1. PREPARED BY: AKASH CHAUDHARY III YEAR, MECHANICAL ENGINEERING ROLL NO: 1004340002

2. WHAT IS WEAR? HARMFUL EFFECTS :  Causes failure of machines  Reduces efficiency of machine parts  Significant maintenance  Heavy replacement costs  Leads to increase in clearances Progressive loss of material

3.  Adhesive wear  Abrasive wear  Fatigue wear  Corrosive wear

4. LIMITS INDUSTRIAL PRODUCTIVITY AND ECONOMIC PROGRESS

5. 1. CRYOGENIC HEAT TREATMENT extremely low temperature processing of materials 2. CARBURIZING Diffusion of carbon into the material. Temperature range from 850 o -970 o C [4] Increases hardness of the surface High grade steels can be formed

6. 3. NITRIDING Heat treatment process Enriching the surface with the nitrogen Conducted mainly between 450 o -620 o C [4] Formation of nitrogen compounds with iron and alloying elements like Al or Cr

7. 4. CARBONITRIDING Inclusion of a nitrogen component in the form of ammonia Economical than carburizing Conducted at lower temperatures Increased resistance to quenching distortion

8. 5. COATING TECHNIQUES [3] Surface is coated to increase life Coated surfaces are more resistant to chemically active environment Abrasive wear is less Alumina ceramics, metal nitrides etc are used as coating materials

9. Ultra low temperature process (even below 77K ) Improves wear resistance and hardness of tool steels It is not a surface treatment Retained austenite is transformed to martensite Capable of treating ferrous and non ferrous metals, alloys, carbides, plastics

10. Carried out inside a well insulated chamber. Fig. 1. A cryogenic chamber[1]

11. Ultra cold temperatures are achieved using computer controls Dimensional changes are taken care off well Liquid nitrogen is used for the purpose Takes about 36 - 74 hours

12. This experiment conducts an “ Abrasive wear test ’’ on various materials. Fig. 2. Abrasive wear test apparatus[6]

14. Samples used in the experiment are cylindrical having a diameter of 12.7 mm and a length of 64 mm Three sets of the samples were used : Sample which was not given any cryogenic treatment after the usual heat treatment. Set I Sample which was given same heat treatment and then cooled from room temperature to 189 K Set II Sample which was given same heat treatment and then cooled from room temperature to 77 K Set III

15. Each of the sample was abraded for 15 minutes intervals Between each wear period, the sample was removed from the wear apparatus and weighed to determine the mass removed by wear. Total run time for the majority of the samples was 75 min

17. Give better results over conventional heat treatment processes Cryotreatment - an extension of heat treatment Cryo-treatment affects steels differently, when proper heat treatment is combined with the correct cryo process The process is completely environment friendly Helps reduce waste Capable of treating a wide variety of materials

18. 1..Surface Engineering for Corrosion and Wear Resistance, ASM International,2001 2. http://textbooks.elsevier.com/manualsprotectedtextbooks/97807506 63809/Static/wear 3. Holmberg K., Matthews A., Coating Tribology, Elsevier, Amsterdam, 1994. 4. http://nitrex.com/english/technologies_modern.htm 5. http://www.stle.org/resources/lubelearn/wear/default.aspx 6. Barron, R.F., “Cryogenic treatment of metals to improve wear resistance”, CRYOGENICS, August 1982

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