Long‐term corrosion fatigue behaviour of structural materials

Abstract

In this paper, long‐term corrosion fatigue behaviour of structural materials such as 12Cr stainless steel and Ti−6Al−4V alloy for steam turbine moving blade and high‐strength steels for ship and offshore structures up to the ultrasonic frequencies is reviewed mainly on the basis of the author's experimental results. The emphasis is focused upon the corrosion fatigue behaviour of 12Cr stainless steel in NaCl and NaOH aqueous solutions. It is shown that the corrosion fatigue strength of 12Cr stainless steel is strongly dependent on NaCl content in aqueous solution. It is also exemplified that the ultrasonic corrosion fatigue strength of 12Cr stainless steel decreases remarkably if an aggressive environment like 40% NaOH aqueous solution should be formed at the crack bottom even in a dilute NaOH aqueous solution.

Experimental study on very high cycle fatigue of martensitic steel of 2Cr13 under corrosive environment

“…AISI4340 in distilled water and 40Cr in 3.5% NaCl exhibited a continuously decreasing S–N curve till 10 8 cycles, indicating the elimination of fatigue limit strength in corrosive environment. The fatigue limit of 12Cr stainless steel existed in mild solution of NaOH but disappeared as solution concentration increased from 5% to 40% . The same tendency was seen in 40Cr that there is a fatigue limit in water but is eliminated in 3.5% NaCl .…”

“…In corrosion fatigue, materials, environment and mechanical loading interact in a complex way and whether a fatigue limit exists strongly depends on the specific corrosive solution and material. Ebara's work on fatigue and corrosion fatigue of steam turbine material of 13Cr stainless steel gave a good verification. For comparison, the testing results from Ebara's work were plotted together with the present data, as shown in Fig.…”

“…However, the conventional design and life evaluation are based on S-N data below10 7 cycles, and so far, it has only a few reports on very high cycle fatigue of 2Cr13 in corrosive environment. 38,40 Therefore, it is necessary to investigate this important issue. In this paper, rotating bending fatigue test at very high cycle region was carried out on 2Cr13 in both air and 3.5% NaCl to investigate the effect of corrosive environment on fatigue responses in high and very high cycle regions.…”

Measurement and prediction of CTOD in austenitic stainless steel

“…A potential application for the JWES strain hardening modification can occur when stainless steel is used. Austenitic stainless steel is often used in harsh environments because of its corrosion resistance properties . When compared to typical structural and high strength steel, austenitic stainless steel can have significantly higher strain hardening, which is a result of its high ductility.…”

“…Austenitic stainless steel is often used in harsh environments because of its corrosion resistance properties. [19][20][21][22] When compared to typical structural and high strength steel, austenitic stainless steel can have significantly higher strain hardening, which is a result of its high ductility. This ductility usually implies better fracture toughness properties, which in turn leads to reduced engineering safety concerns, but it is still important that this design criterion is assessed.…”