Salt
Molten Salt Solutions for Precise, Uniform Heat and Surface Treatments
Advanced Surface Engineering Through Thermal Salt Baths
In industrial applications, “salt” refers to specially formulated chemical compounds used in molten form to conduct heat treatment or thermochemical processes. These molten salts provide uniform, controlled heating and enable controlled oxidation (such as black magnetite formation for corrosion resistance and aesthetic finishes). They also facilitate precise thermal or chemical surface treatments, including nitriding, carburizing, and annealing. Their high thermal stability and excellent heat transfer properties make them ideal for processes that require rapid, consistent temperature control across complex geometries.
Nitrocarburizing
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 often gives 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.
Carburizing and Carbonitriding
Carburizing and carbonitriding salt melts feature the following advantages:
- Best temperature uniformity
- High reproducibility of the carburizing effect
- Easy to control
- Very flexible in use
The DUROFER® process is an environmentally 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
Products Application Working temp. in °C CECONTROL® Regenerator; for use only with the base salts CECONTROL® 50 H, 80 B und 110 B CECONTROL® 50 H Cyanide-free starter and replenishment salt to achieve a surface carbon level of approx. 0.5 % C; for use only with CECONTROL® regenerator 780 – 950 CECONTROL® 80 B
CECONTROL® 110 BCyanide-free starter and replenishment salt to achieve a surface carbon level of approx. 0.8 resp. 1.1% C; for use only with CECONTROL® regenerator 820 – 950 Other salts for carburizing and carbonitriding
Products Application Working temp. in °C CECONSTANT® 80
CECONSTANT® 110One-salt system to achieve a surface carbon level of approx. 0.8 % C resp. 1.1 % C 850 – 950 CECONSTANT® 80 A
CECONSTANT® 110 AStarter salts for the initial filling GS 540 / C 3 This two-salt system is also suitable for carbonitriding below A1. 700 – 950 Aluminum Heat Treatment
The quality of solution annealing and age-hardened aluminum and aluminum 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 the quenching station
- shortest treatment times
Salts for the annealing of aluminum and aluminum alloys
Products Application Working temp. in °C AVS 220 For solution annealing and age hardening of aluminum and aluminum alloys containing maximal 10% of magnesium. 270 – 550 AVS 250 For solution annealing and age hardening of aluminum and aluminum alloys containing maximal 10% of magnesium. 40 – 550 Stop-Offs Compounds
Products Application CONTRADUR WSC 200 Silicate free compound for gas carburizing up to 1.3 mm; applicable by painting; easy removable with hot water or alkaline cleaner CONTRADUR WSC 201 Silicate free compound for gas carburizing up to 1 mm; applicable by dipping; easy removable with hot water or alkaline cleaner WAGA For gas carburizing for more than 1.3 mm case depth; applicable by painting or dipping WAGA Plus For gas carburizing for more than 1.3 mm case depth; favorable at higher humidity; applicable by painting ANTIDUR For gas carburizing for more than 1.3 mm case depth; applicable by dipping CONTRADUR WSN 100 For gas nitriding and nitrocarburizing; applicable by painting Solvent Based Products Application CONTRADUR GAKO For gas carburizing up to 1.3 mm case depth; applicable by painting or dipping S100 For gas and powder nitriding and gas nitrocarburizing; applicable by painting THINNER I Thinner for CONTRADUR GAKO and S100 Kneadable Products Application ATOMIN For pack carburizing and sealing hardening boxes; easy kneadable and removable; esp. for small holes, threads, etc REKORD For pack carburizing and sealing hardening boxes; little shrinking properties; favorable for larger areas or pin holes TENIFER™ / TUFFTRIDE™ / MELONITE™ Process
Products Application Working temp. in °C TF 1* Base nitriding salt, for use only with REG 1 regenerator 480 – 630 REG 1 Polymeric regenerator for nitriding salt TF 1 AB 1 Oxidizing salts for enhancing the corrosion resistance of treated components in TF1 baths and for QPQ process TF-N Improved base nitriding salt for gaining very compact layers, for use only with REG-N regenerator 480 – 630 REG-N Polymeric regenerator for TF-N baths AB-N Oxidizing salts for enhancing the corrosion resistance of treated components in TF-N baths and for QPQ process *TF 1 = MEL 1 (available only in USA)
Boriding
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.
Products Application Working temp. in °C DURBORID®G Granules that create perfectly formed boride layers for maximum performance; the work pieces can be easily removed after treatment 850 –1000 Heat Treatment of High-Speed Steel
Products Application Working temp. in °C GS 540 Salt for the 2nd preheating stage 800 – 950 GS750/R2 2-salt systems for the 3rd preheating stage 1050 – 1100 CARBONEUTRAL™ For austenitizing of high alloyed tool and high-speed steels. Additives are reducing decarburization. 1000 – 1300 SEMPERNEUTRAL™ 950 For austenitizing of high alloyed tools and high-speed steels. Additives prevent from decarburization. 1100 – 1300 SEMPERNEUTRAL™ 1100 For austenitizing of high-speed steels. Additives prevent from decarburization. Less sensitive to moisture. 1200 – 1300 GS 430 Quenching salt for high alloyed tool and high speed steels. 500 –600 DUROPERL For covering the CARBONEUTRAL or SEMPERNEUTRAL baths. SILIRON HS Additive to accelerate the subsequent aqueous cleaning. GS 960 For saturating a new lining of the furnace. Annealing and Hardening
Products Application Working temp. in °C GS 230 For quenching and tempering above 300°C 300 – 600 GS 430 For tempering, heating and quenching of steel for which AS bathes are not suitable. 500 – 700 GS 520 Replenisher salt for GS 430 baths. GS 540 For heating and annealing. 600 – 950 GS 560 Nontoxic salt for annealing silver, gold and brass. 600 – 850 GS 660 Nontoxic salt for annealing steel and non-ferrous metals. 750 – 900 GS 670 For heating and annealing 750 – 1000 GS 750 For heating and annealing. 850 – 1100 GS 960 For heating and annealing. 1050 – 1250 Additive salts for inert annealing; cyanide-free
Products Application R 2 For the prevention of decarburization and oxidation in combination with GS 430, GS 540, GS 670, GS 750 R 3 Nontoxic additive for the prevention of decarburization and oxidation in combination with GS 660. Additive salts for preventing decarburation
Products Application C 1 For the prevention of decarburization and oxidation in combination with GS 540, GS 560, GS 660, GS 670, if the carbon content of C 3 is undesirable. C 3 For the prevention of decarburization and oxidation in combination with GS 540, GS 560, GS 660, GS 670. Contains active carbon to form a bath cover. Blackening
Products Application Working temp. in °C G19 / G22 Alkaline cleaner for hot degreasing prior to blackening 60 – 80 BEIZENTFETTER For descaling prior to blackening. Has some degreasing properties. RT FERROBLACK™MH Blackening salt containing special additives for a wide range of application. 140 approx. FERROBLACK™ HL Particularly suitable for parts with copper coatings and brazed joints 140 approx. STREICH-BRÜNIERBEIZE A fluid product for brushing on or immersion at room temperature. Ideal for repairs and hobby use. Quenching and Tempering
Products Application Working temp. in °C AS 140 For austempering, martempering, tempering and blueing. Not suitable for components which are heated above 950 °C or treated in a bath containing more than 13 % KCN. 170– 550 AS 220 For austempering, martempering, tempering and blueing. Not suitable for components which are heated above 950 °C or treated in a bath containing more than 13 % KCN. 250 – 550 AS 235 Non toxic salt for austempering, martempering, tempering and blueing. Not suitable for components which are heated above 950 °C or treated in a bath containing more than 13 % KCN. 280 – 550 AS 300 Non toxic salt for austempering, tempering and blueing. Not suitable for components which are heated above 950 °C or treated in a bath containing more than 13 % KCN. 340 – 550 GS 230 For quenching and tempering parts at temperatures above 300 °C. 300 – 600 GS 430 For quenching and tempering parts which are austenitized at temperatures above 950 °C. 500 – 600
Heat Transfer Salts
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
Products Application Working temp. in °C ASD Heat transfer salt for the chemical industry. 180 – 450 ASD REG For regenerating ASD salts. Vulcanization
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
Products Application Working temp. in °C RUBBERCURE For vulcanizing in LCM and PLCV plants. > 180 RUBBERCURE LAS Nitrite-free vulcanizing salt > 160 Salts for Heat Transfer in Chemical Reactors
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
Products Application Working temp. in °C ASD Heat transfer salt for the chemical industry. 180 – 450 ASD REG For regenerating ASD salts.