scholarly journals Influence of Preheating Temperature on Hardness and Microstructure of PBF Steel hs6-5-3-8

2021 ◽  
Author(s):  
Jasmin Saewe ◽  
Markus Benjamin Wilms ◽  
Lucas Jauer ◽  
Johannes Schleifenbaum
Keyword(s):  
Carbon Content ◽  
High Speed ◽  
Electron Backscatter Diffraction ◽  
State Of The Art ◽  
Base Plate ◽  
Engineering Industry ◽  
Nickel Aluminum ◽  
Powder Bed ◽  
Preheating Temperature ◽  
Backscatter Diffraction

Laser powder bed fusion (LPBF) is an additive manufacturing process employed in many industries, for example for aerospace, automotive and medical applications. In these sectors, mainly nickel-, aluminum- and titanium-based alloys are used. In contrast, the mechanical engineering industry is interested in more wear-resistant steel alloys with higher hardness, both of which can be achieved with a higher carbon content, like in high-speed steels. Since these steels are susceptible to cracking, preheating needs to be applied during processing by LPBF. In a previous study, we applied a base plate preheating temperature of 500 °C for HS6-5-3-8 with 1.3 % carbon content. We were able to manufacture dense (p > 99.9 %) and crack-free parts from HS6-5-3-8 with a hardness > 62 HRC (as built) by LPBF. In this study, we investigate the influence of preheating temperatures up to 600 °C on hardness and microstructure dependent on part height for HS6-5-3-8. The microstructure was studied by light optical microscopy (LOM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The analysis of hardness and microstructure at different part heights is necessary because state-of-the-art preheating systems induce heat only into the base plate. Consequently, parts are subjected to temperature gradients and different heat treatment effects depending on part height during the LPBF process.

scholarly journals Microstructure and Properties of SLM High Speed Steel

2021 ◽  
Author(s):  
Olsson Elin ◽  
Sundin Stefan ◽  
Ma Taoran ◽  
Proper Sebastian ◽  
Lyphout Christophe ◽  
...  
Keyword(s):  
Carbon Content ◽  
High Speed ◽  
High Speed Steel ◽  
High Hardness ◽  
Base Plate ◽  
Thermal Gradients ◽  
High Carbon Content ◽  
Powder Bed ◽  
New Applications ◽  
Good Heat

Selective laser melting (SLM) is a commonly used laser powder bed technique where the final properties are influenced by many different powder related properties, such as particle size distribution, chemical composition and flowability. In applications where high hardness, wear resistance, strength and good heat properties are required, high speed steels (HSS) are widely used today. HSS has high carbon content and are therefore considered as unweldable. The rapidly growing implementation of AM technologies has led to a growing range of new applications and demands for new alloys and properties. The interest in being able to manufacture HSS by SLM without cracking is therefore increasing. In SLM, it is possible to preheat the base plate to a few hundred degrees Celsius which has been used for HSS and proved successful due to reduced thermal gradients. In this study, the properties of SLM produced high speed steel PEARL Micro®2012 with a carbon content of 0.61 wt.-% have been investigated and compared to those of a forged and rolled PM-HIP counterpart ASP®2012.

Specifics of Microstructure and Phase Composition of High-Speed Steel R6M5

2013 ◽  
Vol 404 ◽  
pp. 20-24 ◽  
Author(s):  
Маzhyn Skakov ◽  
Bauyrzhan Rakhadilov ◽  
Gaukhar Karipbayeva
Keyword(s):  
Phase Composition ◽  
High Speed ◽  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
High Speed Steel ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Steel R6m5 ◽  
Solid Carbide ◽  
Backscatter Diffraction

In this paper microstructure, morphology, elemental composition, phase composition and crystal structure of the sample steel R6M5 were investigate by using the methods of scanning electron microscopy, electron backscatter diffraction (EBSD) analysis and X-ray diffraction (XRD) analysis. Determined that the microstructure of steel R6M5 after hardening and three-time tempering consists of tempered martensite and solid carbide M6C and MC-type with spherical shape and a diameter of less than 3 μm. Detected that the volume fraction of each carbide amounted to 10.4±0.6% and 2.3±0.4% - for grey and bright carbides, respectively, and that the sizes of bright carbides particles in the microstructure of steel R6M5 are 0.4-4,5 μm, and the sizes of grey carbides particles are 0.5-1.1 μm. XRD analysis showed that the main carbides in the studied steel are carbides М6С and MC, which have complicated the FCC crystal lattice and the Fd3m spatial group. Determined that carbides are uniform and monocrystalline. ESBD analysis with the support of the XRD analysis showed that carbides spherical shape М6С fit to Fe3W3C composition.

Effect of Cryogenic Temperature Rolling on High Speed Impact Behavior of AA 6082 Thin Targets

2019 ◽  
Author(s):  
Rahul Dubey ◽  
Raja Allavikutty ◽  
R. Velmurugan ◽  
R. Jayaganthan
Keyword(s):  
High Speed ◽  
Electron Backscatter Diffraction ◽  
Impact Behavior ◽  
Final Thickness ◽  
High Speed Impact ◽  
Gas Gun ◽  
Potential Applications ◽  
Ballistic Properties ◽  
Impact Data ◽  
Backscatter Diffraction

Abstract Aluminium alloy AA 6082-T6 was rolled at cryogenic and room temperatures to final thickness of 0.5 mm after 75% thickness reduction and subjected to high speed impact. The deformed alloy was investigated for its ballistic properties due to potential applications in aerospace and automotive sectors. The cryogenic and room temperature rolled samples were subjected to normal high-speed impact using a gas gun arrangement to shoot nosed projectiles at velocities higher than the ballistic limits. Phantom ‘V611’ high-speed camera was used to measure the initial and residual velocities of the projectile. Nano-indentation was performed to relate hardness of the initial sample with the observed impact behaviour. Detailed fractographic studies were conducted using Scanning Electron Microscopy (SEM) to substantiate the possible failure mechanisms upon impact. Electron Backscatter Diffraction (EBSD) and Energy Dispersive X-ray Spectroscopy (EDS) were used to characterize the microstructure of the deformed samples. The high speed impact data is correlated with the metallographic observations in this study.

scholarly journals Structure / Property (Constitutive and Dynamic Strength / Damage) Behavior of Additively Manufactured Tantalum

2018 ◽  
Vol 183 ◽  
pp. 03002
Author(s):  
George.T. Gray ◽  
Veronica Livescu ◽  
Cameron Knapp ◽  
David R. Jones ◽  
Saryu Fensin ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Damage Evolution ◽  
Electron Backscatter Diffraction ◽  
Dynamic Strength ◽  
Functional Requirements ◽  
Structure Property ◽  
Powder Bed ◽  
Static Mechanical ◽  
Backscatter Diffraction ◽  
Dynamic Damage

For Certification and qualification of an engineering component generally involves meeting engineering and physics requirements tied to its functional requirements. In this paper, the results of a study quantifying the microstructure, mechanical behavior, and the dynamic damage evolution of Tantalum (Ta) fabricated using an EOS laser-powder-bed machine are presented. The microstructure and quasi-static mechanical behavior of the AM-Ta is detailed and compared / contrasted to wrought Ta. The dynamic damage evolution and failure response of the AM-Ta material, as well as wrought Ta, was probed using flyer-plate impact driven spallation experiments. The differences in the spallation response between the AM and wrought Ta were measured using in-situ velocimetry as well as post-mortem quantification of damage in “soft-recovered” samples. The damage evolution of the AM and wrought Ta were characterized using both optical metallography and electron-backscatter diffraction.

scholarly journals Recent Advances in High-Speed Orientation Mapping

2006 ◽  
Vol 14 (6) ◽  
pp. 6-9 ◽  
Author(s):  
Matthew M. Nowell ◽  
Martina Chui-Sabourin ◽  
John O. Carpenter
Keyword(s):  
High Speed ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Automated Analysis ◽  
Steady Increase ◽  
Analysis Tool ◽  
Early Adopters ◽  
Orientation Mapping ◽  
Backscatter Diffraction ◽  
Acquisition Rates

Orientation mapping via automated analysis of Electron Backscatter Diffraction (EBSD) patterns has developed into an established microstructural analysis tool in the electron microscopy community. From the early 1990s, when this technique became commercially available, there has been a steady increase in the data acquisition rates as shown in Figure 1. Currently, orientation mapping speeds of over 200 analyzed patterns per second have been achieved. With these types of acquisition rates now available, the strategy on how to best use EBSD and orientation mapping has also shifted. Early adopters of this technique had to allocate hours of Scanning Electron Microscope (SEM) beam time in order to collect statistically significant data. With current technology, what was collected in hours can now be obtained in minutes. The goal of this article is to introduce this high-speed orientation mapping and present results illustrating the benefits of this capability.

scholarly journals Forming Mechanism of High-Speed Cold Roll Beating of Spline Tooth

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Ting Niu ◽  
Yong-Tang Li ◽  
Zhi-Qi Liu ◽  
Hui-Ping Qi
Keyword(s):  
Process Parameters ◽  
High Speed ◽  
Room Temperature ◽  
Electron Backscatter Diffraction ◽  
Forming Mechanism ◽  
Grain Sizes ◽  
Cold Roll ◽  
Subgrain Rotation ◽  
Electron Backscatter ◽  
Backscatter Diffraction

The spline tooth of ASTM 1045 was fabricated by high-speed cold roll-beating (HSCRB) process at room temperature. Microhardness of the spline tooth was examined by a nanoindenter. The grains and misorientation angle distributions were measured by electron backscatter diffraction (EBSD). The results showed that the microhardness was improved up to 1280 μm deep from the surface of the spine tooth. The microhardness and the grain sizes gradually decreased in the direction away from the surface. On the surface, the fraction of ultrafine grains increased up to about 90%, and the average grain diameter (which was ∼0.56 µm) decreased by 71.4%. The model of grain evolution during HSCRB process is proposed in this work. New grains appear first on the boundaries of the elongated grains within numerous subgrains. The elongated grains are refined as a result of subgrain rotation. By analyzing the HSCRB technical principle, we concluded that the process parameters affect the refinement degree of studied steel by determining beating pass, beating pass interval time, and strain rate.

scholarly journals Increasing the Productivity of Laser Powder Bed Fusion for Stainless Steel 316L through Increased Layer Thickness

2020 ◽  
Author(s):  
Alexander Leicht ◽  
Marie Fischer ◽  
Uta Klement ◽  
Lars Nyborg ◽  
Eduard Hryha
Keyword(s):  
Stainless Steel ◽  
Layer Thickness ◽  
Electron Backscatter Diffraction ◽  
Powder Layer ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Stainless Steel 316L ◽  
Powder Bed ◽  
Backscatter Diffraction ◽  
Am Processes

AbstractAdditive manufacturing (AM) is able to generate parts of a quality comparable to those produced through conventional manufacturing, but most of the AM processes are associated with low build speeds, which reduce the overall productivity. This paper evaluates how increasing the powder layer thickness from 20 µm to 80 µm affects the build speed, microstructure and mechanical properties of stainless steel 316L parts that are produced using laser powder bed fusion. A detailed microstructure characterization was performed using scanning electron microscopy, electron backscatter diffraction, and x-ray powder diffraction in conjunction with tensile testing. The results suggest that parts can be fabricated four times faster with tensile strengths comparable to those obtained using standard process parameters. In either case, nominal relative density of > 99.9% is obtained but with the 80 µm layer thickness presenting some lack of fusion defects, which resulted in a reduced elongation to fracture. Still, acceptable yield strength and ultimate tensile strength values of 464 MPa and 605 MPa were obtained, and the average elongation to fracture was 44%, indicating that desirable properties can be achieved.

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