Development and quality assessment of multi-point brazed diamond dressers produced by active brazing under high vacuum
- 95 Downloads
In the current work, multipoint single layer brazed diamond dressers were indigenously developed by high vacuum brazing technology using Ni-Cr and Ag-Cu-2Ti alloy. The vacuum level was maintained in the range of 10−6–10−7 mbar. To assess the quality, the developed dressers were subjected to eight dressing cycles with increasing grit penetration depth. The Ag-Cu-2Ti alloy, possessing a lower liquidus temperature of 820 °C, showed a superior grit retention ability compared to Ni-Cr alloy, having a higher liquidus temperature of 1050 °C. Higher thermal residual stresses developed in the case of Ni-Cr alloy, due to higher brazing temperature and difference in Young’s moduli and the coefficient of thermal expansion of the diamond grit, filler alloy, unfavorably led to the premature bond level failure of brazed diamond grit under lower specific loads. Elevated brazing temperature and formation of unfavorable intermetallic phases were found impairing the effectiveness of Ni-Cr alloy and caused severe graphitization of diamond. On the other hand, the silver-based bond experienced a potential threat of rapid wear by the hard bond-abrasive system of the grinding wheel during dressing. Localized “scooping” of bond material was observed in Ag-based bond layer securing diamond grits. Through a separate pin-on-disc test, it was demonstrated that this alloy received a substantial wear rate of 3.364 mm3/min and exhibited deterioration of frictional behavior, despite the presence of silver. The Ag-Cu-2Ti alloy with lower brazing temperature and lower tendency of graphitization has otherwise a more promising scope but only if the composition is suitably altered to bring in significantly higher abrasion resistance in its mechanical characteristics.
KeywordsMulti point diamond dresser Active brazing Bond strength Interfacial metallurgy Microstructure Abrasive resistance
Unable to display preview. Download preview PDF.
The authors would like to acknowledge the following organizations for their support: Department of Higher Education, Ministry of Human Resource Development, Government of India; Department of Science and Technology, Project No. MEE/13-14/315/DSTX/AMIA, Government of India; DST-FIST II, Project No. SR/FST/ET11-059/2013 (G), dated: 25-09-2014, Government of India and ElementsixTM, Em Pee Syndichem Pvt. Ltd., Mumbai, India.
- 1.Chattopadhyay AB Machining and machine tools. Wiley India Pvt LtdGoogle Scholar
- 2.Groover MP Grinding and other abrasive processes. In: Fundam. Mod. Manuf., Fourth. John Wiley & Sons, Inc., pp 604–627Google Scholar
- 3.Malkin S, Guo C Grinding mechanisms. In: Grind. Technol. Theory Appl. Mach., Second. Industrial Press, Inc., pp 115–156Google Scholar
- 9.Kühl CH Active Brazing of Diamonds – Technology and Application. 1–8Google Scholar
- 10.Andrews RM, Buljan S-T, Geary EG, et al (2014) Brazed diamond dressing toolGoogle Scholar
- 11.Lowder JT, Tausch EM (1977) Diamond abrasive toolGoogle Scholar
- 27.Schwartz MM, Aircraft S Fundamentals of brazing. In: ASM HANDBOOK, Welding, Brazing Solder. vol. 6. ASM International, pp 114–125Google Scholar
- 31.Yao Z-J, Su H-H, Fu Y-C, Xu H-J (2005) High temperature brazing of diamond tools. Trans Nonferrous Met Soc China English Ed 15:1297–1302Google Scholar
- 33.Ghosh A, Chattopadhyay AK (2007) On grit-failure of an indigenously developed single layer brazed CBN wheel. Ind Diam Rev 67:59–64Google Scholar
- 38.Miyoshi K (1998) Structures and mechanical properties of natural and synthetic diamonds. NASA TM-107249Google Scholar
- 39.Tanaka K, Hidaka K (1983) Hard facing nickel base alloyGoogle Scholar
- 42.Zmitrowicz A (2006) Wear patterns and laws of wear—a review. J Theor Appl Mech 44:219–253Google Scholar