Dear sir,
Here is some detail of the melonite operational process I hope it can be done in India also provided that if you go up-to the right door.
CENTRAL TOOL ROOM AND TRAINING CENTER (BHUBANESWAR)
CENTRAL INSTITUTE OF PLASTICS ENGINEERING AND TECHNOLOGY (GUINDY,CHENNAI)
JAMSHEDPUR MACHINE TOOLS LIMITED(JAMSHEDPUR)
The first ferritic nitro-carburizing methods were done at low temperatures, around 550 °C (1,022 °F), in a liquid salt bath. The first company to successfully commercialize was the Imperial Chemical Industries in England. They called their process a "Sulfinuz" treatment because it had sulfur in the salt bath. 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.[4]
Because of the cleaning issues the Joseph Lucas Limited company began experimenting with gaseous forms of ferritic nitrocarburizing in the late 1950s. The company applied for a patent by 1961. It produced a similar surface finish as the Sulfinuz process with the exception of the formation of sulfides. The atmosphere consisted of ammonia, hydrocarbon gases, and a small amount of other carbon-containing gases.[5]
This spurred the development of a more environmentally friendly salt bath process by the German company Degussa. Their process is the widely known Tufftride process. Following this the ion nitriding process was invented in the early 1980s. This process had faster cycle times, required less cleaning and preparation, formed deeper cases, and allowed for better control of the process.[6]
[edit] Process
Despite the naming the process is a modified form of nitriding and not carburizing. The shared attributes of this class of this process is the introduction of nitrogen and carbon in the ferritic state of the material. The processes are broken up into four main classes: gaseous, salt bath, ion or plasma, or fluidized-bed. The trade name and patented processes may vary slightly from the general description, but they are all a form of ferritic nitrocarburizing.[7]
[edit] Salt bath ferritic nitrocarburizing
Salt bath ferritic nitrocarburizing is also known as liquid ferritic nitrocarburizing or liquid nitrocarburizing[8] and is also known by the trademarked names Tufftride[2] and Tenifer.[9]
The most simple form of this process is encompassed by the trademarked Melonite process, also known as Meli 1. It is most commonly used on steels, sintered irons, and cast irons to lower friction and improve wear and corrosion resistance.[10][11]
The process uses a salt bath of alkali cyanate. This is contained in a steel pot that has an aeration system. The cyanate thermally reacts with the surface of the workpiece to form alkali carbonate. The bath is then treated to convert the carbonate back to a cyanate. The surface formed from the reaction has a compound layer and a diffusion layer. The compound layer consists of iron, nitrogen, and oxygen, is abrasion resistant, and stable at elevated temperatures. The diffusion layer contains nitrides and carbides. The surface hardness ranges from 800 to 1500 HV depending on the steel grade. This also inversely affects the depth of the case; i.e. a high carbon steel will form a hard, but shallow case.[10]
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. The intermediate quench is an oxidizing salt bath at 400 °C (752 °F). This quench is held for 5 to 20 minutes before final quenching to room temperature. This is done to minimize distortion and to destroy any lingering cyanates or cyanides left on the workpiece.[12]
Other trademarked processes are Sursulf and Tenoplus. Sursulf has a sulfur compound in the salt bath to create surface sulfides which creates porosity in the workpiece surface. This porosity is used to contain lubrication. Tenoplus is a two-stage high-temperature process. The first stage occurs at 625 °C (1,157 °F), while the second stage occurs at 580 °C (1,076 °F).[13]
[edit] Gaseous ferritic nitrocarburizing
Gaseous ferritic nitrocarburizing is also known as controlled nitrocarburizing, soft nitriding, and vacuum nitrocarburizing or by the tradenames Nitrotec, Nitemper, Deganit, Triniding, Nitroc, and Nitrowear.[2][14] 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.[15]
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. The actual gas mixtures are proprietary, but they usually contain ammonia and an endothermic gas.[15]
[edit] Uses
These processes are most commonly used on low-carbon, low-alloy steels, however they are also used on medium and high-carbon steels. Common applications include spindles, cams, gears, dies, and powdered metal components.[16]
Glock, an Austrian firearms manufacturer, utilizes the Tenifer process to protect the slides of the pistols they manufacture. The finish on a Glock is the third and final hardening process. It is 0.05 millimeters thick and produces a 64 Rockwell C (diamond cone) hardness rating via a 500 °C nitride bath. The final matte, non-glare finish meets or exceeds stainless steel specifications, is 85% more corrosion resistant than a hard chrome finish, and is 99.9% salt-water corrosion resistant. After the Tenifer process, a black Parkerized finish is applied and the slide is protected even if the finish were to wear off. Several other pistols also use this process including the Walther P99 and Steyr M/S series.[citation needed]
Grandpower, a Slovakian firearms producer, also uses a Tenifer IPQ treatment to harden metal parts on its K100 pistol
