KorroPad testing - applications from industry and research

Abstract

The pitting corrosion resistance of stainless steels can be assessed with the KorroPad test in a very simple, quick and inexpensive way. The KorroPad is therefore an interesting alternative to time-consuming long-term tests and complex electrochemical investigations for manufacturers, processors and users of stainless steels. In this article, the basic functionality of the KorroPad is described and selected examples from industry and research illustrate it´s application. The assessment of grinding processes and post-weld treatment are first presented as relevant examples regarding industrial surface treatments on the pitting corrosion resistance. Subsequently, current research to the modification of the KorroPad test is presented, which shows the specific detection limit of KorroPads on binary Fe-Cr reference alloys. Finally, modified KorroPads are used to detect microstructure related susceptibility to pitting corrosion induced by sensitizing heat treatment. The KorroPad enables the creation of a sensitization T-t diagram based on the pitting corrosion resistance.

Application limits and sensitisation behaviour of the manganese‐ and nitrogen‐alloyed austenitic stainless steel P2000 (X13CrMnMoN18‐14‐3)

“…First invented in 2014, this relatively new method has been successfully used for this purpose on stainless austenitic, martensitic and duplex steels. [ 14,15,29–32 ] During the preparation process, the samples were wet‐ground with 180‐grit SiC paper, cleaned, dried in warm air and passivated at more than 95% relative humidity. For the experiment, KorroPads with a composition of 0.1 M NaCl and 1 mM K 3 [Fe(CN) 6 ] and a diameter of 20 mm were placed on the surface for 15 min.…”