In this study, we designed and manufactured a large angular contact ball bearing (LACBB) with low deformation using JIS-SUJ2 steel and analyzed changes in its structural characteristics and chemical composition upon heat treatment. The bearing was produced by hot forging and heat treatment including a quenching and tempering (Q/T) process, and its properties were analyzed using 4 mm thick specimens. A difference in the size distribution of the carbide in the outer and inner parts of the bearing was observed and it was confirmed that large and non-uniform carbide was distributed in the inner part of the bearing. After heat treatment, the hardness value of the outer part increased from 13.4 HRC to 61 HRC and the inner part increased from 8.0 HRC to 59.7 HRC. As a result of X-ray diffraction (XRD) measurements, the volume fraction of the retained austenite contained in the outer part was calculated to be 3.5~4.8 % and the inner part was calculated to be 3.6~5.0 %. The surface chemical composition and the content of chemical bonds were quantified through X-ray photoelectron spectroscopy (XPS), and a decrease in C=C bonds and an increase in Fe-C bonds were confirmed.

1. 서 론
2. 실험 방법
    2.1. 시편준비
    2.2. 미세조직 관찰 및 경도시험
    2.3. 잔류 오스테나이트 측정
    2.4. 표면 화학조성 분석
3. 결과 및 고찰
    3.1. 미세조직 관찰 및 경도시험
    3.2. 잔류 오스테나이트 체적분율 측정
    3.3. 표면 화학조성 분석
4. 결 론
Acknowledgement
References
<저자소개>

• 이동희(단국대학교 파운드리공학과) | Donghee Lee (Department of Foundry Engineering, Dankook University, Youngin 16890, Republic of Korea)
• 조균택(한국생산기술연구원 동력소재부품연구그룹) | Kyun Taek Cho (Powertrain Materials and Components Research Group, Korea Institute of Industrial Technology, Suncheon 58022, Republic of Korea)
• 임현민(단국대학교 에너지공학과) | Hyeonmin Yim (Department of Energy Engineering, Dankook University, Cheonan 31110, Republic of Korea)
• 오승환(단국대학교 에너지공학과) | Seung-Hwan Oh (Department of Energy Engineering, Dankook University, Cheonan 31110, Republic of Korea)
• 김태범(한국생산기술연구원 친환경열표면처리연구부문) | Tae Bum Kim (Eco-friendly Heat Surface Treatment Research Division, Korea Institute of Industrial Technology, Siheung 15014, Republic of Korea) Corresponding author
• 김우병(단국대학교 파운드리공학과, 단국대학교 에너지공학과) | Woo-Byoung Kim (Department of Foundry Engineering, Dankook University, Youngin 16890, Republic of Korea, Department of Energy Engineering, Dankook University, Cheonan 31110, Republic of Korea) Corresponding author