The processes are broken up into four main classes: gaseous, salt bath, ion or plasma, or fluidized-bed. Salt Bath Basics. Despite the name, the process is really a modified form of nitriding with carbon added. Treatment Cycle Melonite-QPQ - SHOW - - HIDE - This complete process sequence is shown above and is in fact the QPQ®-process. Houston Unlimited, Inc. offers a salt bath nitriding process, also referred to as liquid salt bath ferritic nitrocarburizing. The cyanate thermally reacts with the surface of the workpiece to form alkali carbonate. 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%). 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. The bath is then treated to convert the carbonate back to a cyanate. The process is carried out at 750-1050°F, making it faster than gas nitriding. The process is gaining a great deal of popularity in North America due to legislation on process effluents, European engineering specifications and a growing awareness of the process repeatability and metallurgical consistency due to computer control (Fig. [29] After the Tenifer process, a black Parkerized finish is applied and the slide is protected even if the finish were to wear off. 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. Grandpower, a Slovakian firearms producer, also uses a quench polish quench (QPQ) treatment to harden metal parts on its K100 pistols. Ferritic nitrocarburizing or FNC, also known by the proprietary names Tenifer, Tufftride and Melonite as well as ARCOR,[Note 1][1] is a range of proprietary case hardening processes that diffuse nitrogen and carbon into ferrous metals at sub-critical temperatures during a salt bath. [3][19] 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. Liquid Nitriding / Salt Bath Nitriding (SBN) / QPQ /Ferritic Nitro-Carburizing (FNC) Liquid nitriding is a surface enhancement process with one of the longest track … [14], A similar process is the trademarked Nu-Tride process, also known incorrectly as the Kolene process (which is actually the company's name), which includes a preheat and an intermediate quench cycle. 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. This porosity is used to contain lubrication. Salt Bath Nitriding. In salt bath nitriding the nitrogen donating medium is a nitrogen-containing salt such as cyanide salt. Ferritic nitrocarburizing solves some of the problems of size change and distortion that are seen in higher temperature treatments. Del-Quench™ Standard is a proprietary salt consisting of alkaline nitrate and hydroxide compounds. Besides, the process has few advantages, quick heating of the workpiece being the only one worth mentioning. To ensure part quality, our salt baths are continuously monitored, with chemistry adjustments made when necessary. This process is preferred for improving tribological and surface properties of ferrous components in addition to improving fatigue strength. The diffusion layer contains nitrides and carbides. [4], The first ferritic nitrocarburizing methods were done at low temperatures, around 550 °C (1,022 °F), in a liquid salt bath. It is used to improve wear resistance and fatique strength of cast iron, sintered iron and steel. Ion nitridingis also known as glow-discharge nitriding or plasma nitriding (Fig. 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. It begins with the treating cycle of the nitrocarburizing segment, i.e. [27], 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. [20], Plasma-assisted ferritic nitrocarburizing is also known as ion nitriding, plasma ion nitriding or glow-discharge nitriding. The compound layer consists of iron, nitrogen, and oxygen, is abrasion resistant, and stable at elevated temperatures. This is because of the low processing temperature, which reduces thermal shocks and avoids phase transitions in steel. 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. [17], Gaseous ferritic nitrocarburizing is also known as controlled nitrocarburizing, soft nitriding, and vacuum nitrocarburizing or by the tradenames UltraOx,[18] Nitrotec, Nitemper, Deganit, Triniding, Corr-I-Dur, Nitroc, NITREG-C and Nitrowear, Nitroneg. Nitrocarburizing / Salt Bath Nitriding Ionic liquids offer a significant improvement in wear protection, sliding properties and fatigue strength on all kind of ferrous materials. 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