A Broad Range of Applications for a Wide Range of Materials

  • No restrictions, nitriding iron based alloys ranging from mild steel to stainless steel and highly beneficial compound and diffusion zones for titanium and titanium alloys.
  • Abrasion resistant hard coatings
  • Both thermo-chemical and overlay coatings, produced during one combined heat treatment


Optimal Fatigue Strength


Compound Layer Free

Low Temperature treatment without loss of corrosion resistance for high chromium alloyed steels


Timing Gears



Depth >0, 4 mm

Valve Springs



Depth >0, 15 mm

Plate Springs



Depth >0, 15 mm




Depth 5-10 mm


Further Applications

  • Ejectors
  • Pison Rods
  • Valves
  • Cutting Tools
  • Stamping Tools/ Bending Tools
  • Punching Tools


Super Hardness


Compound Layer Free Plus PACVD

Cutting Tools



3 mmTIN

Forging Dies



4 mmTIN

Further Applications

  • Gears
  • Extrusion Dies
  • Aluminum Die Castings
  • Plastic Moulds


Ductile and Wear Resistant





Depth > 0, 25 mm

Extrusion Worms



Depth > 0, 5 mm




Depth > 0,5 mm

Aluminum Die Casting



Depth > 0,2 mm


Driving Mills



Depth > 0, 4 mm

Forging Tools



Depth > 0,2 mm

Plastic Moulds



Depth > 0,2


Further Applications

  • Aluminum Extrusion Dies
  • Slides
  • Tools
  • Pump Parts
  • Glass Moulds
  • Machine Parts


Wear and Corrosion Resistant


Automatic Gear Box



Compound Layer:

9 +/- 3 mm



Cast Iron, Surface Remelted

Compound Layer:

8-10 mm

Connecting Rods



Compound Layer:

10-15 mm

Piston Rods



Compound Layer:

> 10 mm

Gas Spring Tubes


Compound Layer:

5 mm



Further Applications

  • Guidings
  • Hydraulic Components
  • P/M Parts


Optimal Corrosion Resistance, Decorative




C 45

Compound Layer:

> 10 mm

Oxide Layer ca. 2 mm



Cast Iron

Compound Layer:

>10 mm

Oxide Layer ca. 2 mm




C 45

Compound Layer:

15-20 mm

Oxide Layer ca. 2 mm

Further Applications

  • Tool Holders
  • Hydraulic Components
  • Drills



Industries Served


High Performance Automotive: Nascar, Formula 1, and Indy


Surface hardening in all sectors of the metal industry

Surface hardening is required in many sectors of the metals industry for manufactured parts, and for production tooling.

Plasma nitriding can extend the operating life of many products by increasing their superficial hardness and wear resistance and by improving their corrosion resistance and fatigue strength. In fact, the successful application of many products is possible only after plasma nitriding.


Not Everything that hardens is good

Many older methods are suit being employed for surface hardening.  Some are better than others - but all methods have some distinct disadvantages.

  • Results are not always reproducible.
  • Compound zone chemistry is not controllable.
  • Critical work piece dimensions are changed.
  • Energy consumption is high.
  • Explosive gas mixtures are required.
  • Heat treatment materials are toxic.
  • The process is environmentally polluting.

Many manufacturers are forced to send their work to highly specialized commercial heat treaters because of these problems.


Plasma nitriding—a ray of hope

Very good results can be dependably obtained with plasma nitriding. The metallurgy of the hardened layers can be selected to consistently meet the requirements of any specific application. The equipment can operate at low energy levels, with inherently safe gas mixtures and without any danger of environmental pollution.

In spite of these important advantages there are still some operating considerations that have limited the general acceptance of this process. For example, the treatment temperature generally depends upon the proper selection of a large number of operating parameters like nitriding temperature and time, gas pressure and gas mixture composition and the plasma voltage. The proper arrangement of the work pieces within the furnace has required considerable operating experience. If the work pieces were not properly arranged, some surfaces were not nitrided or they may have been overheated.

Until recently, plasma nitriding has been a job for a few experts. Even with their specialized knowledge, they were not always able to avoid extended experiments to develop empirical processing data before they could reliably heat treat complicated work pieces.


ELTROPULS plasma nitriding process offers new possibilities

These problems have been overcome with the ELTROPULS plasma nitriding process. With this process, the range for application has been greatly enlarged and operating costs have been significantly reduced. ELTROPULS has been the right choice, even for small companies.


The ELTROPULS process offers you these important advantages for surface treatment.

  • Microprocessor control permits auto matic unattended operation.
  • The equipment operates without pollution and with no undesirable environmental impact.
  • The equipment makes no demand on plant utilities during idle periods.
  • The electrical energy, cooling water and process gas consumption are significantly lowered because of shorter treatment times.
  • Factory assembly of the equipment, with interconnecting wiring and piping, limits floor space requirements and reduces installation costs.

In a large forging plant, ELTROPULS plasma nitriding has been established as the standard treatment for dies.  A comparison with their previous salt bath operation showed a lot of new advantages.  The nitriding operation is less expensive and it is now environmentally friendly.  Die life has been increased by 70%.  The furnace is able to nitride up to 3000 lbs of these dies every day, on demand.


A wide range of permissible heat treating parameters reduces capital equipment costs

  • The composition and thickness of the compound zone are adjustable. The depth and hardness of the diffusion zone can be separately controlled. A wide range of treatment temperatures permits complete control over final metallurgical results.
  • A large variety of work geometries can be reproducibly treated without restrictive charging limitation. Treatment of a wide range of work sizes at one time, permits higher throughput and better equipment utilization.
  • There is no degradation of the work piece surfaces by arcing or overheating. Soft spots from insufficient plasma coverage are completely prevented. Areas that must not be treated are easily masked.
  • Tempering, stress relieving, aging and other heat treatments can be accomplished in the same furnace.

Advantages for your product

The ELTROPULS plasma nitriding process gives your product the surface layer it needs.

  • a mono phased, highly ductile gamma prime compound layer can be produced for high strength.
  • A relatively thick epsilon compound zone can be obtained for abrasive or corrosive application conditions.
  • The formation of a compound layer can be completely suppressed for work pieces subject to high dynamic stresses.
  • A wide variety of complex geometries including drills and reamers, punching, forging and extrusion dies, crankshafts and camshafts can be uniformly nitrided.
  • Chrome nickel steels can be nitrided without separate depassivation steps.
  • Changes in work dimensions and surface roughness are minimal and in most cases the work can be completely finished, at lower cost in its softer state, before nitriding.

Examples of successful applications of the ELTROPULS process

The ELTROPULS equipment is now used worldwide in the automotive, machine tool and manufacturing industries to improve surface characteristics, to solve application problems, to increase heat treating productivity and to reduce manufacturing costs. The examples below show just a few manufactured parts that are being routinely plasma nitrided.


Components of the ELTROPULS unit

  • An insulated, electrically heated furnace produces temperatures to 1200 F.
  • A mechanical pump produces vacuum levels between 50 microns and 5 torr.
  • A microprocessor, permits keyboard or menu process-parameter entry, controls the process and provides complete documentation.

Programming the ELTROPULS Microprocessor

Nitriding parameters, including temperature and time can be easily entered through the keyboard in response to clear-text prompts.  A variety of nitriding programs, either developed by the operator or supplied by ELTRO, can be permanently stored by the microprocessor.  The furnace operator can then start each nitriding program with a single pushbutton.


Operation of an ELTROPULS unit

The work pieces to be nitrided are either suspended from a fixture or placed directly on the furnace hearth.  The pumping system produces the programmed vacuum level and the work pieces are then heated to the proper temperature for surface treatment.  The gas composition, the gas pressure and the temperature determine what type of surface treatment will take place.

A pulsed voltage is applied between the work pieces and the furnace wall.  This voltage accelerates electrons to very high velocities (in this special case, very high velocities are functionally equivalent to very high temperatures) permitting them to ionize and activate normally inert gases like nitrogen so that the specified surface treatement can take place.  The high energy, but thermally low temperature, ionized gas mixture is called the plasma.  The high electron energy in the plasma permits physical and chemical reactions to take place that would normally require much higher surface temperatures.  The ELTROPULS system allows the temperature of the work pieces and the surrounding inert gas to remain relatively low during the entire surface treatment so the work pieces can retain their original core properties.







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