TY - GEN
T1 - Grinding induced changes in residual stresses of carburized gears
AU - LeMaster, R.
AU - Boggs, B.
AU - Bunn, J.
AU - Hubbard, C.
AU - Watkins, T.
PY - 2007
Y1 - 2007
N2 - Carburizing is a commonly used method for increasing the strength and wear resistance of gearing. A significant benefit of the carburization process is that compressive residual stresses are developed near the surface due to phase transformations that occur during the post carburization heat treatment steps. After carburization and heat treatment it is necessary to finish the gear by processes such as grinding or skiving. These finishing processes develop the precise geometric form required while improving the surface finish. Finishing processes change the residual stress imparted by carburization and subsequent heat treatment. Residual stresses change during the finishing process due to the removal of material and stresses induced from the machining operation. This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory. Two of the gears were hobbed, carburized, quenched and tempered, but not finished. The remaining three gears were processed similarly, but were finish ground. The residual stresses were measured at 64 different locations on a tooth from each gear. Residual stresses were also measured at fewer points on other teeth to determine the tooth-to-tooth variation. Tooth profile measurements were also made of the finished and unfinished gear samples. The results show a fairly uniform and constant compressive residual field in the nonfinished gears. There was a significant reduction in the average residual stress measured in the finished gears. Additionally, there was a significant increase in the variability of the residual stress that was introduced by the grinding process. Large variations were observed in both the lateral and longitudinal directions on a tooth surface. Analysis of the data suggests a linear relationship between the change in average residual stress and the amount of material removed by the grinding process.
AB - Carburizing is a commonly used method for increasing the strength and wear resistance of gearing. A significant benefit of the carburization process is that compressive residual stresses are developed near the surface due to phase transformations that occur during the post carburization heat treatment steps. After carburization and heat treatment it is necessary to finish the gear by processes such as grinding or skiving. These finishing processes develop the precise geometric form required while improving the surface finish. Finishing processes change the residual stress imparted by carburization and subsequent heat treatment. Residual stresses change during the finishing process due to the removal of material and stresses induced from the machining operation. This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory. Two of the gears were hobbed, carburized, quenched and tempered, but not finished. The remaining three gears were processed similarly, but were finish ground. The residual stresses were measured at 64 different locations on a tooth from each gear. Residual stresses were also measured at fewer points on other teeth to determine the tooth-to-tooth variation. Tooth profile measurements were also made of the finished and unfinished gear samples. The results show a fairly uniform and constant compressive residual field in the nonfinished gears. There was a significant reduction in the average residual stress measured in the finished gears. Additionally, there was a significant increase in the variability of the residual stress that was introduced by the grinding process. Large variations were observed in both the lateral and longitudinal directions on a tooth surface. Analysis of the data suggests a linear relationship between the change in average residual stress and the amount of material removed by the grinding process.
UR - http://www.scopus.com/inward/record.url?scp=49549100859&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:49549100859
SN - 9781604238624
T3 - American Gear Manufacturers Association - Fall Technical Meeting of the American Gear Manufacturers Association 2007, AGMA
SP - 65
EP - 80
BT - American Gear Manufacturers Association - Fall Technical Meeting of the American Gear Manufacturers Association 2007
T2 - Fall Technical Meeting of the American Gear Manufacturers Association 2007
Y2 - 7 October 2007 through 9 October 2007
ER -