scholarly journals Studying the Microstructural Effect of Selective Laser Melting and Electropolishing on the Performance of Maraging Steel

2021 ◽  
Author(s):  
D. Ahmadkhaniha ◽  
H. Möller ◽  
C. Zanella
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cross Section ◽  
Corrosion Behavior ◽  
Main Role ◽  
Laser Melting ◽  
Heat Treated ◽  
Manufacturing Technologies

AbstractSelective laser melting is one of the additive manufacturing technologies that have been known for building various and complicated shapes. Despite numerous advantages of additive manufacturing technologies, they strongly influence the microstructure and typically show a relatively high surface roughness. In this study, maraging steel was produced by selective laser melting (SLM), and its microstructure, hardness and corrosion behavior before and after heat treatment were studied and compared to traditionally manufactured ones (wrought, forged samples). In addition, the effect of electropolishing on the surface roughness was evaluated. The microstructural study was carried out by scanning electron microscopy equipped with electron backscattered diffraction in three different sections: parallel to the top surface (xy), transverse cross section (xz) and longitudinal cross section (yz). The same characterization was applied to heat-treated samples, austenitized and quenched as well as the aged ones. The results showed that selective laser melting produced a fine grain martensitic structure (in the as-printed condition) with a surface roughness (Ra) of about 10 µm. There was no sign of preferred texture or anisotropy in the microstructure of as-print SLM materials. The SLM microstructure was similar in all 3 sections (xy, xz and yz). Despite finer microstructure, nano-hardness and corrosion behavior of SLM and conventional wrought maraging steel in heat-treated conditions were similar. Aging resulted in the maximum nano-hardness and the minimum corrosion potential values. Precipitation has the main role in both hardness and corrosion behavior. Electropolishing was optimized and reduced the surface roughness (Ra) by 65%.

scholarly journals Improving surface quality in selective laser melting based tool making

2021 ◽  
Author(s):  
Filippo Simoni ◽  
Andrea Huxol ◽  
Franz-Josef Villmer
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Remelting ◽  
Laser Melting ◽  
Great Cost ◽  
Starting Point ◽  
Processing Techniques

AbstractIn the last years, Additive Manufacturing, thanks to its capability of continuous improvements in performance and cost-efficiency, was able to partly replace and redefine well-established manufacturing processes. This research is based on the idea to achieve great cost and operational benefits especially in the field of tool making for injection molding by combining traditional and additive manufacturing in one process chain. Special attention is given to the surface quality in terms of surface roughness and its optimization directly in the Selective Laser Melting process. This article presents the possibility for a remelting process of the SLM parts as a way to optimize the surfaces of the produced parts. The influence of laser remelting on the surface roughness of the parts is analyzed while varying machine parameters like laser power and scan settings. Laser remelting with optimized parameter settings considerably improves the surface quality of SLM parts and is a great starting point for further post-processing techniques, which require a low initial value of surface roughness.

scholarly journals Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM)

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3603
Author(s):  
Tim Pasang ◽  
Benny Tavlovich ◽  
Omry Yannay ◽  
Ben Jakson ◽  
Mike Fry ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Tensile Strength ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Electron Beam Melting ◽  
Rolling Direction ◽  
Laser Melting ◽  
Plate Rolling

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°—relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α′ martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.

ANISOTROPIC CUTTING FORCE CHARACTERISTICS IN MILLING OF MARAGING STEEL PROCESSED THROUGH SELECTIVE LASER MELTING

2021 ◽  
pp. 1-16
Author(s):  
Shoichi Tamura ◽  
Takashi Matsumura ◽  
Atsushi Ezura ◽  
Kazuo Mori
Keyword(s):  
Additive Manufacturing ◽  
Cutting Force ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cutting Forces ◽  
Manufacturing Process ◽  
Laser Scanning ◽  
Force Model ◽  
Laser Melting ◽  
Scanning Direction

Abstract Additive manufacturing process of maraging steel has been studied for high value parts in aerospace and automotive industries. The hybrid additive / subtractive manufacturing is effective to achieve tight tolerances and surface finishes. The additive process induces anisotropic mechanical properties of maraging steel, which depends on the laser scanning direction. Because anisotropy in the workpiece material has an influence on the cutting process, the surface finish and the dimension accuracy change according to the direction of the cutter feed with respect to the laser scanning direction. Therefore, the cutting parameters should be determined to control the cutting force considering material anisotropy. The paper discusses the cutting force in milling of maraging steel stacked with selective laser melting, as an additive manufacturing process. Anisotropic effect on the cutting forces is proved with the changing rate of the cutting force in milling of the workpieces stacked by repeating laser scanning at 0/90 degrees and 45/-45 degrees. The cutting forces, then, are analyzed in the chip flow models with piling up of orthogonal cuttings. The force model associates anisotropy with the shear stress on the shear plane. The changes in the cutting forces with the feed direction are discussed in the cutting tests and analysis.

Anisotropic Cutting Force Characteristics in Milling of Maraging Steel Processed Through Selective Laser Melting

2021 ◽  
Author(s):  
Shoichi Tamura ◽  
Takashi Matsumura ◽  
Atsushi Ezura ◽  
Kazuo Mori
Keyword(s):  
Additive Manufacturing ◽  
Cutting Force ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cutting Forces ◽  
Manufacturing Process ◽  
Laser Scanning ◽  
Force Model ◽  
Laser Melting ◽  
Scanning Direction

Abstract Additive manufacturing process of maraging steel has been studied for high value parts in aerospace and automotive industries. The hybrid additive / subtractive manufacturing is effective to achieve tight tolerances and surface finishes. The additive process induces anisotropic mechanical properties of maraging steel, which depends on the laser scanning direction. Because anisotropy in the workpiece material has an influence on the cutting process, the surface finish and the dimension accuracy change according to the direction of the cutter feed with respect to the laser scanning direction. Therefore, the cutting parameters should be determined to control the cutting force considering material anisotropy. The paper discusses the cutting force in milling of maraging steel stacked with selective laser melting, as an additive manufacturing process. Anisotropic effect on the cutting forces is proved with the changing rate of the cutting force in milling of the workpieces stacked by repeating laser scanning at 0/90 degrees and 45/−45 degrees. The cutting forces, then, are analyzed in the chip flow models with piling up of orthogonal cuttings. The force model associates anisotropy with the shear stress on the shear plane. The changes in the cutting forces with the feed direction are discussed in the cutting tests and analysis.

scholarly journals Effect of Process Parameters on the Generated Surface Roughness of Down-Facing Surfaces in Selective Laser Melting

2019 ◽  
Vol 9 (6) ◽  
pp. 1256 ◽  
Author(s):  
Amal Charles ◽  
Ahmed Elkaseer ◽  
Lore Thijs ◽  
Veit Hagenmeyer ◽  
Steffen Scholz
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Process Models ◽  
Average Error ◽  
Lead Times ◽  
Laser Melting ◽  
Optimization Of Process Parameters ◽  
The Difference

Additive manufacturing provides a number of benefits in terms of infinite freedom to design complex parts and reduced lead-times while globally reducing the size of supply chains as it brings all production processes under one roof. However, additive manufacturing (AM) lags far behind conventional manufacturing in terms of surface quality. This proves a hindrance for many companies considering investment in AM. The aim of this work is to investigate the effect of varying process parameters on the resultant roughness of the down-facing surfaces in selective laser melting (SLM). A systematic experimental study was carried out and the effects of the interaction of the different parameters and their effect on the surface roughness (Sa) were analyzed. It was found that the interaction and interdependency between parameters were of greatest significance to the obtainable surface roughness, though their effects vary greatly depending on the applied levels. This behavior was mainly attributed to the difference in energy absorbed by the powder. Predictive process models for optimization of process parameters for minimizing the obtained Sa in 45° and 35° down-facing surface, individually, were achieved with average error percentages of 5% and 6.3%, respectively, however further investigation is still warranted.

The effect of support structures on maraging steel MS1 parts fabricated by selective laser melting at different building angles

2020 ◽  
Vol 26 (9) ◽  
pp. 1465-1476
Author(s):  
Qiqiang Cao ◽  
Jiong Zhang ◽  
Shuai Chang ◽  
Jerry Ying Hsi Fuh ◽  
Hao Wang
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Vickers Microhardness ◽  
Support Structures ◽  
Laser Melting ◽  
Supporting Surface ◽  
Content Type ◽  
Printing Quality

Purpose This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and 75° building angles. Design/methodology/approach Two groups of samples, one group with support structures and the other group without support structures, were designed with the same specifications and printed under the same conditions by SLM at 45°, 60° and 75° building angles. Differences in dimensional accuracy, surface roughness, Vickers microhardness, residual stress and microstructure were compared between groups. Findings The results showed that with support structures, more accurate dimension and slightly higher Vickers microhardness could be obtained. Larger compressive stress dominated and was more uniformly distributed on the supporting surface. Without support structures, the dimension became more precise as the building angle increased and alternating compressive and tensile stress was unevenly distributed on the supporting surface. In addition, the surface roughness of the outer surface decreased with the increase of the built angle, regardless of the support structures. Furthermore, whether the building angle was 45°, 60° or 75°, the observed microstructures revealed that the support structures altered the orientation of the molten pool and the direction of grain growth. Originality/value This paper studies the influence of support structures on the workpieces printed at different building angles. Support structures affect the residual stress distribution, heat dissipation rate and microstructure of the parts, and thus affecting the printing quality. Therefore, it is necessary to balance the support strategy and printing quality to better apply or design the support structures in SLM.

scholarly journals Additive manufacturing of WC reinforced maraging steel 300 composites by cold spraying and selective laser melting

2019 ◽  
Vol 371 ◽  
pp. 161-171 ◽  
Author(s):  
Xingchen Yan ◽  
Chunjie Huang ◽  
Chaoyue Chen ◽  
Rodolphe Bolot ◽  
Lucas Dembinski ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
Cold Spraying ◽  
Laser Melting

scholarly journals Experimental investigation of effect of printing direction and surface roughness on the mechanical properties of AlSi10Mg-alloy produced by selective laser melting

2021 ◽  
Author(s):  
Dmitry Vysochinskiy ◽  
Naureen Akhtar ◽  
Tord Nordmo ◽  
Mathias Rabjerg Strand ◽  
Adrian Vyssios ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Surface Roughness ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Material Strength ◽  
Laser Melting ◽  
Tension Tests ◽  
Printing Direction ◽  
Effect Of Surface

The additive manufacturing has initially gained popularity for production of non-loadbearing parts and components or in the fields where the material strength and ductility are less important such as modelling and rapid prototyping. But as the technology develops, availability of metal additive manufacturing naturally dictates the desire to use the produced components in load-bearing parts. This requires not-only a thorough documentation on the mechanical properties but also additional and independent research to learn the expected level of variation of the mechanical properties and what factors affect them. The presented paper investigates strength, ductility, hardness, and microstructure of the AlSi10Mg alloy produced by the selective laser melting (SLM). The mechanical properties were determined through a series of uniaxial tension tests and supplementary hardness tests and rationalized with the microstructure evolution with regard to printing direction and heat treatment. The paper also addresses the effect of surface roughness on the mechanical properties of the material, by comparing the machined and net shape tension samples. As expected, the as-manufactured AlSi10Mg-alloy appears to be a semi-brittle alloy, but its microstructure can be altered, and ductility increased by a proper heat-treatment. The effect of surface layer removal on the measured mechanical properties is of particular interest.

Properties of Test Coupons Fabricated by Selective Laser Melting

2010 ◽  
Vol 447-448 ◽  
pp. 780-784 ◽  
Author(s):  
A. Liu ◽  
Chee Kai Chua ◽  
Kah Fai Leong
Keyword(s):  
Surface Roughness ◽  
Selective Laser Melting ◽  
Fibre Laser ◽  
Fibre Lasers ◽  
Laser Melting ◽  
Superior Result ◽  
Heat Treated ◽  
Diode Pumped ◽  
Part Density ◽  
Better Than

Selective Laser Melting (SLM) is a popular and promising Additive Manufacturing (AM) technique as it can produce parts with complex internal features with part density close to 100%. However, unprocessed raw SLM fabricated parts have surface roughness issues and the mechanical properties of raw SLM parts without heat treatment are not ideal. The material used to address some of these issues in this research is an Aluminum alloy, AlSi10Mg – a strong and light weight metal. The SLM machine engaged for the test coupons fabrication is M2 Cusing from Concept Laser, Germany, which uses a diode pumped Yb-Fibre laser (Ytterbium-doped fibre lasers) with an effective output power of 200W. It is found that SLM fabricated parts with and without sandblasting shows up to 80% difference in surface roughness values. Also, the tensile test experiments of raw untreated SLM parts carried out at room temperature and at high temperature (200oC) show superior result compared with heat treated casted parts. Other properties such as hardness and density (porosity) are found to be better than heat treated cast parts as well.

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