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BETA
Frostevarg, Jan, Teknologie doktorORCID iD iconorcid.org/0000-0003-4265-1541
Alternative names
Publications (10 of 57) Show all publications
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. 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 (Refereed) 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

The International Journal of Advanced Manufacturing Technology, 102, 5-8, 2601-2613, DOI: 10.1007/s00170-019-03304-1

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-06-20Bibliographically approved
Frostevarg, J., Olsson, R., Powell, J., Palmquist, A. & Brånemark, R. (2019). Formation mechanisms of surfaces for osseointegration on titanium using pulsed laser spattering. Applied Surface Science, 458, 158-169
Open this publication in new window or tab >>Formation mechanisms of surfaces for osseointegration on titanium using pulsed laser spattering
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2019 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 458, p. 158-169Article in journal (Refereed) Published
Abstract [en]

Accelerated bone grow (osseointegration) can be achieved by modifying the surface of medical implants. For this purpose, pulsed lasers can be used to successfully texture such beneficial surfaces on titanium, e.g. a BioHelix™ structure. This surface typically includes ridges and droplets with a size range between 1 and 20 μm. This paper presents the results of an experimental program where a range of laser parameters was used to create different surface textures on titanium substrates, using pulsed laser spattering. The resultant surfaces are analysed by scanning electron microscope and X-ray Micro Computer Tomography. It is shown that optimisation of the laser parameters results in a robust process which produces a surface that has proven to be beneficial for osseointegration. The results are also deeper analysed, explaining how different types of surface are created by the laser-material interaction under different conditions. Further, droplet flight distances and the formation of the spongeous nano-scale surface that characterizes the surface structure depends on very fast cooling and is also evaluated.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Osseointegration, Titanium, Laser, Surface, Spatter, BioHelix
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73791 (URN)10.1016/j.apsusc.2019.04.187 (DOI)000472183900020 ()2-s2.0-85067607616 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-07-09 (johcin)

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-07-09Bibliographically approved
Olsson, R., Powell, J., Palmquist, A., Brånemark, R., Frostevarg, J. & Kaplan, A. (2019). Formation of osseointegrating (bone integrating) surfaces on titanium by laser irradiation. Journal of laser applications, 31(2), Article ID 022508.
Open this publication in new window or tab >>Formation of osseointegrating (bone integrating) surfaces on titanium by laser irradiation
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2019 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 31, no 2, article id 022508Article in journal (Refereed) Published
Abstract [en]

Pulsed lasers can be used to modify the surface of medical implants in order to accelerate bone growth (osseointegration). A surface covered in attached droplets with diameters between 1 and 20 μm is a beneficial surface for rapid osseointegration. This paper presents the results of an experimental program in which a broad range of laser parameters and different atmospheres were used to create different surface textures on titanium substrates, including the desired "attached droplet" topology. The resulting surfaces were analyzed by scanning electron microscopy and micro-computer tomography. The paper explains how different types of surfaces are created by the laser-material interaction under different conditions and focus characteristics. It is shown that optimization of the laser parameters results in a robust process, which produces a surface that is fundamentally different from those created by nonlaser methods.

Place, publisher, year, edition, pages
Laser Institute of America, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-73825 (URN)10.2351/1.5096075 (DOI)2-s2.0-85064218607 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-03 (johcin)

Available from: 2019-05-03 Created: 2019-05-03 Last updated: 2019-06-03Bibliographically approved
Robertson, S., Frostevarg, J., Kaplan, A., Hong, S. M., Kim, J.-H. & Bang, H.-S. (2019). Tailored laser pulse method to manipulate filler wire melt metallurgy from thermal cycles. Paper presented at Proceedings of the International Congress of Applications of Lasers & Electro-Optics (ICALEO® 2018).. Journal of laser applications, 31(2), Article ID 022605.
Open this publication in new window or tab >>Tailored laser pulse method to manipulate filler wire melt metallurgy from thermal cycles
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2019 (English)In: Journal of laser applications, ISSN 1042-346X, E-ISSN 1938-1387, Vol. 31, no 2, article id 022605Article in journal (Refereed) Published
Abstract [en]

A robust method is introduced to simulate and study the filler wire metallurgy for controlled cooling conditions after melting, enabling efficient mapping with prompt analysis of trends. Proposed is a reduced, though representative, process with more controllable conditions. Short lengths of filler wires are preplaced in a cavity, drilled into a base metal sheet. Irradiation by a pulsed laser beam melts the wire to generate a sample nugget. Pulse shaping influences the cooling rate, granting the ability to tailor weldament microstructures. The method is demonstrated for S1100QL steel and undermatched filler wire, to obtain high toughness for processes like laser-arc hybrid welding, where a representative thermal cycle is needed. For high toughness, a controlled amount of acicular ferrite and, in turn, nonmetallic inclusions is desirable. This “snapshot” method has revealed a characteristic histogram of inclusion sizes, for different pulse shapes. Additional information on the thermal cycle can be acquired by employing thermocouples, a pyrometer, or advanced methods like high speed imaging or modeling. The method offers a wide spectrum of variants and applications.

Place, publisher, year, edition, pages
USA: Laser Institute of America, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-75401 (URN)10.2351/1.5096145 (DOI)2-s2.0-85065039863 (Scopus ID)
Conference
Proceedings of the International Congress of Applications of Lasers & Electro-Optics (ICALEO® 2018).
Projects
OptoSteel
Note

Konferensartikel i tidskrift

Available from: 2019-08-06 Created: 2019-08-06 Last updated: 2019-08-13Bibliographically approved
Siva Prasad, H., Frostevarg, J. & Kaplan, A. (2019). The stability of laser welding with an off-axis wire feed. Journal of Materials Processing Technology, 264, 84-90
Open this publication in new window or tab >>The stability of laser welding with an off-axis wire feed
2019 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 264, p. 84-90Article in journal (Refereed) Published
Abstract [en]

The concept using an off-axis filler wire during laser welding is introduced here in order to provide added process robustness considering gap width variations. Its stability is investigated with respect to gap width, welding speeds and powers. Geometry of the welds is analysed by tracing of weld cap edges and joint cross sections, connecting trends to weld parameters. High speed imaging and streak images are used to further study and describe sequences of events, including undercut formation. Formation of imperfections are found to be mainly correlated to wire feed position variations at the surface due to irregular melting of the wire tip.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-70826 (URN)10.1016/j.jmatprotec.2018.09.003 (DOI)000450135400009 ()2-s2.0-85053062410 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-09-21 (svasva)

Available from: 2018-09-11 Created: 2018-09-11 Last updated: 2019-04-24Bibliographically approved
Näsström, J., Frostevarg, J. & Kaplan, A. (2018). Arc formation in narrow gap hot wire laser welding. Welding Journal, 97(6), 171S-178S
Open this publication in new window or tab >>Arc formation in narrow gap hot wire laser welding
2018 (English)In: Welding Journal, ISSN 0043-2296, Vol. 97, no 6, p. 171S-178SArticle in journal (Refereed) Published
Abstract [en]

Many heavy industrial applications, e.g. shipbuilding and offshore, rely on thick-section, high-quality welds. Unfortunately, traditional arc-based techniques are often found wanting due to a limited penetration depth and excessive heat-affected zone. The former is typically solved by having a wide groove filled by multiple weld passes, which is both costly and time consuming. Other processes such as autonomous laser or electron beams can join thick materials, but have disadvantages such as increased hardness and solidification cracks inside the welds. A promising in-between technique to join thick sheets is narrow gap multi layer laser welding (NGMLW), using less filler material while also offering more control of weld properties. This technique is often used with laser scanning optics and cold wire, or a defocused laser and electrically heated wire. This paper investigates the limitations of the latter during NGMLW, mainly using high-speed imaging to directly observe and explain process behavior. Increased deposition rates are wanted, but heating also consequently needs to be increased for proper bead fusion. Arc occurrences are found to be the cause of instabilities. They are observed occasionally even at low voltages, but more frequently at higher outputs, and then are also more disruptive to the process.

Place, publisher, year, edition, pages
American Welding Society, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-70165 (URN)10.29391/2018.97.015 (DOI)000435429400018 ()2-s2.0-8504937533 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-07-26 (inah)

Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2019-06-14Bibliographically approved
Bunaziv, I., Akselsen, O. M., Frostevarg, J. & Kaplan, A. F. .. (2018). Deep penetration fiber laser-arc hybrid welding of thick HSLA steel. Journal of Materials Processing Technology, 256, 216-228
Open this publication in new window or tab >>Deep penetration fiber laser-arc hybrid welding of thick HSLA steel
2018 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 256, p. 216-228Article in journal (Refereed) Published
Abstract [en]

The present investigation addresses laser-arc hybrid welding of 45 mm thick steel with variation in a wide range of process parameters. High volume fraction of acicular ferrite formed in the upper part of the weld metal regardless process parameters. Significantly lower fraction of acicular ferrite was found in the root due to substantially increased cooling rates and the inability to deliver filler wire to this region, resulting in bainite-martensite microstructures in the root. The delivery of filler wire to the root can be enhanced by increasing the air gap between the plates. Higher heat inputs reduce cooling rates in the root which create softer and ductile microstructures, at the expense of a much wider and coarser grained HAZ. The results obtained showed high fusion line and weld metal toughness at low temperature (−50 °C).

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-67696 (URN)10.1016/j.jmatprotec.2018.02.026 (DOI)000431156800021 ()2-s2.0-85042446378 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-02-26 (andbra)

Available from: 2018-02-20 Created: 2018-02-20 Last updated: 2018-06-11Bibliographically approved
Pocorni, J., Powell, J., Frostevarg, J. & Kaplan, A. F. H. (2018). Dynamic laser piercing of thick section metals. Optics and lasers in engineering, 100, 82-89
Open this publication in new window or tab >>Dynamic laser piercing of thick section metals
2018 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 100, p. 82-89Article in journal (Refereed) Published
Abstract [en]

Before a contour can be laser cut the laser first needs to pierce the material. The time taken to achieve piercing should be minimised to optimise productivity. One important aspect of laser piercing is the reliability of the process because industrial laser cutting machines are programmed for the minimum reliable pierce time. In this work piercing experiments were carried out in 15 mm thick stainless steel sheets comparing a stationary laser and a laser which moves along a circular trajectory with varying processing speeds. Results show that circular piercing can decrease the pierce duration by almost half compared to stationary piercing. High speed imaging (HSI) was employed during the piercing process to understand melt behaviour inside the pierce hole. HSI videos show that circular rotation of the laser beam forces melt to eject in opposite direction of the beam movement, while in stationary piercing the melt ejects less efficiently in random directions out of the hole.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Laser cutting, laser piercing, reliability, efficiency, fibre laser, high speed imaging
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-63492 (URN)10.1016/j.optlaseng.2017.07.012 (DOI)000414108700010 ()2-s2.0-85026484330 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-15 (andbra)

Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2019-02-18Bibliographically approved
Frostevarg, J. (2018). Factors affecting weld root morphology in laser keyhole welding (ed.). Optics and lasers in engineering, 101, 89-98
Open this publication in new window or tab >>Factors affecting weld root morphology in laser keyhole welding
2018 (English)In: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 101, p. 89-98Article in journal (Refereed) Published
Abstract [en]

Welding production efficiency is usually optimised if full penetration can be achieved in a single pass. Techniques such as electron and laser beam welding offer deep high speed keyhole welding, especially since multi-kilowatt lasers became available. However, there are limitations for these techniques when considering weld imperfections such as weld cap undercuts, interior porosity or humps at the root. The thickness of sheets during full penetration welding is practically limited by these root humps. The mechanisms behind root morphology formation are not yet satisfactory understood. In this paper root humping is studied by reviewing previous studies and findings and also by sample examination and process observation by high speed imaging. Different process regimes governing root quality are presented, categorized and explained. Even though this study mainly covers laser beam and laser arc hybrid welding, the presented findings can generally be applied full penetration welding in medium to thick sheets, especially the discussion of surface tension effects. As a final result of this analysis, a map of methods to optimise weld root topology is presented.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
urn:nbn:se:ltu:diva-66247 (URN)10.1016/j.optlaseng.2017.10.005 (DOI)000416499200012 ()2-s2.0-85031996479 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-10-25 (andbra)

Available from: 2017-10-25 Created: 2017-10-25 Last updated: 2017-12-14Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4265-1541

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