IADR Abstract Archives
Effect of Cobalt Chromium Alloy Reuse on its Microhardness using flame centrifuge casting method
Objectives: To measure the effect of adding 50wt% used alloy on its micro-Vickers hardness.
Methods: The total sample was divided into four groups (n=5) . Group 1 was the control with 100% fresh alloy exposed to flame centrifuge casting for the first time. Group 2, 3 and 4 had 50wt%t cut off of the previous castings. All specimens were cast using oxy acetyl flame and broken arm centrifuge casting machine. The samples were mount in clear acrylic and ground flat using emery paper. Final finishing was carried out using fine dimond past upto 0.25 micron. For microVicker’s hardness each specimen was indented thrice using a 500 gm force applied for 10 seconds (ASTM-E 384). One way ANOVA was used for comparision of means from the four groups.
Results: The group1 had the maximum mean hardness (340±10); followed by group 3 (334±10). Group 2 (305±11) and group 4 had the least values of micro hardness 303±15. The overall comperision of means amongest the four groups (F test when p=5%) for the micro Vicker’s hardness was non-significant (0.094).
Conclusions: within the limitations of the present study, it is recommended that commercial Co-Cr-Mo alloy can be re-used six times without affecting its Micro Hardness, when 50% fresh alloy is added on each re-use.
Methods: The total sample was divided into four groups (n=5) . Group 1 was the control with 100% fresh alloy exposed to flame centrifuge casting for the first time. Group 2, 3 and 4 had 50wt%t cut off of the previous castings. All specimens were cast using oxy acetyl flame and broken arm centrifuge casting machine. The samples were mount in clear acrylic and ground flat using emery paper. Final finishing was carried out using fine dimond past upto 0.25 micron. For microVicker’s hardness each specimen was indented thrice using a 500 gm force applied for 10 seconds (ASTM-E 384). One way ANOVA was used for comparision of means from the four groups.
Results: The group1 had the maximum mean hardness (340±10); followed by group 3 (334±10). Group 2 (305±11) and group 4 had the least values of micro hardness 303±15. The overall comperision of means amongest the four groups (F test when p=5%) for the micro Vicker’s hardness was non-significant (0.094).
Conclusions: within the limitations of the present study, it is recommended that commercial Co-Cr-Mo alloy can be re-used six times without affecting its Micro Hardness, when 50% fresh alloy is added on each re-use.
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