Abstract
Corrosion fatigue tests of 13Cr martensitic stainless steels in several tempered states were carried out in 3% NaCl solution at room temperature, and the effect of metallurgical variables on corrosion fatigue strength at 107109 cycles was investigated. The followings are found : 1) Corrosion fatigue strength σWC monotonically decreases with the loading cycle. At 109 cycles, σWC decreases to 50MPa for some tempered states. 2) In a high cycle region, σWC strongly depends on the tempering conditions, and σWC of the steels sensitive to intergranular corrosion was relatively low because of the formation of deep pits. 3) The apparent stress intensity factor for corrosion fatigue cracking, Kcf, is about 1.62.5MPa√m at 107109 cycles and independent of tempering conditions. 4) The rate determining process for corrosion fatigue life under high cycle and low stress conditions appears to be that of pitting corrosion. 5) One of the effective methods to increase corrosion fatigue strength may be careful selection of the tempering conditions in which the Cr depleted zone is not formed.
