No abstract

No abstract

Austenitic stainless is having corrosion resistance property, but certain mechanical applications require improved resistance to wear, inferior cavitation, susceptibility to sensitization. These steels have numerous favourable circumstances for great cryogenic - properties, anti-corrosion, and bio-compatibility. So these steels have a broad application in low temperature innovation, saltwater applications, nourishment industry, bio-medicine, petro-chemical handling, and so forth when alloyed with nitrogen, austenitic treated steels has a progressively steady austenite structure, better mechanical properties and better wear opposition, which has animated extraordinary enthusiasm for this exploration work. Many surface hardening techniques are available, the best surface modification technique is chosen for improved service performance. Surface engineering is a technique to alter the surface of a material by mechanical or microchemical method without affecting the material properties. The alterations are done on the surfaces subjected to the liquid nitriding process to produce a hardened surface. Chosen for this research workbased on their wide application, the wear behaviour of AISI 316LN stainless steels was investigated. Of the various surface hardening techniques available, nitriding is chosen, so that these nitrogen gets penetrated into the material, in which hard iron chromium nitrides are formed at the surface level. AISI 316LN specimens were subjected to salt bath nitriding process. The specimens were nitrided to 60 minutes, 120 minutes and 180 minutes respectively. The specimens were undergone with wear tests by standardized tribiological wear machine and finally the metallographic studies were made.

Stainless steel is a popular material used in various industries due to its excellent corrosion resistance, high strength, and durability. Gas nitriding has been found significantly to improve wear resistance. Chosen for this research work AISI 304 were examined and the impact of gas nitriding to 12 hrs, 24 hrs and 36 hrs were analyzed for better wear behavior. To evaluate the tribological behavior, wear tests were carried out using pin on disc tribometer. The samples were undergone with hardness tests and the microstructures were examined through scanning electron microscope The difference between the compound layer and the diffusion layer were analyzed on the microstructure. The results of untreated samples and nitride samples were compared.

AISI 304 stainless steel categorized under austenitic, has good resistance to corrosion and applicable for high resistance to pitting and stresses. But it has poor hardness, sterngth and resistance to wear. In order to overcome the above problem, various hardening techniques like nitriding, carburizing, carbonitriding, Cyaniding etc are preferred. In this work, aqueous soluted nitriding process is carried out to improve the surface hardness and wear resistance on AISI 304 specimens. Three specimens in cylindrical shape with a diameter of 10mm and length 35mm are treated with salt bath nitriding process for a time period of 45 minutes, 90 minutes, 120 minutes and named as SBN 1, SBN 2, SBN 3 respectively. One specimen is kept untreated to compare the results with treated specimens. After the heat treatment procedure is completed, pin on disc wear testing instrument was used to conduct a wear test at a constant speed and load. All the specimens were subjected to Scanning Electron Microscope test and the results were compared.