Role of the material of contacting parts in the resistance of steel to corrosion-fatigue fracture

The corrosion-fatigue strength of steel specimens with press-fitted sleeves was studied. It was established that the reduction in the corrosion-fatigue strength of steel does not depend on the sleeve material.     

Effect of stress-raiser sharpness on corrosion-fatigue of steel specimens

The effect of notch sharpness and corrosive media on the fatigue of 5-mm-diameter steel specimens was studied. It was established that the influence of stress raisers in a corrosive medium is weaker than in atmospheric air, though this difference may disappear in the case of specimens with very sharp notches.     

Distinctive features of sulfide cracking of welded joints of pipe steel

We present the results of investigations aimed at the determination of susceptibility of welded joints in low-alloy 14GB pipe steel to sulfide cracking in the presence of technological defects. We established that these joints exhibit no susceptibility to cracking at stresses below −0.5σ_0.2 for the base metal, and thatK _Iscc in the NACE solution is equal to 28MPa√m. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 32, No. 6, pp. 104–106, November–December, 1996.     

Prediction of prestraining effect on fracture toughness of high strength structural steel by local approach

In the present study, the tension and fracture toughness tests on high strength structural steel of Q420 were carried out in different conditions of non-prestraining and prestraining. The results indicated that the prestrain increased the yield stress and tensile strength, but decreased the fracture toughness. Meanwhile, the local parameters m and σ_u controlling the brittle fracture were obtained using finite element method (FEM) analysis. Based on the Weibull stress fracture criterion, the prestraining effect on the fracture toughness was predicted from fracture toughness results of the virgin material by the local approach. The prediction was in good agreement with the experimental results. It certified that the critical Weibull stress obeys the two-parameter Weibull distribution in the local approach, and the fracture behaviour of the material with prestrain can be characterised well by the local approach.     

Effect of stress concentration on the corrosion-fatigue strength of iron and steel

The effect of stress raisers (0.6 mm diameter holes) on the corrosion-fatigue strength of armco iron and steel 50 plate in 0.01 N and 3% NaCl solutions was studied by tests on a base of 0.5·10⁶ cycles. A sharp reduction in the fatigue strength due to stress concentration was observed in the case of specimens tested in air, the effect of stress raisers in the case of specimens tested in corrosive media being less pronounced.