scholarly journals Forming Process, Microstructure, and Mechanical Properties of Thin-Walled 316L Stainless Steel Using Speed-Cold-Welding Additive Manufacturing

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 109 ◽  
Author(s):  
Wei Wu ◽  
Jiaxiang Xue ◽  
Leilei Wang ◽  
Zhanhui Zhang ◽  
Yu Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Scanning Speed ◽  
Cooling Time ◽  
Bottom Current ◽  
Cold Welding ◽  
Thin Walled

Wire and arc additive manufacturing (WAAM) produces thin-walled parts superior to other additive manufacturing methods, because of its high efficiency, good compactability, and low cost. However, the WAAM accuracy is limited by its large heat input. Here, 0.8 mm 316L stainless steel welding wire is deposited via speed cold welding to form 30-layered thin-walled samples, with 2 mm thickness, and up to 65 mm height. The effects of three process parameters (the bottom current mode, scanning speed, and cooling time) on the deposition process stability, macro morphology, structure, and mechanical properties are studied. In the experiment, the probability density curves of electrical parameters of sample #GRBC-30 cm/min-10 s on the third and tenth layers were narrower than other samples, which implied a more stable process. The three process parameters mainly affect the deposition morphology and have a minor performance effect. The hardness and tensile properties mainly depend on the deposition direction. Gradual, layer-by-layer current reduction improves the bottom molding and performance, and the deposition efficiency, and stabilizes the process. Scanning speed enhancement or cooling time reduction destabilizes the end formation, reduces the effective deposition rate, and slightly degrades the performance. All deposited samples are distinctly anisotropic, but satisfy the industrial standard. Overall, deposition in speed cold welding mode, with 10 s cooling time, 30 cm/min scanning speed, and gradually reduced bottom current exhibits good stability, and the molding efficiency and mechanical properties are optimal.

scholarly journals Effect of Powder Feedstock on Microstructure and Mechanical Properties of the 316L Stainless Steel Fabricated by Selective Laser Melting

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 729 ◽  
Author(s):  
Wei Chen ◽  
Guangfu Yin ◽  
Zai Feng ◽  
Xiaoming Liao
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Hierarchical Structures ◽  
Fine Powder ◽  
Tensile Tests ◽  
Laser Melting ◽  
Powder Feedstock

Additive manufacturing by selective laser melting (SLM) was used to investigate the effect of powder feedstock on 316L stainless steel properties include microstructure, relative density, microhardness and mechanical properties. Gas atomized SS316L powders of three different particle size distribution were used in this study. Microstructural investigations were done by scanning electron microscopy (SEM). Tensile tests were performed at room temperatures. Microstructure characterization revealed the presence of hierarchical structures consisting of solidified melt pools, columnar grains and multiform shaped sub-grains. The results showed that the SLM sample from the fine powder obtained the highest mechanical properties with ultimate tensile strength (UTS) of 611.9 ± 9.4 MPa and yield strength (YS) of 519.1 ± 5.9 MPa, and an attendant elongation (EL) of 14.6 ± 1.9%, and a maximum of 97.92 ± 0.13% and a high microhardness 291 ± 6 HV0.1. It has been verified that the fine powder (~16 μm) could be used in additive manufacturing with proper printing parameters.

Microstructure and Mechanical Properties of Electron Beam Deposits of AISI 316L Stainless Steel

2011 ◽  
Author(s):  
Liang Wang ◽  
Sergio D. Felicelli ◽  
Jacob Coleman ◽  
Rene Johnson ◽  
Karen M. B. Taminger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Electron Beam ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Beam Current ◽  
Aisi 316L ◽  
Translation Speed ◽  
Aisi 316L Stainless Steel ◽  
Microstructure And Mechanical Properties

Electron beam freeform fabrication (EBF3) is a process that uses an electron beam and wire feedstock to fabricate metallic parts inside a vacuum chamber. In this study, single and multiple layer linear deposits of AISI 316L stainless steel were produced with the EBF3 machine at NASA Langley Research Center (LaRC). EBF3 process parameters, including beam current, translation speed, and wire feed rate, were investigated in order to consider their effects on the resulting steel deposit geometry, microstructure and mechanical properties. Results indicate that the EBF3 process can produce pore-free, fully dense material within the range of process parameters used in this study. The electron beam deposited stainless steel has a solidification microstructure with fine columnar grains within most parts of the deposit due to the high cooling rate during the deposition, with some small homogeneous equiaxed grains at the top of the deposit. The mechanical properties of the deposits are comparable to those of wrought metal, which is attributed to the homogeneous fine-grained microstructure.

scholarly journals Fabrication of superhydrophilic surfaces for long time preservation on 316L stainless steel by ultraviolet laser etching

2022 ◽  
Author(s):  
Chunyang Pan ◽  
Changfeng Xu ◽  
Jun Zhou
Keyword(s):  
Stainless Steel ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Scanning Speed ◽  
Textured Surface ◽  
Laser Process ◽  
Maintenance Time ◽  
316L Steel ◽  
Long Time ◽  
Good Biocompatibility

Abstract Due to the good biocompatibility, 316L stainless steel is widely used in the manufacture of medical instru-ments and human implants. The super hydrophilic 316L steel surface is used for reducing friction and adhe-sion. By choosing appropriate laser process parameters 316L steel surfaces with super-hydrophilic were ob-tained. The effects of laser process parameters including repeat frequency, pulse width, scanning speed, and the number of scanning were investigated to find the relationship between surface microstructure and wet-ting ability. To investigate the super-hydrophilic maintenance time on the textured surface, the textured sur-faces were preserved in ambident air, distilled water, and absolute ethanol. The results showed that by choosing appropriate laser process parameters surface with super-hydrophilicity can be maintained for 30 days.

scholarly journals Additive Manufacturing of 316L Stainless Steel

2019 ◽  
Vol 8 (4) ◽  
pp. 6825-6829 ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Computer Aided Design ◽  
316L Stainless Steel ◽  
Electrical Discharge Machining ◽  
Sheet Material ◽  
Physical And Mechanical Properties ◽  
Layer By Layer ◽  
Graded Material

Additive manufacturing (AM) is a process of making parts by adding ultrathin layers of materials such as liquid, powder or sheet material layer by layer using 3D printing machine with the aid of a computer-aided design (CAD) software from 3D model data. Intricate, complex parts with graded material can be fabricated with ease. However, additively manufactured parts can vary in physical and mechanical properties with conventionally manufactured parts. In this final year project, AM was done using metal powder of 316L stainless steel alloy owing to good corrosion resistance, ductility and strength. The main objectives for this project are to fabricate 316L stainless steel using AM and to study the physical and mechanical properties of the addictively manufactured specimens compared with electrical discharge machining (EDM) wire cut specimens. A standard specimen bone shaped were manufactured in accordance with ASTM E8 and followed by physical and mechanical testing. From the testing and analysis, 316L stainless steel samples manufactured via AM route have the ultimate tensile strength ranged from 514 to 520 MPa while EDM specimens ranged from 574 to 576 MPa, the yield strength of AM specimens ranged from 385 to 390 MPa while EDM specimens ranged from 350 to 355 MPa, and the average elongation at failure of AM specimens are 45% while EDM specimens are 66%. From this project, it shows that AM specimens have comparable physical and mechanical properties with EDM specimens.

scholarly journals Influence of Powder Deposition on Powder Bed and Specimen Properties

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 297 ◽  
Author(s):  
Steffen Beitz ◽  
Roland Uerlich ◽  
Tjorben Bokelmann ◽  
Alexander Diener ◽  
Thomas Vietor ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Confocal Laser ◽  
Micro Computed Tomography ◽  
Powder Bed ◽  
Powder Deposition

Three-dimensional printing used to be a rapid prototyping process, but nowadays it is establishing as an additive manufacturing (AM) process. One of these AM techniques is selective laser sintering (SLS), which most often involves partial melting of the particles and therefore belongs to the category of powder bed fusion processes. Much progress has been made in this field by research on process parameters like laser power, hatch distance, and scanning speed while still lacking a fundamental understanding of the powder deposition and its influence on parts. A critical issue for economic manufacturing is the building time of parts with good mechanical properties, which can be reduced by lower surface roughness due to less or missing post processing. Therefore, the influence of three blade shapes on powder bed surface roughness has been evaluated for PA12 powder with three different grain size distributions by using advanced X-ray micro computed tomography (XMT) and a confocal laser scanning microscope (LSM). Along with those methods, new techniques for powder characterization were tested and compared. Lowest roughness has been achieved with a flat blade, based on a higher compression due to a larger contact zone between blade and powder bed. Furthermore, an anisotropic effect of the mechanical properties resulting from different building directions has been detected which can be explained by varying amounts of solid contact paths through the powder bed depending on powder application direction. In addition, an optimal combination of process parameters with an even compression of the powder bed leads to low surface roughness, complementing the advantages of additive manufacturing.

Wire Arc Additive Manufacturing of Stainless Steels: A Review

2020 ◽  
Vol 10 (5) ◽  
pp. 1563 ◽  
Author(s):  
Wanwan Jin ◽  
Chaoqun Zhang ◽  
Shuoya Jin ◽  
Yingtao Tian ◽  
Daniel Wellmann ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Stainless Steels ◽  
Heat Treatments ◽  
Physical Metallurgy ◽  
Deposition Rates ◽  
Wire Arc Additive Manufacturing

Wire arc additive manufacturing (WAAM) has been considered as a promising technology for the production of large metallic structures with high deposition rates and low cost. Stainless steels are widely applied due to good mechanical properties and excellent corrosion resistance. This paper reviews the current status of stainless steel WAAM, covering the microstructure, mechanical properties, and defects related to different stainless steels and process parameters. Residual stress and distortion of the WAAM manufactured components are discussed. Specific WAAM techniques, material compositions, process parameters, shielding gas composition, post heat treatments, microstructure, and defects can significantly influence the mechanical properties of WAAM stainless steels. To achieve high quality WAAM stainless steel parts, there is still a strong need to further study the underlying physical metallurgy mechanisms of the WAAM process and post heat treatments to optimize the WAAM and heat treatment parameters and thus control the microstructure. WAAM samples often show considerable anisotropy both in microstructure and mechanical properties. The new in-situ rolling + WAAM process is very effective in reducing the anisotropy, which also can reduce the residual stress and distortion. For future industrial applications, fatigue properties, and corrosion behaviors of WAAMed stainless steels need to be deeply studied in the future. Additionally, further efforts should be made to improve the WAAM process to achieve faster deposition rates and better-quality control.

Optimization and analysis of porosity and roughness in selective laser melting 316L parts

2018 ◽  
Vol 1 (90) ◽  
pp. 5-15 ◽  
Author(s):  
M. Król ◽  
J. Mazurkiewicz ◽  
S. Żołnierczyk
Keyword(s):  
Stainless Steel ◽  
Additive Manufacturing ◽  
Laser Beam ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
316L Stainless Steel ◽  
Selective Laser Sintering ◽  
Technological Parameters ◽  
Laser Melting ◽  
Research Issues

Purpose: The investigations have been carried out on 316L stainless steel parts fabricated by Selective Laser Melting (SLM) technique. The study aimed to determine the effect of SLM parameters on porosity, hardness, and structure of 316L stainless steel. Design/methodology/approach: The analyses were conducted on 316L stainless steel parts by using AM125 SLM machine by Renishaw. The effects of the different manufacturing process parameters as power output, laser distance between the point’s melted metal powder during additive manufacturing as well as the orientation of the model relative to the laser beam and substrate on porosity, hardness, microstructure and roughness were analysed and optimised. Findings: The surface quality parts using 316L steel with the assumed parameters of the experiment depends on the process parameters used during the SLM technique as well as the orientation of formed walls of the model relative to the substrate and thus the laser beam. The lowest roughness of 316L SLM parts oriented perpendicularly to the substrate was found when 100 W and 20 μm the distance point was utilised. The lowest roughness for part oriented at 60° relatives to the substrate was observed when 125 W and the point distance 50 μm was employed. Practical implications: Stainless steel is one of the most popular materials used for selective laser sintering (SLM) processing to produce nearly fully dense components from 3D CAD models. Reduction of porosity is one of the critical research issues within the additive manufacturing technique SLM, since one of the major cost factors is the post-processing. Originality/value: This manuscript can serve as an aid in understanding the importance of technological parameters on quality and porosity of manufactured AM parts made by SLM technique.

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