Corrosion Fatigue Behavior of AISI 4340 Steel Coated With Cadmium and Zinc-Nickel With and Without Scribed Damage in Saltwater Environment

Riyadh A. Alzhrany

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Abstract

This research investigates the corrosion fatigue behavior of AISI 4340 high-strength steel coated with electroplated Cadmium and Zinc-Nickel in order to evaluate the possibilities of replacing Cadmium coating with Zinc-Nickel coating. Also, the research investigates the possibility of hydrogen re-embrittlement in the material after scribed damage in the coating layer. The specimens were tested under tension-tension fatigue conditions with a stress ratio of 0.1 and a load frequency of 10 Hz with and without scribed damage in coatings under a salt water environment. The salt water environment consisted of 3.5 wt. % Sodium Chloride at room temperature. The corrosion fatigue performance for Zinc-Nickel coated specimens with and without scribed damage was better than that of Cadmium coated specimens with and without scribed damage. There was no difference in the fatigue life between Zinc-Nickel coated specimens with and without scribe damage for both coatings. The scribed damage in Cadmium coated specimens and Zinc-Nickel coated specimens did not cause any obvious effect, such as hydrogen re-embrittlement.