Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 323) Show all publications
Näsström, J., Brueckner, F. & Kaplan, A. (2020). A near-vertical approach to Laser Narrow Gap Multi-Layer Welding. Optics and Laser Technology, 121, Article ID 105798.
Open this publication in new window or tab >>A near-vertical approach to Laser Narrow Gap Multi-Layer Welding
2020 (English)In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 121, article id 105798Article in journal (Refereed) Published
Abstract [en]

A novel, near-vertical approach to the usually horizontal laser Narrow Gap Multi-Layer Welding process is introduced. The process is applied to join X100 pipeline steel and studied through High Speed Imaging. The produced welded joints are compared to their horizontally welded counterparts using 3D scanning, longitudinal & perpendicular cross sections and Computed Tomography analysis. The near-vertical approach is found to be robust and produce welded joints with a uniform appearance. The top surface exhibits certain reoccurring morphological features, and variations in internal track melting boundaries are observed. Any observed cavities appear similar to those produced using the horizontal process, with the difference of their orientation. A combination of the horizontal and the near-vertical process could be beneficial; the near-vertical approach offers potential for shorter inter-layer time and the horizontal method for better surface finish than that of its counterpart. Potential benefits of, and improvements to, the near-vertical process are discussed.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Laser welding, Narrow Gap, Vertical Welding, Multi-Layer, Filler wire
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-74541 (URN)10.1016/j.optlastec.2019.105798 (DOI)000491217800032 ()2-s2.0-85072045298 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-20 (johcin)

Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2019-11-06Bibliographically approved
Bunaziv, I., Wenner, S., Ren, X., Frostevarg, J., Kaplan, A. F. .. & Akselsen, O. M. (2020). Filler metal distribution and processing stability in laser-arc hybrid welding of thick HSLA steel. Journal of Manufacturing Processes, 54, 228-239
Open this publication in new window or tab >>Filler metal distribution and processing stability in laser-arc hybrid welding of thick HSLA steel
Show others...
2020 (English)In: Journal of Manufacturing Processes, ISSN 1526-6125, Vol. 54, p. 228-239Article in journal (Refereed) Published
Abstract [en]

Welds made by high power laser beam have deep and narrow geometry. Addition of filler wire by the arc source, forming the laser-arc hybrid welding (LAHW) process, is very important to obtain required mechanical properties. Distribution of molten wire throughout the entire weld depth is of concern since it tends to have low transportation ability to the root. Accurate identification of filler metal distribution is very challenging. Metal-cored wires can provide high density of non-metallic inclusions (NMIs) which are important for acicular ferrite nucleation. Accurate filler distribution can be recognized based on statistical characterization of NMIs in the weld. In the present study, it was found that the amount of filler metal decreased linearly towards the root. The filler metal tends to accumulate in the upper part of the weld and has a steep decrease at 45–55 % depth which also has wavy pattern based on longitudinal cuts. Substantial hardness variation in longitudinal direction was observed, where in the root values can reach > 300 HV. Excessive porosity was generated at 75 % depth due to unstable and turbulent melt flow based on morphology of prior austenite grains. The delicate balance of process parameters is important factor for both process stability and filler metal distribution.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Laser-arc hybrid welding, High strength steel, Thick steel, Non-metallic inclusions, Filler metal distribution, Microstructure, Mechanical properties
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-78209 (URN)10.1016/j.jmapro.2020.02.048 (DOI)2-s2.0-85081159978 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-03-25 (alebob)

Available from: 2020-03-25 Created: 2020-03-25 Last updated: 2020-03-25Bibliographically approved
Näsström, J., Brueckner, F. & Kaplan, A. F. .. (2020). Imperfections in narrow gap multi-layer welding: Potential causes and countermeasures. Optics and lasers in engineering, 129, Article ID 106011.
Open this publication in new window or tab >>Imperfections in narrow gap multi-layer welding: Potential causes and countermeasures
2020 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 129, article id 106011Article in journal (Refereed) Published
Abstract [en]

Narrow Gap Multi-Layer Welding (NGMLW) using a laser as the main heat source and metal wire for material addition has been a growing topic of interest in the last decade. This is in part due to its potential for joining much thicker sheets of steel than what is usually considered possible when using autogenous laser welding. The process has shown great potential but improvements can still be made, e.g. through increased process control to decrease welding imperfections. Using closed-loop control, where the process is continuously monitored and regulated automatically, can help to account for variations during manufacturing. However, achieving functional closed loop control can be challenging due to limitations in data gathering and processing speeds. Important initial steps include identifying what data can be useful and how frequently this data has to be recorded. Too much data takes too long to process while too little causes risks of missing important details. In this study, 20 mm thick X80 pipeline steel sheets are joined together using this multi-layer approach; the samples are examined using 3D scanning and Computed Tomography (CT) analysis and the process is observed using High-Speed Imaging (HSI). The quality of the welded joint and welding imperfections are discussed and potential points of formation are identified. Suggestions on how to mitigate imperfections to improve the quality of the welded joint are presented, including the potential to use camera imaging for closed-loop process control and additional industrial uses of the HSI footage.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Narrow gap multi-layer welding (NGMLW), Laser welding, Narrow gap, High-speed imaging, Porosity, Cavities
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-74542 (URN)10.1016/j.optlaseng.2020.106011 (DOI)000530024400020 ()
Note

Validerad;2020;Nivå 2;2020-02-25 (alebob)

Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2020-05-28Bibliographically approved
Prasad, H. S., Brueckner, F., Volpp, J. & Kaplan, A. F. H. (2020). Laser metal deposition of copper on diverse metals using green laser sources. The International Journal of Advanced Manufacturing Technology, 107(3-4), 1559-1568
Open this publication in new window or tab >>Laser metal deposition of copper on diverse metals using green laser sources
2020 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 107, no 3-4, p. 1559-1568Article in journal (Refereed) Published
Abstract [en]

Green laser sources are advantageous in the processing of copper due to the increase of absorptivity compared with more commonly available infrared lasers. Laser metal deposition of copper with a green laser onto various substrate metals namely copper, aluminium, steel and titanium alloy was carried out and observed through high-speed imaging. The effects of process parameters such as laser power, cladding speed and powder feed rate, and material attributes such as absorptivity, surface conditions and thermal conductivity are tied together to explain the size and geometry of the melt pool as well as the fraction of the power used for melting material. The copper substrate has the smallest melt pool with a high angle, followed by aluminium, steel and titanium alloy. The incorporation times for powder grains in the melt pools vary based on the substrate materials. Its dependency on material properties, including surface tension forces, melting temperatures and material density, is discussed. Oxide skins present on melt pools can affect powder incorporation, most significantly on the aluminium substrate. The lower limits of the fraction of power irradiated on the surface used purely for melting were calculated to be 0.73%, 2.94%, 5.95% and 9.78% for the copper, aluminium, steel and titanium alloy substrates, respectively, showing a strong dependence on thermal conductivity of the substrate material. For a copper wall built, the fraction was 2.66%, much higher than a single clad on a copper substrate, due to reduced workpiece heating. The results of this paper can be transferred to other metals with low absorptivity such as gold.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Copper, Laser Metal Deposition, Additive Manufacturing, High Speed Imaging, Multi-material, Green 515 nm laser, Directed Energy Deposition, Absorptivity, Powder grain incorporation, LMD, DED
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73753 (URN)10.1007/s00170-020-05117-z (DOI)000521121600003 ()2-s2.0-85081542493 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-04-23 (johcin)

Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2020-04-23Bibliographically approved
Hauser, T., Breese, P. P., Kamps, T., Heinze, C., Volpp, J. & Kaplan, A. F. .. (2020). Material transitions within multi-material laser deposited intermetallic Iron Aluminides. Additive Manufacturing, 34, Article ID 101242.
Open this publication in new window or tab >>Material transitions within multi-material laser deposited intermetallic Iron Aluminides
Show others...
2020 (English)In: Additive Manufacturing, ISSN 2214-8604, Vol. 34, article id 101242Article in journal (Refereed) Published
Abstract [en]

Laser Metal Deposition is a near-net-shape processing technology, which allows remarkable freedom in multi-material processing. In the present work, the multi-material processing of two intermetallic iron aluminides, Fe28Al(at.%) and Fe30Al5Ti0.7B(at.%), was investigated. It has been shown that multi-material processing of the two alloys via discrete as well as via gradual material transition is possible without any cracks for manufacturing small cubes. Cross-sections of manufactured parts and tracks showed that a preheating temperature of at least 400 °C is necessary to process crack free samples. EDX-analyses indicated that if a discrete material transition is required in multi-material processing, the material transition should be implemented in the vertical build-up direction because the mixing zone in this direction is significantly smaller than the mixing zone in the horizontal direction. Due to the stronger mixing effects in the horizontal direction, a gradual material transition by a linear progression should be implemented in this direction rather than in the vertical direction. The mixing effects are mainly caused by melt flow, while diffusion effects can be neglected.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Additive Manufacturing, Multi-material processing, Direct Energy Deposition, Laser Metal Deposition, Functionally Graded Material
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-78716 (URN)10.1016/j.addma.2020.101242 (DOI)2-s2.0-85084494684 (Scopus ID)
Available from: 2020-04-29 Created: 2020-04-29 Last updated: 2020-05-26
Dewi, H. S., Fischer, A., Volpp, J., Niendorf, T. & Kaplan, A. F. .. (2020). Microstructure and mechanical properties of laser surface treated 44MnSiVS6 microalloyed steel. Optics and Laser Technology, 127, Article ID 106139.
Open this publication in new window or tab >>Microstructure and mechanical properties of laser surface treated 44MnSiVS6 microalloyed steel
Show others...
2020 (English)In: Optics and Laser Technology, ISSN 0030-3992, E-ISSN 1879-2545, Vol. 127, article id 106139Article in journal (Refereed) Published
Abstract [en]

Fatigue property improvement for automotive components such as crankshafts can be achieved through material selection and tailored surface design. Microalloyed steels are of high interest for automotive applications due to their balanced properties, excellent hardenability and good machinability. Lasers facilitate efficient and precise surface processing and understanding the laser-material-property interrelationships is the key to process optimisation. This work examines microstructural development during laser surface treatment of 44MnSiVS6 microalloyed steel and the resulting mechanical properties. Laser beam shaping techniques are employed to evaluate the impact of beam shaping on the process. It revealed that ferrite structures remain in the treated area surrounded by martensite due to insufficient heating and dwell time of carbon diffusion.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Laser surface treatment, 44MnSiVS6, Laser beam shaping, Microalloyed steel, Phase transformation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-77853 (URN)10.1016/j.optlastec.2020.106139 (DOI)000523646800033 ()
Note

Validerad;2020;Nivå 2;2020-04-21 (alebob)

Available from: 2020-02-25 Created: 2020-02-25 Last updated: 2020-04-21Bibliographically approved
Moradi, M., Meiabadi, S. & Kaplan, A. (2019). 3D Printed Parts with Honeycomb Internal Pattern by Fused Deposition Modelling: Experimental Characterization and Production Optimization. Metals and Materials International, 25(5), 1312-1325
Open this publication in new window or tab >>3D Printed Parts with Honeycomb Internal Pattern by Fused Deposition Modelling: Experimental Characterization and Production Optimization
2019 (English)In: Metals and Materials International, ISSN 1598-9623, E-ISSN 2005-4149, Vol. 25, no 5, p. 1312-1325Article in journal (Refereed) Published
Abstract [en]

In the present study additive manufacturing of Polylactic acid by fused deposition modeling were investigated based on statistical analysis. The honeycomb internal pattern was employed to build inside of specimens due to its remarkable capability to resist mechanical loads. Simplify 3D was utilized to slice the 3D model and to adjust fixed parameters. Layer thickness, infill percentage, and extruder temperature were considered as controlled variables, while maximum failure load (N), elongation at break (mm), part weight (g), and build time (min) were selected as output responses and analysed by response surface method. Analysis of variance results identified layer thickness as the major controlled variable for all responses. Interaction of infill percentage and extruder temperature had a significant influence on elongation at break and therefore, tough fracture of printed parts. The input parameters were optimized to materialize tow criteria; the first one was to rise maximum failure load and the second was to attain tough fracture and lessen build time and part weight at a time. Optimal solutions were examined by experimental fabrication to evaluate the efficiency of the optimization method. There was a good agreement between empirical results and response surface method predictions which confirmed the reliability of predictive models. The optimal setting to fulfill the first criterion could bring on a specimen with more than 1500 (N) maximum failure load and less than 9 (g) weight.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
3D printing, Fused deposition modelling, Mechanical properties, Part weight, Response surface method
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73719 (URN)10.1007/s12540-019-00272-9 (DOI)000480764700019 ()2-s2.0-85070723837 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-30 (johcin)

Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-08-30Bibliographically approved
Moradi, M., Arabi, H. & Kaplan, A. (2019). An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 41(10), Article ID 434.
Open this publication in new window or tab >>An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment
2019 (English)In: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 41, no 10, article id 434Article in journal (Refereed) Published
Abstract [en]

This study investigated the ability of the continuous wave diode laser surface hardening of AISI 410 martensitic stainless steel with a maximum power of 1600 W. Variable process parameters scanning speed (4–7 mm/s), laser power (1200–1600 W) and stand-off distance (65–75 mm) were considered in this study. Microhardness, the geometry of hardened layer (depth and width), microhardness deviation from the base metal microhardness (MHD), microstructure analysis of the laser-hardened zone through optical microscopy and field emission scanning electron microscopy and percentage of the ferrite phase in AISI 410 microstructure by using Clemex software were considered as process output responses. Results confirmed that by increasing the laser power and reducing the scanning speed, the surface hardness and the depth of hardness increase. It is also revealed the width of the hardened area increases by enhancing stand-off distance and reducing the laser power. Maximum hardness of 630 HV0.3 with 2.2 mm depth is obtained. Also, the furnace hardening heat treatment is compared with the laser hardening process. Microstructure, microhardness, and impact tests of the two processes are compared. Results showed that the hardness of the diode laser is 1.4 times the hardness of the furnace hardening heat treatment.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Laser surface hardening, Diode laser, Microhardness, AISI 410 martensitic stainless steel, Microhardness deviation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-76247 (URN)10.1007/s40430-019-1925-2 (DOI)000486507800004 ()2-s2.0-85073070504 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-10-04 (johcin)

Available from: 2019-10-04 Created: 2019-10-04 Last updated: 2019-10-21Bibliographically approved
Bunaziv, I., Akselsen, O., Frostevarg, J. & Kaplan, A. (2019). Application of laser-arc hybrid welding of steel for low-temperature service. The International Journal of Advanced Manufacturing Technology, 102(5-8), 2601-2613
Open this publication in new window or tab >>Application of laser-arc hybrid welding of steel for low-temperature service
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 102, no 5-8, p. 2601-2613Article in journal (Refereed) Published
Abstract [en]

Laser-arc hybrid welding (LAHW) is more often used in shipbuilding and oil and gas industries in recent years. Its popularity arises due to many advantages compared to conventional arc welding processes. The laser beam source is used to achieve much higher penetration depths. By adding filler wire to the process area, by means of an arc source, the mechanical properties can be improved, e.g. higher toughness at low temperatures. Therefore, LAHW is a perspective process for low-temperature service. Applicability of LAHW is under concern due to process stability and mechanical properties related to heterogeneous filler wire distribution through the whole weld metal in deep and narrow joints. This can cause reduced mechanical properties in the weld root as well as problems with solidification cracking. The fast cooling rate in the root provides hard and brittle microconstituents lowering toughness at low temperatures. Numerical simulations and experimental observations showed that an increase in heat input from the laser beam is an effective way to reduce the cooling rate, which is also possible by applying preheating.

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Laser beam, Hybrid welding, Microstructure, Toughness, Numerical simulation
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73054 (URN)10.1007/s00170-019-03304-1 (DOI)000469002200116 ()2-s2.0-85061037205 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-20 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-06-20Bibliographically approved
Bunaziv, I., Akselsen, O. M., Frostevarg, J. & Kaplan, A. (2019). Correction to: Application of laser-arc hybrid welding of steel for low-temperature service [Letter to the editor]. The International Journal of Advanced Manufacturing Technology, 102(5-8), 2615-2615
Open this publication in new window or tab >>Correction to: Application of laser-arc hybrid welding of steel for low-temperature service
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 102, no 5-8, p. 2615-2615Article in journal, Letter (Other academic) Published
Abstract [en]

The original version of this article contained several mistakes. Due to technical problems at the typesetter, author corrections were not carried out. The original article has been corrected.

Place, publisher, year, edition, pages
Springer, 2019
Identifiers
urn:nbn:se:ltu:diva-73409 (URN)10.1007/s00170-019-03536-1 (DOI)
Note

Erratum in: The International Journal of Advanced Manufacturing Technology, vol. 102, iss. 5-8, p. 2601-2613, DOI: 10.1007/s00170-019-03304-1

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2020-05-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3569-6795

Search in DiVA

Show all publications