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Energy Saving Pit Type Nitrocarburizing Furnace With Post-Oxidation For Auto Parts & Molds
Whole set of pit nitriding furnace | Furnace body + Control Cabinet | Vertical heat treatment nitriding oven
This furnace combines gas nitriding and steam post-oxidation in a single retort, replacing toxic QPQ salt baths. It offers high corrosion resistance, minimal workpiece deformation, and fully automatic PLC control, with CE certification available.
Custom pit nitriding furnace with a post-oxidation system for the heat treatment of crankshafts, gears and moulds, featuring precise nitrogen potential control and direct supply from the manufacturer.
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Pit-type nitriding furnace with post-oxidation Overview
Vertical Pit Nitriding Furnace with In-situ Post-Oxidation (Integrated NCO Furnace)
It is vertical sealed pit-type furnace integrating gas nitriding and steam post-oxidation inside one retort, replacing traditional toxic cyanide QPQ salt bath process with eco-friendly design. All procedures including nitriding and blackening oxidation are finished in single batch loading. The workpiece forms composite structure: Base metal → Nitrogen diffusion layer → White nitride layer → Dense Fe₃O₄ black oxide coating, bringing excellent wear resistance and corrosion resistance with matte black finish and minimal thermal deformation.
Five Core Components of Complete Equipment
Welded steel plate furnace body with full fiber aluminum silicate insulation liner, outstanding thermal insulation, saving over 25% power during idle heating and fast temperature rising.Max design temperature: 650℃; Working range: 520~570℃ for nitriding, 380~430℃ for post-oxidation.
Made of high-nickel heat-resistant stainless steel against ammonia corrosion & high-temperature creep deformation. Equipped with double water-cooled sealed furnace cover and hydraulic opening-closing system plus rubber vacuum sealing, excellent air tightness to cut ammonia consumption by over 30%.Top-mounted high-temperature circulating fan realizes uniform atmosphere circulation, furnace temperature uniformity ≤±3℃, nitride depth tolerance less than 0.02mm.
1.Nitriding circuit: Liquid ammonia vaporizer + precision mass flowmeter, automatic ammonia flow & nitrogen potential adjustment, freely switch between conventional nitriding and nitrocarburizing.
2.Post-oxidation circuit: Independent stainless steel pure water steam generator. After nitriding finished, saturated steam is directly fed into chamber for in-situ oxidation without unloading workpieces or extra oxidation furnace.
Full automatic cycle program: Heating → Nitriding holding → Cooling for oxidation → Furnace cooling, unattended running.Functions include nitrogen potential monitoring, overheat/overpressure/gas leakage interlock alarm, temperature curve recording & data export for digital workshop production.
High-temperature ammonia incinerator for harmless exhaust treatment, complying with EU & global environmental standards for export inspection.
Standard Technical Specifications
| Model | Inner Chamber Size(Diameter×H,mm) | Installed Power(kW) | Max Loading Capacity(kg) |
| RN-35 | D350×450 | 23 | 80~120 |
| RN-45 | D400×600 | 45 | 120~250 |
| RN-65 | D450×900 | 67 | 300~380 |
| RN-95 | D600×1200 | 95 | 450~600 |
| Custom deep pit furnace: D300~D4000 available on request |
Main Product Advantages
1.Integrated process reduces production cost: No extra workpiece transferring or secondary loading, overall production cost 20% lower than separated nitriding & oxidation equipment.
2.Eco-friendly alternative to QPQ: Free of cyanide salt pollution; finished parts reach 300~500h salt spray resistance, surface hardness HV650~1100 with superior wear & anti-rust performance.
3.Low thermal deformation: All processes below 600℃, ideal for precision shafts, thin-wall parts and delicate molds with tiny distortion.
4.Low energy & ammonia consumption: Vacuum purging plus precise ammonia flow control reduces running cost for long-term production.
5.Multi-function machine: Support conventional nitriding, nitrocarburizing, steam blackening and low-temperature stress relief tempering.
Typical Application & Workpieces
1.Automotive parts: Crankshaft, engine valve, suspension pin, transmission gear, piston ring, hydraulic valve spool (45#,40Cr,42CrMo)
2.Mould industry: H13 die casting mold, plastic injection mold, stamping die, precision hardware die (3Cr2W8V,SKD61)
3.General machinery: Lead screw, hydraulic spool, valve fitting, bearing, high-strength fastener
4.Construction & wind power: Small gear ring, engineering machinery pin, pneumatic component parts
Standard Production Flow
Workpiece degreasing & cleaning → Hoist loading & furnace cover locking → Vacuum air replacement → Heat up to 530~560℃ & ammonia feeding for nitriding(6~24h as required) → Cool down to ~400℃ & stop ammonia supply → Feed pure water steam for in-situ post-oxidation(1~3h) → Furnace slow cooling below 200℃ → Discharge finished matte-black parts.
Energy Saving Pit Type Nitrocarburizing Furnace
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