A Study on the Fracture Surface Growth Behavior of Steel used for Frame of Vehicles by Corrosion Fatigue

자동차 프레임용 강재의 부식피로에 의한 파면성장거동에 관한 연구

  • Lee, Sang-Yoel (Dept.of Automobile,Pohang college) ;
  • Im, Jong-Mun (Dept.of Automobile,Pohang college) ;
  • Im, U-Jo (Dept.of Mechanical Eng, National Fisheries University of Pusan) ;
  • Lee, Jong-Rak (Dept. of Mechanical Eng.,National Fisheries University of Pusan)
  • Published : 1992.03.01


In this study, corrosion fatigue test of SAPH45 steel was performed by the use of plane bending fatigue tester in marine environment and investigated fracture surface growth behavior of base metal and heat affected zone corrosion fatigue. The main results obtained are as follows: 1) Fracture surface growth of heat affected zone (HAZ) is delayed more than that of base matel (BM), and they tend to faster in seawater than in air. 2) Corrosion sensitivity to corrosion fatigue life of HAZ is more susceptible than that of BM. 3)In the case of the corner crack by corrosion fatigue, the correlation between the propagation rate of fracture surface area(dA/dN) and stress intensity factor range(ΔK) for SAPH45 are applied to Paris rule as follows: dA/dN=C(ΔK) super(m) where m is the slope of the correlation, and is about 6.60-6.95 in air and about 6.33-6.41 in seawater respectively.