Author/Authors :
SUBAŞI, Mehmet Gazi Üniversitesi - Atatürk Meslek Yüksekokulu, Turkey , KARATAŞ, Çetin Gazi Üniversitesi - Teknik Eğitim Fakültesi - İmalat Mühendisliği Bölümü, Turkey
Abstract :
In this study, primarily some specimens of AISI 4140 steel with initial hardness of 12 HRC have been treated to reach the 40, 45, 50 HRC hardness values and then the amount of residual stresses on the hardened specimens was measured. In this study, for reaching to the different hardness values, the specimens were cooled in oil medium after waiting at 930 C for 1 hour. The speciment were tempered at 427 0C, 316 0C, 204 0C for 40 minutes, consequently reaching the hardness of 40, 45, 50 HRC respectively. Residual stresses in heat treated specimens were determined by the layer removal method. As a result of the experiments, the tensile residual stress on the surface of not heat-treated specimen (12 HRC) was 211 MPa. On the other hand, the tensile residual stress on the surface of heat-treated ones with 40, 45, 50 HRC hardness values, were found as 169, 299, 203 MPa respectively. Finally, this study has shown that the residual tensile stresses on the surface of the material were due to hardening and the values of the residual stresses are affected by the hardness amount of materials.
