| 1. |
- Kaplan, Alexander F. H., et al.
(författare)
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Laser induced reduction of iron ore by silicon
- 2023
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Ingår i: Journal of Alloys and Metallurgical Systems. - : Elsevier. - 2949-9178. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Iron ore powder accompanied by Si-powder as a reducing agent, was melted using a high-power laser beam. During laser melting of the two different powder beds placed next to each other, silicon merged and diffused into the iron ore, forming a ternary melt phase Fe-O-Si of around 30–60–10 at%. High speed imaging of the laser melting process as well as subsequent SEM-analysis of the generated nuggets showed the formation of droplets that merge with the surrounding Si- or ore-powder and form distinct domains. Under certain circumstances, the solidifying nuggets, of the order of 0.5–5 mm in size, generated numerous small domains, up to 25 µm, of high purity iron, 90 + at%, surrounded by a matrix of the above mentioned slag. Many of these Fe-domains were created in the vicinity of regions of high Si-content.
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| 2. |
- Ring-Groth, Margareta, et al.
(författare)
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Fatigue properties of weldbonded stainless steel joints
- 2000
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Ingår i: Journal of Advanced Materials. - 1070-9789. ; 32:1, s. 21-27
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Tidskriftsartikel (refereegranskat)abstract
- Weldbonding of stainless steel with an epoxy adhesive has been investigated with respect to fatigue life. Factors affecting joint strength have been identified and summarized. The weld-bonded joints were mechanically pre-treated, and weld-bonded as flanged single-overlap and cross-tension specimens. The results were compared with spot welded specimens of identical configuration. The weld-bonded specimens have better fatigue properties than spot welded specimens.
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| 3. |
- Ring-Groth, Margareta, et al.
(författare)
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Weldbonding of stainless steel : An introduction
- 1998
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Ingår i: Journal of Advanced Materials. - 1070-9789. ; 30:1, s. 36-39
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Tidskriftsartikel (refereegranskat)abstract
- Weldbonding is a method which combines the best mechanical features of resistance spot welding and adhesive bonding. For adhesive users, the technique simplifies the curing stage since no fixtures are needed for the period when the adhesive develops handling strength, and for spot weld users, the technique gives a joint a better mechanical properties and a sealed joint line. The bonds created are similar to normal spot welds but the joint is constrained by the adhesive at the interface. The adhesive is not present in the area surrounding the spot weld, since the heat generated between the stainless steel sheets burns the adhesive in that area
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| 4. |
- Bergström, David, et al.
(författare)
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A ray-tracing analysis of the absorption of light by smooth and rough metal surfaces
- 2007
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:11, s. 113504-1
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Tidskriftsartikel (refereegranskat)abstract
- Ray tracing has been employed to investigate the absorption of light by smooth and random rough metal surfaces. For normally incident light the absorptance of the surface increases with surface roughness. However, for light incident at a tangent to the surface the absorptance-surface roughness relationship is more complex. For example, in certain cases the absorptance can rise, fall, and rise again as the surface roughness increases. In this paper this complex absorptance-roughness relationship is defined and explained. The wavelengths of the light chosen for this study correspond to the primary and secondary output wavelengths of Nd:YAG lasers.
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| 5. |
- Bergström, David, et al.
(författare)
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Absorptance of Non-Ferrous Alloys to Nd:YLF and Nd:YAG Laser Light at Room Temperature
- 2007
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Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 46:8, s. 1290-1301
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of absorptance is important for the analysis and modelling of laser-material interactions. Unfortunately, most of the absorptance data presently available considers only polished pure metals rather than the commercially available (unpolished, oxidised) alloys which are actually being processed in manufacturing. This paper presents the results of absorptance measurements carried out at room temperature on as-received engineering grade non-ferrous metals (Al, Cu and Zn alloys). The measurements were made using an integrating sphere with an Nd:YLF laser at two wavelengths (1053nm and 527nm � which means that the results are also valid for Nd:YAG radiation at 1064nm and 532nm). The absorptance results obtained differ considerably from existing data for polished, pure metals and should help improve the accuracy of laser-material interaction models. Some clear trends were identified. For all 22 cases studied the absorptance was higher than for ideal pure, polished metals. For all Al- and Cu-samples the absorptance was higher for the green than it was for the infrared wavelength, while for all Zn-coatings this trend was reversed. No clear correlation between absorptance and surface roughness was found at low roughness values (Sa 0.15 � 0.60) but one, rougher set of samples (Sa 2.34), indicated a roughness-absorptance correlation at higher roughness levels.
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| 6. |
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| 7. |
- Bergström, David, et al.
(författare)
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The absorptance of steels to Nd:YLF and Nd:YAG laser light at room temperature
- 2007
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 253:11, s. 5017-5028
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Tidskriftsartikel (refereegranskat)abstract
- The measurement of absorptance is important for the analysis and modelling of laser-material interactions. Unfortunately, most of the absorptance data presently available considers only polished pure metals rather than the commercially available (unpolished, oxidised) alloys, which are actually being processed in manufacturing. This paper presents the results of absorptance measurements carried out at room temperature on as-received engineering grade steels including hot and cold rolled mild steel and stainless steels of various types. The measurements were made using an integrating sphere with an Nd:YLF laser at two wavelengths (1053 and 527 nm, which means that the results are also valid for Nd:YAG radiation at 1064 and 532 nm). The absorptance results obtained differ considerably from existing data for polished, pure metals and should help improve the accuracy of laser-material interaction models. Some clear trends were identified; for all materials studied, the absorptance was considerably higher than the previously published values for the relevant pure metals with polished surfaces. For all 15 samples the absorptance was higher for the green than for the infrared wavelength. No clear trend correlating the absorptance with the roughness was found for mild steel in the roughness range Sa 0.4-5.6 μm. A correlation between absorptance and roughness was noted for stainless steel for Sa values above 1.5 μm.
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| 8. |
- Bergström, David, et al.
(författare)
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The absorption of light by rough metal surfaces - a three-dimensional ray-tracing analysis
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:10, s. 103515-
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Tidskriftsartikel (refereegranskat)abstract
- The laser absorptance of rough surfaces has been investigated by using Monte Carlo simulations based on three-dimensional (3D) ray tracing. The influence of multiple scattering, shadowing, and the Fresnel-equation based angle dependence is discussed. The 3D results are compared to previously published results from a two-dimensional ray-tracing analysis and the different applications of the two models are explained.
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| 9. |
- Al-Mashikhi, S.O., et al.
(författare)
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An explanation of ‘striation free' cutting of mild steel by fibre laser
- 2009
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Ingår i: Lasers in manufacturing 2009. - Stuttgart : AT-Fachverlag.
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Konferensbidrag (refereegranskat)abstract
- This paper presents the results of an experimental and theoretical investigation into the phenomenon of ‘striation free cutting', which is a feature of fibre laser cutting of thin section mild steel. The paper concludes that the creation of very low roughness edges is related to an optimisation of the cut front geometry when the cut front is inclined at angles close to the Brewster angle for the laser - material combination. For purely geometric reasons this particular type of cut front optimisation is not possible for CO2 laser cutting of mild steel.
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| 10. |
- Al-Mashikhi, S.O, et al.
(författare)
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Heat affected zones and oxidation marks in fiber laser–oxygen cutting of mild steel
- 2011
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Ingår i: Journal of laser applications. - : Laser Institute of America. - 1042-346X .- 1938-1387. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- The effect of cutting speed and sheet thickness on surface oxidation and heat affected zones (HAZs) has been investigated for laser–oxygen cutting of mild steel sheet with a fiber laser. Optical and scanning electron micrographs were used to determine the extent of surface oxidation and HAZ from plan and cross-sectional views, respectively. The HAZ is consistently wider at the bottom of the cut compared to the HAZ at the top of the cut. With increasing speed, the width of the HAZ at the top of the cut decreases whereas the HAZ width at the bottom of the cut generally increases. No simple, direct relationship between HAZ width and surface oxidation was seen. However, it is possible to state that in each case considered here, the HAZ would be completely removed if they are machined back by a depth equal to the extent of the surface oxidation.
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