Salts and equipments

Ionic liquids offer a significant improvement in wear protection, sliding properties and fatigue strength on all kind of ferrous materials. A subsequent oxidizing quenching produce a major increase in corrosion resistance. Due to the main process characteristics like:

• • excellent reproducibility on high quality level
  • shortest treatment times
  • most negligible distortion
  • highest flexibility
• • easy to handle

This technology gives often superior results to that of galvanic layers and other nitrocarburizing processes.

Salts for nitrocarburizing:

With TENIFER® / TUFFTRIDE® / MELONITE®  we offer a sustainable technology for nitrocarburizing. Following the principle of circular economy used Durferrit salts are recyclable.

*TF 1 = MEL 1 (available only in USA)

Additive salts for inert annealing; cyanide-free

Additive salts for preventing decarburation

Carburizing and carbonitriding salt melts feature following advantages:

• • best temperature uniformity
• • high reproducibility of the carburizing effect
• • easy to control
• • very flexible in use

The DUROFER® process is an environmental friendly process as the products do not contain any cyanide. The carbon activity is controlled by adding the regenerator CECONTROL®. Hence the amount of waste salt is considerably reduced. This technology can also be used for hardening being free of decarburization as long as the melt is set for low activity.

DUROFER® Process

Other salts for carburizing and carbonitriding

Boriding is a thermochemical diffusion process that gives components the following property improvements:

• • very high hardness up to 2000 Vickers
• • outstanding abrasive wear resistance
• • temperature strength up to 800 °C
• • strongly reduced sticking properties

Our boriding product produces a very good coating quality and prevents the unwanted formation of the very brittle FeB-phase.

Boriding products

The quality of solution annealing and age hardened aluminium and aluminium alloys increases strongly with temperature uniformity as well as with the speed of heat transfer. For this reason salt melts are the first choice.

They are well known for their excellent temperature constancy and provide the following benefits for the heat treatment:

• •  quickest heat transfer by contact which successfully limits grain growth creating a very fine core structure
• •  avoidance of deleterious precipitation of alloying elements on grain boundaries since the remaining salt film on the parts prevents critical cooling effects during transfer into quenching station
• •  shortest treatment times

Salts for the annealing of aluminium and aluminium alloys

Solvent based stop-off compounds

Kneadable stop-off compounds

Very often chemical processes take place in a closely defined and frequently very narrow temperature range. In industrial plants, salts are used as heat transfer media for heating and cooling as well as for holding at constant temperature.

Fields of Application

• •  heating of chemical reactors for endothermic processes
• •  for instance, the commercial syntheses in packed-bed tubular reactors for heterogeneous gas phase reactions.
• •  cooling of exothermal reactions for chemical syntheses processes
  •   the removed heat can be recovered.
• •   heat Storage in CPS Solar Power Plants for the time-delayed generation of electricity
• • drying of Gases
• •  heat Recovery
• •  general Heat Transfer in Process Engineering

Examples of Use

• •  production of phthalic acid (PAA) and maleic acid anhydride (MAA)
• •  production of acrylic acid as basic material for acrylates, coloring and super absorber materials
• •  production of methyl-methacryla tes as basic material for flat screens (sheets), acrylic glass and adhesives
• •  melamine syntheses
• •  hydrogenation and dehydrogenation of hydrocarbons
• •  polymerisation reactions

RUBBERCURE products are special designed heat transfer salts used with great success for the vulcanization of rubber profiles, which are for example continuously extruded. Some of their advantages are:

• •  high vulcanization speed
• •  compact profile surface without any porosity
• •  high long-term thermal stability of the salt melt
• •  excellent protection against corrosive attack
• •  rubber profiles are easy to clean

Very often chemical processes take place in a closely defined and frequently very narrow temperature range. In industrial plants, salts are used as heat transfer media for heating and cooling as well as for holding at constant temperature.

Fields of Application

• • Heating of chemical reactors for endothermic processes
  • For instance, the commercial syntheses in packed-bed tubular reactors for heterogeneous gas phase reactions.
• • Cooling of exothermal reactions for chemical syntheses processes
  • The removed heat can be recovered.
• • Heat Storage in CPS Solar Power Plants
  for the time-delayed generation of electricity
• • Drying of Gases
• • Heat Recovery
• • General Heat Transfer in Process Engineering

Examples of Use

• • Production of phthalic acid (PAA) and maleic acid anhydride (MAA)
• • Production of acrylic acid as basic material for acrylates, coloring and super absorber materials
• • Production of methyl-methacryla tes as basic material for flat screens (sheets), acrylic glass and adhesives
• • Melamine syntheses
• • Hydrogenation and dehydrogenation of hydrocarbons
• • Polymerisation reactions

Salt bath furnace for carburizing, hardening and annealing up to 950°C and quenching up to 650°C

Air pre-heater
Type LS / LSU
Salt bath for carburizing,
hardening and annealing
Type STC
Electrode furnace for carburizing,
hardening and annealing
Type SWCe
Salt bath for quenching and / or tempering
Type STQ, STA, STAQ, SWQ or SWA
Salt bath for austempering
Type SWZQ

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Salt bath furnace for salt reclamation

Salt reclamation furnace (up to 280°C)
Type SWV

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Salt bath furnace for steam tempering

Pit furnace for steam tempering tools
(up to 600°C)
Type DSU

Salt bath furnace for salt bath nitrocarburizing – CLIN^®-Processes

Air pre-heater
Type LS / LSU
Salt bath for nitrocarburizing
Type STT or STN
Salt bath for quenching and detoxification
Type STOX or SWQT

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Salt bath furnace for hardening and annealing
up to 1350°C

Electrode salt bath for hardening and annealing
Type STSe or SWSe

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Salt bath furnace for solution treatment of aluminium

Salt bath for solution treatment of aluminium
(up to 550°C)
Type SWAr

Salt bath furnaces for salt bath nitrocarburizing –
CLIN^®-Processes

gas-fired equipment is only offered
in exceptional cases

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Salt bath furnaces for salt reclamation

salt reclamation furnace up to (280°C)
Type SWVg or SWVrg

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Salt bath furnaces for carburizing, hardening and annealing up to 950°C and for quenching and tempering up to 650°C

Salt bath, type STCg, with or
without exhaust gas pre-heater
Type LSag

Circular or rectangular salt bath for
quenching and / or tempering
Type STQg, STAg, STAQg, SWQg or SWAg

Exhaust air cleaning plants

We design and supply suitable exhaust air cleaning plants depending on the process used in the heat treatment plant. These are usually dry filters or wet scrubber systems.

Evaporators

We supply electric or gas fired evaporators to eliminate waste water resulting in effluent-free heat treatment shops. Special models are available for water containing only AS140 salt.

Waste water holding tank

All waste water from hot water cascade wash systems type HWK, cold water quench tanks type ASB and wet scrubbers are discharged to the waste water holding tank type AWSB and then released at a controlled rate for subsequent treatment such as evaporation.

For cooling

Cold water tank for quench tank
Type ASB
Draining tank for cooling charge to room temperature
Type ATB
Air-cooling tank with blower
Type LAB 

For cleaning

Hot water cascade for washing components
Type HWK

For protection

Tanks for corrosion protection fluids and
dewatering fluids
Type IB or DFB

Solar Technology

Quench rate control for martempering baths – device MR97

The desired quench rate of AS140 marquench baths can be set and maintained by automatically monitoring and controlling the water content of the bath.

Control cubicles

Spare temperature control units for
existing furnaces are available.

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Charge documentation

Heat treatment process parameters
can be recorded and archived.

Solar Technology

We provide service engineers to repair and maintain existing Durferrit salt bath plants and we supply spare parts according to original drawings e.g.

• • Circular and rectangular pots of different sizes and material for all Durferrit salt bath processes
• • Brick linings for all furnace types
• • Electrodes, heating elements and replacement parts for gas burners
• • Furnace top plates and sealing material for pots
• • Thermocouples up to 1350°C

Please contact us for service of your plant or spare part orders:

Durferrit GmbH
Abteilung DTWS
Phone + 49 (0) 621 / 3 22 24-770
Fax + 49 (0) 621 / 3 22 24-870
E-mail: plant-department@hef-durferrit.com