excellent air tightness.

1.Uniform nitrided layer: Forced inner circulation ensures tiny tolerance of hardness and penetration depth among batch products.

2.Superior tightness: Sealed retort cuts ammonia consumption and reduces production cost; tail gas is safely incinerated.

3.Low thermal deformation: Process at around 500℃ far below quenching temperature, ideal for precision shafts and delicate moulds with minimal distortion.

4.Large loading capacity: Deep vertical cavity allows bulk vertical hanging for mass production.

5.Multi-process compatible: Supports conventional gas nitriding, nitrocarburizing and oxidizing nitriding.

1.Auto Parts: Transmission gears, crankshafts, valves, piston pins, synchronizer gears and chassis pins.

2.Precision Moulds: Plastic injection mould, die-casting & stamping mould for better wear resistance and anti-sticking property.

3.Hydraulic & Construction Machinery: Piston rods, cylinder shafts, hydraulic pump gears and valve components.

4.Fastener & Bearing: Precision bearing races, special high-strength bolts and textile machine fittings.