Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing

This study evaluates the effect of post-manufacturing treatment on the compressive performance of additively manufactured components. The components were thin cylindrical shells with an aspect ratio of 25:1 manufactured using laser powder bed fusion and that were then surface treated by means of sandblasting or turning. The as-printed and subsequently surface treated samples were uniaxially compressed until failure to depict the effect of the surface condition on the compressive mechanical behavior. The results show that as the surfaces became smoother via sandblasting, the average peak strength for buckling load improves negligibly (0.85%), whereas this effect reaches 6.5% upon surface layer removal via turning. Through microstructural investigation and co-relating this with an understanding of processing conditions existing in manufacturing itself, this effect is seen to be linked to contour scanning causing softening of the surface region in a component.

Section: Discussionmentioning

confidence: 99%

Effect of Surface Sandblasting and Turning on Compressive Strength of Thin 316L Stainless Steel Shells Produced by Laser Powder Bed Fusion

Mehta

Hryha

Nyborg

et al. 2021

“…Post-processing in combination with process control and optimization (and quality assurance) are addressed from different perspectives and for different materials and AM methods in [6][7][8].…”

Section: Contributionsmentioning

confidence: 99%

“…In very demanding corrosive atmospheres, the question is whether AM lowers or eliminates the risk of stress corrosion cracking (SCC) compared to welded 316L components. The authors of [8] concentrate on post-processing and its influence on the microstructure, and surface and subsurface residual stresses. The immersion tests with four-point-bending in an 80 • C magnesium chloride solution for SCC showed no difference between the AM and reference samples, even after a 674-h immersion [8].…”

Section: Contributionsmentioning

confidence: 99%

Metal Additive Manufacturing—State of the Art 2020

Asnafi

2021

“…Additive manufacturing (AM) technologies developed in the last two decades have been aimed mainly at producing complex geometrics with minimal machining finishes using powder bed fusion (PBF) technologies, mostly selective laser melting (SLM) and electron beam melting (EBM) [1][2][3][4][5][6][7][8][9][10][11][12]. However, these relatively expensive PBF technologies do not adequately address the need to produce large components with less complicated geometrics at affordable production costs [13,14].…”

Section: Introductionmentioning

confidence: 99%

The Effect of a Slow Strain Rate on the Stress Corrosion Resistance of Austenitic Stainless Steel Produced by the Wire Laser Additive Manufacturing Process

Bassis

Kotliar²,

Koltiar³

et al. 2021

The wire laser additive manufacturing (WLAM) process is considered a direct-energy deposition method that aims at addressing the need to produce large components having relatively simple geometrics at an affordable cost. This additive manufacturing (AM) process uses wires as raw materials instead of powders and is capable of reaching a deposition rate of up to 3 kg/h, compared with only 0.1 kg/h with common powder bed fusion (PBF) processes. Despite the attractiveness of the WLAM process, there has been only limited research on this technique. In particular, the stress corrosion properties of components produced by this technology have not been the subject of much study. The current study aims at evaluating the effect of a slow strain rate on the stress corrosion resistance of 316L stainless steel produced by the WLAM process in comparison with its counterpart: AISI 316L alloy. Microstructure examination was carried out using optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis, while the mechanical properties were evaluated using tensile strength and hardness measurements. The general corrosion resistance was examined by potentiodynamic polarization and impedance spectroscopy analysis, while the stress corrosion performance was assessed by slow strain rate testing (SSRT) in a 3.5% NaCl solution at ambient temperature. The attained results highlight the inferior mechanical properties, corrosion resistance and stress corrosion performance, especially at a slow strain rate, of the WLAM samples compared with the regular AISI 316L alloy. The differences between the WLAM alloy and AISI 316L alloy were mainly attributed to their dissimilarities in terms of phase compositions, structural morphology and inherent defects.