The effect of build direction and heat treatment on atmospheric stress corrosion cracking of laser powder bed fusion 316L austenitic stainless steel

2021 ◽  
Vol 40 ◽  
pp. 101902
Author(s):  
P. Dong ◽  
F. Vecchiato ◽  
Z. Yang ◽  
P.A. Hooper ◽  
M.R. Wenman
2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Alberto Sáez-Maderuelo ◽  
Dolores Gómez-Briceño ◽  
César Maffiotte

The supercritical water reactor (SCWR) is one of the Generation IV designs. The SCWR is characterized by its high efficiency, low waste production, and simple design. Despite the suitable properties of supercritical water as a coolant, its physicochemical properties change sharply with pressure and temperature in the supercritical region. For this reason, there are many doubts about how changes in these variables affect the behavior of the materials to general corrosion or to specific types of corrosion such as stress corrosion cracking (SCC). Austenitic stainless steels are candidate materials to build the SCWR due to their optimum behavior in the light water reactors (LWRs). Nevertheless, their behavior under the SCWR conditions is not well known. First, the objective of this work was to study the SCC behavior of austenitic stainless steel 316 type L in deaerated supercritical water at 400°C/25  MPa and 30 MPa and 500°C/25  MPa to determine how variations in pressure and temperature influence its behavior with regard to SCC and to make progress in the understanding of mechanisms involved in SCC processes in this environment. Second, the oxide layer formed at 400°C/30  MPa/<10  ppb O2 was analyzed to gain some insight into these processes.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 327
Author(s):  
Arshad Yazdanpanah ◽  
Mattia Lago ◽  
Claudio Gennari ◽  
Manuele Dabalà

Surface quality and dimensional tolerances of the selective laser melting (SLM) process are not good enough for many industrial applications and grinding as a common finishing process introduces many surface modifications. Investigation on the effect of grinding induced surface residual stress (RS) on early stages of stress corrosion cracking (SCC) of SLM manufactured 316L austenitic stainless steel was conducted. Potentiodynamic and galvanostatic tests in a 3.5% NaCl aqueous solution, XRD, SEM and energy-dispersive X-ray spectroscopy (EDX) analysis were performed. For annealed and specimens with a low RS magnitude, the dominant observation was pit initiation from existing pores and growth in the build direction. For specimens with medium RS level, SCC initiation from pore sites and propagation along melt pool boundaries and for specimens with the highest detected RS, crack initiation from melt pool boundaries, grains, machining marks, and pore sites were observed. Cracks propagated in different directions, i.e., along melt pool boundaries, near-surface transgranular, and transgranular through columnar microstructure. Galvanostatic tests showed three distinctive regions that corresponded to crack and pit initiation and growth. The synergistic effect of high dislocation density along melt pool boundaries, stress concentration in pore sites, molybdenum segregation, and surface RS was the cause of SCC susceptibility of specimens with high RS magnitude.


CORROSION ◽  
1969 ◽  
Vol 25 (1) ◽  
pp. 23-29 ◽  
Author(s):  
B. HILL ◽  
L. F. TRUEB

Abstract Intergranular corrosion of stabilized austenitic stainless steel is not accelerated when this material is explosion-clad to carbon steel. Heat-treatment in the sensitization range causes carbon diffusion across the bond interface and precipitation of chromium carbides; this influences the corrosion rates within the diffusion band. Outside of this relatively small area, corrosion rates are similar to those characteristic of nonclad material subjected to the same heat treatment. Stress corrosion cracking of both a stabilized and an unstabilized grade of austenitic stainless steel is not accelerated by explosion cladding to carbon steel. Stainless steel-to-steel explosion clads thus do not appear to pose any special corrosion problems.


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