| 1. |
- Asnafi, Nader, 1960-, et al.
(författare)
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3D Metal Printing from an Industrial Perspective : Product Design, Production, and Business Models
- 2019
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - Vienna : Springer. - 0005-8912 .- 1613-7531. ; 164:3, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- This paper is focused on automotive stamping tools and dies as well as the impact of 3D metal printing and metals related 3D-printing on design and production of such tools and dies. The purpose has been to find out the current industrial potential of 3D-printing as far as lead time, costs, shapes, material usage, metal piece size, surface roughness, hardness, strength, and machinability are concerned. The business transformational impact of 3D-printing is also addressed in this paper. The obtained results show that the lead time can be halved, the costs are somewhat higher, and the strength, hardness, surface roughness, and machinability of the 3D-printed metallic tools and dies are as good as those of the conventionally made. The maximum size of a metal piece that can be 3D-printed today by Powder Bed Fusion (PBF) is, in the best case, 500 mm × 500 mm × 500 mm. 3D-printing can also be used for the pattern to make the mold box in iron and steel casting. It is also possible to eliminate the casting pattern, since the mold box can be 3D-printed directly. All this has started to have a large business impact, and it is therefore of great significance to outline and execute an action plan almost immediately.
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| 2. |
- Asnafi, Nader, 1960-, et al.
(författare)
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Editorial
- 2022
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 167:9, s. 407-407
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Asnafi, Nader, 1960-, et al.
(författare)
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Production Tools Made by Additive Manufacturing Through Laser-based Powder Bed Fusion
- 2020
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 165:(3), s. 125-136
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the design and production of stamping tools and dies for sheet metal components and injection molds for plastic components. Laser-based Powder Bed Fusion (LPBF) is the additive manufacturing method used in this investigation. Solid and topology optimized stamping tools and dies 3D-printed in DIN 1.2709 (maraging steel) by LPBF are approved/certified for stamping of up to 2‑mm thick hot-dip galvanized DP600 (dual-phase steel sheet). The punch in a working station in a progressive die used for stamping of 1‑mm thick hot-dip galvanized DP600 is 3D-printed in DIN 1.2709, both with a honeycomb inner structure and after topology optimization, with successful results. 3D printing results in a significant lead time reduction and improved tool material efficiency. The cost of 3D-printed stamping tools and dies is higher than the cost of those made conventionally. The core (inserts) of an injection mold is 3D-printed in DIN 1.2709, conformal cooling optimized and 3D-printed in Uddeholm AM Corrax, and compared with the same core made conventionally. The cooling and cycle time can be improved, if the injection molding core (inserts) is optimized and 3D-printed in Uddeholm AM Corrax. This paper accounts for the results obtained in the above-mentioned investigations.
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| 4. |
- Asnafi, Nader, 1960-
(författare)
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Tool and Die Making, Surface Treatment, and Repair by Laser-based Additive Processes
- 2021
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 166:5, s. 225-236
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Tidskriftsartikel (refereegranskat)abstract
- This paper explores the possibilities to use laser-based additive processes to make, surface treat and repair/remanufacture tools, dies and molds for cold working, hot working, and injection molding. The failures encountered in these applications are described. The materials used conventionally and in the laser additive processes are accounted for. The properties of the tools, dies and molds made by Laser-based Powder Bed Fusion (L-PBF) are as good as and in some cases better than the properties of those made in wrought materials. Shorter cycle time, reduced friction, smaller abrasive wear, and longer life cycle are some of the benefits of L‑PBF and Directed Energy Deposition with powder (DED-p) (or Laser Metal Deposition with powder, LMD‑p, or Laser Cladding, LC). L‑PBF leads to higher toolmaking costs and shorter toolmaking lead time. Based on a review of conducted investigations, this paper shows that it is possible to design and make tools, dies and molds for and by L‑PBF, surface functionalize them by DED-p (LMD‑p, LC), and repair/remanufacture them by DED-p (LMD‑p, LC). With efficient operational performance as the target for the whole tool life cycle, this combination of L‑PBF and DED-p (LMD‑p, LC) has the greatest potential for hot working and injection molding tools and the smallest for cold working tools (due to the current high L‑PBF and DED-p (LMD‑p, LC) costs).
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| 5. |
- Chai, Guocai, et al.
(författare)
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Creep Behavior in A Newly Developed Heat Resistant Austenitic Stainless Steel
- 2015
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 160:9, s. 400-405
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Tidskriftsartikel (refereegranskat)abstract
- UNS S31035 austenitic stainless steel grade is a newly developed advanced heat resistant material for use in coal fired boilers at metal temperatures up to 700 °C. This new grade that has recently got two AMSE code cases shows good resistance to steam oxidation and flue gas corrosion and high creep rupture strength. This paper will mainly focus on the characterization of long term structure stability and performances such as the creep behaviors at different temperatures for up to 86,000 h at high temperatures. The creep damage mechanisms were studied using electron transmission microscopy, electron backscatter diffraction, and electron channeling contrast image analysis. The results show that the creep strength is related to the intragranular nano particles that act as obstacles for dislocation movements. Plastic deformation and transgranular fracture is the main creep fracture mechanism in the creep test samples of UNS S31035. The material has good creep ductility by formation of twins during the creep test. This material has been installed and tested in several European power plants, and has shown good performance. The material is an excellent alternative for superheaters and reheaters in future high-efficient coal fired boilers with design material temperatures up to 700 °C, instead of more costly nickel based alloy.
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| 6. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
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3D Ore Characterization as a Paradigm Shift for Process Design and Simulation in Mineral Processing
- 2021
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 166:8, s. 384-389
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Tidskriftsartikel (refereegranskat)abstract
- Current advances and developments in automated mineralogy have made it a crucial key technology in the field of process mineralogy, allowing better understanding and connection between mineralogy and the beneficiation process. The latest developments in X‑ray micro-computed tomography (µCT) have shown a great potential to let it become the next-generation automated mineralogy technique. µCT’s main benefit lies in its capability to allow 3D monitoring of the internal structure of the ore sample at resolutions down to a few hundred nanometers, thus excluding the common stereological error in conventional 2D analysis. Driven by the technological and computational progress, µCT is constantly developing as an analysis tool and successively it will become an essential technique in the field of process mineralogy. This study aims to assess the potential application of µCT systems, for 3D ore characterization through relevant case studies. The opportunities and platforms that µCT 3D ore characterization provides for process design and simulation in mineral processing are presented.
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| 7. |
- Hulme-Smith, Christopher, 1989-, et al.
(författare)
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Spreadability Testing of Powder for Additive Manufacturing
- 2020
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer Nature. - 0005-8912 .- 1613-7531. ; 166:1, s. 9-13
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Tidskriftsartikel (refereegranskat)abstract
- The spreading of powders into thin layers is a critical step in powder bed additive manufacturing, but there is no accepted technique to test it. There is not even a metric that can be used to describe spreading behaviour. A robust, image-based measurement procedure has been developed and can be implemented at modest cost and with minimal training. The analysis is automated to derive quantitative information about the characteristics of the spread layer. The technique has been demonstrated for three powders to quantify their spreading behaviour as a function of layer thickness and spreading speed.
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| 8. |
- Hägg Mameng, Sukanya, et al.
(författare)
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Atmospheric Corrosion Resistance of Stainless Steel : Results of a Field Exposure Program in the Middle-East
- 2016
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer. - 0005-8912 .- 1613-7531. ; 161:1, s. 33-43
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Tidskriftsartikel (refereegranskat)abstract
- Stainless steels have been widely used as architectural and construction materials because of their high degree of corrosion resistance, unique aesthetic quality, and stability in an unpolluted atmosphere. Although stainless steel is highly corrosion resistant, localized corrosion can occur in certain environments, especially in marine atmospheric conditions if the appropriate grade is not used. Exposure of stainless steel to an environment more aggressive than the limiting conditions may be harmful to its aesthetic appearance and ultimately even to its load-bearing capacity. Selecting a suitable stainless steel grade requires knowledge of the actual location of the application and the atmospheric conditions. In terms of materials selection, the austenitic stainless steel grade 316/316L has proved a very popular choice for architectural applications in many locations, but it is not always suitable at demanding sites such as marine environments in the Middle-East. In such cases the use of a higher-performance grade, often in combination with a good surface finish and established cleaning routines, is required to maintain pristine surfaces.The main objective of this paper is to present information about the atmospheric corrosion resistance of a number of stainless steels in the Middle-East at a marine site. The results obtained are analysed and discussed in terms of factors affecting atmospheric corrosion of stainless steel such as the, alloying element level, surface roughness, surface treatment, and microclimate.
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| 9. |
- Lindwall, Greta, 1981-, et al.
(författare)
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Coarsening investigations of precipitates in PM tool steel grades - an effect of nitrogen
- 2012
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - : Springer Science and Business Media LLC. - 0005-8912 .- 1613-7531. ; 157:11, s. 406-413
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental and theoretical comparisons of the coarsening rate for the MX(X=C, N or C+N) precipitate in five different tool steel grades produced by PowderMetallurgy (PM). The alloys contain different amounts of nitrogen and carbon; ranging fromhigh carbon/low nitrogen to high nitrogen/low carbon. Common for the grades is a highamount of precipitate forming alloying elements resulting in a high fraction of hard phase.Experimentally we have found out that the nitrogen rich precipitates coarsen slower, both forhigher and lower carbon content, than the carbon rich precipitates. Coarsening simulations areperformed utilizing the DICTRA software and an agreement between calculations andmeasurements can be concluded.
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| 10. |
- Lundberg, Sven-Erik, et al.
(författare)
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Ultra high speed rolling of stainless steel wire rod by means of interstand tensions
- 2005
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - 0005-8912 .- 1613-7531. ; 150:1, s. 5-11
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Tidskriftsartikel (refereegranskat)abstract
- By introduction of an interstand tension in the order of 10% of the actual yield stress of the rolled material in the intermediate stage of wire rod rolling, it is possible to increase the intermediate reductions without excessive increase of energy supply for rolling. Thus, an eight passes finishing block can be replaced by two intermediate stands and a four stand finishing block of a module type. This configuration gives two improvements on the productivity in a wire rod mill for stainless steel. First, the finish rolling speed can be increased from typically 60 m/s up to 80 m/s, meaning 33% higher rolling rate. Second, the modern twin module block system gives the possibility to introduce a single family rolling system, which gives a reduction of the downtime for roll and groove changing in the order of 20% of the production time, depending on the product mix in the mill.
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