Accessing the full spectrum of corrosion behaviour of tempered type 420 stainless steel

Abstract

Bipolar electrochemistry produces a linear potential gradient between two feeder electrodes, providing access to the full spectrum of anodic-to-cathodic electrochemical behaviour. A type 420 martensitic stainless steel has been used to investigate microstructure evolution and corrosion behaviour with application of different tempering heat treatments. Tempering treatments at 250°C, 400°C and 700°C revealed the occurrence of pitting corrosion, with treatments at 550°C resulting in general and intergranular corrosion. Cr 23 C 6 was present in all tempering conditions, with Cr 7 C 3 and CrC only observed for tempering at 550°C. The 250°C tempering treatment had the highest corrosion resistance with a hardness value much higher than 500 HV.

Profile Characteristics and Evolution in Combined Laser and Electrochemical Machining

“…Compared with ECM, the surrounding machining area had some strip structures due to the increased inter-crystalline corrosion owing to the laser-enhanced electric current density. 26 Furthermore, in LSTEM, the materials in the side gap were removed by laserenhanced ECM, which could guarantee the high surface quality of the machined small holes.…”

A rapid corrosion screening technique for grade 2707 hyper‐duplex stainless steel at ambient temperature

“…[14,23] Bipolar electrochemistry offers a novel way to assess and rank both pit nucleation parameters and pit growth kinetics, detected on one sample from a single experiment. [23][24][25] In this manuscript, a standard three-electrode potentiodynamic corrosion test is compared to a traditional bipolar and modified bipolar electrochemistry experimental set-up to test HDSS 2707 at room temperature in 0.1 M HCl. The critical pitting potential and pit evolution in HDSS 2707 are investigated and compared via three-dimensional (3D) laser surface scanning confocal microscopy.…”

“…[ 14,23 ] Bipolar electrochemistry offers a novel way to assess and rank both pit nucleation parameters and pit growth kinetics, detected on one sample from a single experiment. [ 23‐25 ]…”

Application of bipolar electrochemistry to assess the ambient temperature corrosion resistance of solution annealed type 2205 duplex stainless steel

“…Bipolar electrochemistry was used to test the pitting corrosion resistance of type 2205 duplex stainless steel at room temperature and also used to research the relationship between the heat treatment and pitting corrosion for martensitic stainless steel [30,35]. In the work reported here, different solution annealing heat treatments for DSS 2205 are applied, to demonstrate application of bipolar electrochemistry to probe the localised corrosion resistance under a wide range of heat treatment conditions.…”