Pitting corrosion behaviour of stainless steel AISI 304 with different tinting colours

Ranganada Kasyap Pradeep Godavarthy Anantha Venkata, Bernadette Gsellmann, Rudolf Vallant, Christof Sommitsch

Research output: Chapter in Book/Report/Conference proceedingConference paper


Tinting colours are a problem often arising at the welding root surface of stainless steel pipes. They appear if a certain residual oxygen content is in the reducing N2/H2 purge gas. Different tinting colours are directly connectable to the thickness and the degradation of the chromium oxide layer. For the artificially produced different tinting colours in air, the reduction of the corrosion resistance is evaluated, to determine the critical residual oxygen content. The tinting colours show a change of the corrosion potentials. The investigations are conducted on the most common stainless steel type AISI 304 / 1.4301 of surface conditions 2B (Skin Pass) and 2R (Bright Annealed) with different tinting colours, artificially produced, using a furnace. Electrochemical linear polarization tests are performed on the tinted samples to investigate their corrosion resistance as a function of the Open Circuit Potential (OCP) and the Break Through Potential (BTP). Therefor a standard three electrode set up in a 1l corrosion cell with a 5% NaCl electrolyte is used. Furthermore, the investigations are aimed to standardize the corrosion testing procedure and parameter finding for future corrosion investigations on stainless steels for different applications depending on their surface condition. After the electrochemical tests the severity of the corrosion attack is evaluated metallographically by measuring the depth and the diameter of the pits.
Original languageEnglish
Title of host publicationESSC & DUPLEX 2017
Subtitle of host publication9th European Stainless Steel Conference - Science & Market / 5th European Duplex Stainless Steel Conference & Exhibition
Place of PublicationBergamo
Number of pages9
Publication statusPublished - 25 May 2017
EventESSC & DUPLEX 2017: 9th European Stainless Steel Conference - Science & Market / 5th European Duplex Stainless Steel Conference & Exhibition - Congress Center Giovanni XXIII , Bergamo, Italy
Duration: 25 May 201727 May 2017


ConferenceESSC & DUPLEX 2017
Abbreviated titleESSC 2017
Internet address


  • Stainless Steel – Corrosion resistance – Tinting – Linear Polarization – Pitting Corrosion

Fields of Expertise

  • Advanced Materials Science

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