3). In 2010 Glock switched to a gaseous ferritic nitrocarburizing process. Ferritic Nitrocarburizing in liquid salt bath Corrosion protection and wear resistance Meets or exceeds AMS 2753 Treatment Cycle Melonite-QPQ - SHOW - - HIDE - This complete process sequence is shown above and is in fact the QPQ®-process. While the process was very successful with high-speed spindles and cutting tools, there were issues with cleaning the solution off because it was not very water soluble. It produced a similar surface finish as the Sulfinuz process with the exception of the formation of sulfides. It is used to improve wear resistance and fatique strength of cast iron, sintered iron and steel. Ferritic Nitrocarburizing is the thermochemical process that simultaneously diffuses nitrogen and carbon into the surface of ferrous metals. The actual gas mixtures are proprietary, but they usually contain ammonia and an endothermic gas. Typically, this process involves either a salt bath nitriding or nitrocarburizing to properly treat a barrel. It is used to improve wear resistance and fatique strength of cast iron, sintered iron and steel. 2). The compound layer exhibits significant improvement in adhesive wear resistance. It is used as a post-nitride ‘quench bath.’ This neutralizes any potential toxic compounds which may have formed as a result of nitriding bath reactions reacting with any nitriding salt residues adhering to the components or fixtures.  In this technique intense electric fields are used to generate ionized molecules of the gas around the surface to diffuse the nitrogen and carbon into the workpiece. , The parts are first cleaned, usually with a vapor degreasing process, and then nitrocarburized around 570 °C (1,058 °F), with a process time that ranges from one to four hours. Liquid Salt Bath Ferritic Nitrocarburizing Non-Cyanide Bath(STABILIZED Jul 2019) AMS2753D This specification covers the requirements for an epsilon-iron nitride case on ferrous parts produced by immersion in a low-temperature, agitated, fused salt bath. Software Requirements: To view, complete, and print fillable PDF forms you'll need the freely available Adobe Reader software installed on your computer. a high carbon steel will form a hard, but shallow case. It has the added advantage of inducing little shape distortion during the hardening process. The bath is then treated to convert the carbonate back to a cyanate. When steel parts are placed into a preheated liquid salt, there is sufficient energy localized near the surface due to differences in chemical potential that then allows nitrogen and carbon species to diffuse from the salt into the steel substrate. In combination with oxidation bath it improves corrosion resistance and reduces surface roughness. It is most commonly used on steels, sintered irons, and cast irons to lower friction and improve wear and corrosion resistance. Despite the naming the process is a modified form of nitriding and not carburizing. What is the basic principle of Liquid Nitriding? The finish on a Glock pistol is the third and final hardening process. Common applications include spindles, cams, gears, dies, hydraulic piston rods, and powdered metal components. PVD High Energy Deposition Coating Technology, Chrome / Chromium Carbide Coating (CrC-TDH), Plasma Electrolytic Oxidation (PEO) | CeraTough™, Corrosion resistance exceeds chrome plating, Oil & gas components such as impellers, diffusers, and pipe and drill pieces (i.e. At this temperature steels and other ferrous alloys remain in the ferritic phase region. The process works to achieve the same result as the salt bath and gaseous process, except the reactivity of the media is not due to the temperature but to the gas ionized state. Such highly active gas with ionized molecules is called plasma, naming the technique. Version 9 or later of Adobe Reader is required. It is also known as Liquid/Salt Bath Ferritic Nitrocarburizing (FNC) process. The diffusion layer contains nitrides and carbides.  After the Tenifer process, a black Parkerized finish is applied and the slide is protected even if the finish were to wear off. , Plasma-assisted ferritic nitrocarburizing, Other trade names include Tuffride/ Tuffrider, QPQ, Sulfinuz, Sursulf, Meli 1, and Nitride, among others, https://www.youtube.com/watch?v=yt2DU-22qus, "To find the way in the nomenclature jungle of nitrogen diffusion", https://www.ahtcorp.com/services/nitriding-and-nitrocarburizing/ultraox/, MINIMIZING WEAR THROUGH COMBINED THERMO CHEMICAL AND PLASMA ACTIVATED DIFFUSION AND COATING PROCESSES by Thomas Mueller, Andreas Gebeshuber, Roland Kullmer, Christoph Lugmair, Stefan Perlot, Monika Stoiber, "Furnace Atmospheres 3: Nitrading and Nitrocarburizing", "Firearms History, Technology & Development", Tufftride-/QPQ-process: technical information, https://en.wikipedia.org/w/index.php?title=Ferritic_nitrocarburizing&oldid=995211950, Creative Commons Attribution-ShareAlike License, This page was last edited on 19 December 2020, at 20:51. , Despite the naming the process is a modified form of nitriding and not carburizing.  Besides Glock several other pistol manufacturers, including Smith & Wesson and Springfield Armory, Inc., also use ferritic nitrocarburizing for finishing parts like barrels and slides but they call it Melonite finish. salt bath nitriding equipment Since the introduction of salt bath nitriding (or ferritic nitrocarburizing) to North America in the 1950s, Kolene has been providing the necessary process equipment. , Plasma-assisted ferritic nitrocarburizing is also known as ion nitriding, plasma ion nitriding or glow-discharge nitriding.  The process works to achieve the same result as the salt bath process, except gaseous mixtures are used to diffuse the nitrogen and carbon into the workpiece. Modern salt-bath plant Nitrocarburizing offers an alternative to complicated coating processes and enables manufacturers to replace expensive materials with less costly ones. Heckler & Koch use a nitrocarburizing process they refer to as Hostile Environment. Salt Bath Nitriding/Nitrocarburizing is well known under various trade names, including ARCOR®, TENIFER®, TUFFTRIDE®, MELONITE®, and QPQ®. This process had faster cycle times, required less cleaning and preparation, formed deeper cases, and allowed for better control of the process. It is mandatory that the salt bath chemistry is checked at the commencement of each shift and the appropriate additions of salt are added to return the bath to its operational strength. Salt Bath Nitriding. Nitrocarburizing / Salt Bath Nitriding Ionic liquids offer a significant improvement in wear protection, sliding properties and fatigue strength on all kind of ferrous materials. Both types of nitrocarburization are used with steel and other iron alloy metals in a salt bath.  There are four main classes of ferritic nitrocarburizing: gaseous, salt bath, ion or plasma, and fluidized-bed. Due to the main process characteristics like It is 0.05 mm (0.0020 in) thick and produces a 64 Rockwell C hardness rating via a 500 °C (932 °F) nitride bath. Stainless steel workpieces can be processed at moderate temperatures (like 420 °C (788 °F)) without the formation of chromium nitride precipitates and hence maintaining their corrosion resistance properties.. This also inversely affects the depth of the case; i.e. Parts are typically core treated and finished machined prior to nitriding, with some allowance being made for a slight amount of growth. Houston Unlimited, Inc. offers a salt bath nitriding process, also referred to as liquid salt bath ferritic nitrocarburizing. The processing temperature ranges from 525 °C (977 °F) to 625 °C (1,157 °F), but usually occurs at 565 °C (1,049 °F). This quench is held for 5 to 20 minutes before final quenching to room temperature. , Salt bath ferritic nitrocarburizing is also known as liquid ferritic nitrocarburizing or liquid nitrocarburizing and is also known by the trademarked names Tufftride and Tenifer. A salt bath uses a liquid salt solution that is usually heated between 750 degrees Fahrenheit and 1050 degrees Fahrenheit. The surface formed from the reaction has a compound layer and a diffusion layer. An added benefit of the process is minimal distortion due to short process cycle within the ferrite phase. The processes are broken up into four main classes: gaseous, salt bath, ion or plasma, or fluidized-bed. Ferritic nitrocarburizing (FNC) is a thermochemical surface hardening process that involves diffusion of both nitrogen and carbon into the part. , The first ferritic nitrocarburizing methods were done at low temperatures, around 550 °C (1,022 °F), in a liquid salt bath. Salt Bath Nitriding is a ferritic nitrocarburizing process which involves the diffusional addition of both nitrogen and carbon to the ferrous surface at temperatures within the ferritic phase. A subsequent oxidizing quenching produce a major increase in corrosion resistance. The processes are broken up into four main classes: gaseous, salt bath, ion or plasma, or fluidized-bed. , This spurred the development of a more environmentally friendly salt bath process by the German company Degussa after acquiring ICI patents.  Since the introduction of the Glock pistol in 1982, this type of nitrocarburizing with postoxidation finish has become popular as a factory finish for military style handguns. Salt Bath Nitriding/Nitrocarburizing was originally created as an alternative to gas nitriding that would produce a more uniform case through surface contact between the substrate and liquid salt. During the process, a two-part surface layer is formed, an outer iron nitride layer with a nitrogen diffusion layer below it. , Glock Ges.m.b.H., an Austrian firearms manufacturer, utilized the Tenifer process until 2010, to protect the barrels and slides of the pistols they manufacture. , Other trademarked processes are Sursulf and Tenoplus. Due to the relatively low temperature range (420 °C (788 °F) to 580 °C (1,076 °F)) generally applied during plasma-assisted ferritic nitrocarburizing and gentle cooling in the furnace, the distortion of workpieces can be minimized. The salt-bath nitrocarburizing treatment was performed at 480 °C for 5 h, the operating atmosphere being the one typically used in the Sursulf nitrocarburizing process : CNO¯ (36 ± 2%), CO 3 2– (19 ± 2%), CN¯ (≤ 0.8%). 2. Despite the name, the process is really a modified form of nitriding with carbon added. Ferritic nitrocarburizing solves some of the problems of size change and distortion that are seen in higher temperature treatments. Salt Bath Basics. Post-oxidation after nitriding combined with polishing produces coatings with exceptional appearance (black color) and high corrosion resistance (greater than electrolytic chrome plating). Salt bath nitriding is a thermochemical process in which nitrogen and carbon are diffused simultaneously into the surface of the material. This is contained in a steel pot that has an aeration system. In combination with oxidation bath it improves corrosion resistance and reduces surface roughness. The gas used for plasma nitriding is usually pure nitrogen, since no spontaneous decomposition is needed (as is the case of gaseous ferritic nitrocarburizing with ammonia). It is a range of proprietary case hardening processes that diffuse nitrogen and carbon into ferrous metals at sub-critical temperatures during a salt bath. Salt-bath nitrocarburized steel, sintered iron and cast iron parts have very good wear, corrosion and fatigue resistance, as well as enhanced sliding proper-ties. Del-Quench™ Standard is a proprietary salt consisting of alkaline nitrate and hydroxide compounds. Salt Bath Nitriding/Nitrocarburizing was originally created as an alternative to gas nitriding that would produce a more uniform case through surface contact between the substrate and liquid salt. ISONITE® QPQ (per SAE AMS 2753) is a high-performance variety of salt bath nitrocarburizing process. The intermediate quench is an oxidizing salt bath at 400 °C (752 °F). , The simplest form of this process is encompassed by the trademarked Melonite process, also known as Meli 1. Liquid Nitriding / Salt Bath Nitriding (SBN) / QPQ /Ferritic Nitro-Carburizing (FNC) Liquid nitriding is a surface enhancement process with one of the longest track … The compound layer consists of iron, nitrogen, and oxygen, is abrasion resistant, and stable at elevated temperatures. The first stage occurs at 625 °C (1,157 °F), while the second stage occurs at 580 °C (1,076 °F). The shared attributes of this class of this process is the introduction of nitrogen and carbon in the ferritic state of the material. The trade name and patented processes may vary slightly from the general description, but they are all a form of ferritic nitrocarburizing. Grandpower, a Slovakian firearms producer, also uses a quench polish quench (QPQ) treatment to harden metal parts on its K100 pistols. This process is preferred for improving tribological and surface properties of ferrous components in addition to improving fatigue strength. The TENIFER process (TF1) is a salt bath nitrocarburizing of components in molten salt at temperatures around 580° C. Besides the addition of nitrogen, carbon also always diffuses into the surface in every TF1 treatment. In salt bath nitriding the nitrogen donating medium is a nitrogen-containing salt such as cyanide salt. The company applied for a patent by 1961. The trade name and patented processes may vary slightly from the general description, but they are all a form of ferritic nitrocarburizing. Other methods of ferric nitrocarburizing include gaseous process such as Nitrotec and ion (plasma) ones. drill heads), Treatment for mild steels, carbon steels, tool steels (A2, D2, M2, H13), and stainless steels (303, 304, 316), Development capabilities: specialty materials or components tailored to your specific application. It begins with the treating cycle of the nitrocarburizing segment, i.e. The first company to successfully commercialize the process was the Imperial Chemical Industries in Great Britain. , The process uses a salt bath of alkali cyanate. It is necessary to understand that there are two power-system types: continuous DC power a… An additional step can be added to the nitrocarburizing process called postoxidation. This is because of the low processing temperature, which reduces thermal shocks and avoids phase transitions in steel. This is a crucial reason for the positive, specific surface zone properties of salt bath … ICI called their process "the cassel" due to the plant where it was developed  or "Sulfinuz" treatment because it had sulfur in the salt bath. Nitrocarburizing and carbonitriding sound somewhat similar and they perform similar functions: to make a workpiece surface harder by imparting carbon, nitrogen or both to its surface. Tenoplus is a two-stage high-temperature process. Liquid Nitriding (LN) is a common term for a diffusion process that is actually liquid nitrocarburizing; a thermo-chemical reaction whereby nitrogen, primarily, and some carbon are diffused into the surface of iron-based materials. The atmosphere consisted of ammonia, hydrocarbon gases, and a small amount of other carbon-containing gases.