Effect of Impact Angle on the Erosion–Corrosion Behavior of AISI 420 Stainless Steel in 3.5 wt.% NaCl Solution

Abstract

Erosion, erosion–corrosion, and synergistic behaviors of AISI 420 stainless steel were studied in 3.5 wt.% NaCl solution containing silica sand with the size of 250–500 μm as erodent particle. The erosion and erosion–corrosion tests were carried out according to ASTM G11909 standard and the synergism was calculated. The tests were performed using a slurry jet apparatus at a jet velocity of 6.5 m/s, sand concentration of 90 g/l, and various impinging angles of 20 deg–90 deg. Scanning electron microscope (SEM) was used to study the eroded surfaces and erosion mechanisms. The SEM images showed that under low impacting angles, cutting deformation was the main erosion mechanism while impact and work hardening could be responsible for material removal at high impacting angles. The results showed that the maximum erosion–corrosion and synergism rates occurred at an impingement angle of about 50 deg while the maximum pure erosion rate was obtained at impingement angle of about 35 deg. Energy dispersive spectrometry (EDS) analysis showed that an oxide layer was formed on the surfaces of the samples during erosion–corrosion tests. This oxide layer could make the surface more brittle and could lead to an increment of about 15 deg in the angle of the maximum removal rate. The formation and the subsequent removal of the nonprotective oxide layer as well as possible initiation and propagation of pits during erosion–corrosion tests could lead to higher erosion–corrosion rate compared to pure erosion resulting in a positive synergism under the conditions tested.

Effect of Equal Channel Angular Pressing (ECAP) on Erosion-Corrosion of Pure Copper

“…This result is consistent with the findings reported by the other previous studies [26]. It is reported that the maximum E-C rate were obtained with impact angle ranges from 30 • to 50 • for a range of materials such as pure iron, 304 stainless steel and aluminum [26][27][28][29]. The lowest values of weight loss due to E-C were recorded at an impacting angle of 90 • .…”

“…The previous researchers found that the material loss due to E-C is mainly affected by experiment duration, slurry flow velocity, impacting angle, erodent particle size, and solid particles concentration [27][28][29][30][31][32][33]. It is reported that the combined effect of erosion and corrosion together represents almost 40 -60% of the total weight loss [34].…”

Study of the pitting corrosion of superduplex stainless steel and X-65 carbon steel during erosion–corrosion by cyclic polarisation technique

“…[50][51][52] Corrosion pits were observed on the erosion-corrosion surfaces of various alloys. 8,14,27,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] Lopez et al 14 suggested the corrosion pits as the main degradation mechanisms during erosion-corrosion of AISI 304 and AISI 420 stainless steels in a slurry composed of 0.5 M H 2 SO 4 +3.5% NaCl and 30 wt-% quartz particles. Hu et al 27 observed corrosion pits on the eroded surface of API-5L-X65 in multi-phase jet impingement.…”

“…Corrosion pits were observed on the erosion–corrosion surfaces of various alloys. 8,14,27,43 -57 Lopez et al . 14 suggested the corrosion pits as the main degradation mechanisms during erosion–corrosion of AISI 304 and AISI 420 stainless steels in a slurry composed of 0.5 M H 2 SO 4 +3.5% NaCl and 30 wt-% quartz particles.…”