Short thermal cycle treatment with laser of vanadium microalloyed steels

Dewi, Handika Sandra; Volpp, Jöerg; Kaplan, Alexander

doi:10.1016/j.jmapro.2020.06.036

Cited by 7 publications

(5 citation statements)

References 47 publications

(56 reference statements)

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“…The treated area is defined by the area where martensitic transformation occurred, which was shown to be closely related to the hardness drop identified in comparative hardness measurements. 8,19 Accordingly, the depth of the treated area was measured every 300 μm from the leftmost to the rightmost of the treated area and the standard deviation of these measurements were calculated using the STDEV formula in MS EXCEL for each specimen.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the integration of this region represents the total energy input distribution on a specimen's cross section.For the evaluation of the treated surface of the material, the specimens' cross sections were taken from the track and prepared using a 3% Nital solution. The treated area is defined by the area where martensitic transformation occurred, which was shown to be closely related to the hardness drop identified in comparative hardness measurements 8,19. Accordingly, the depth of the treated area was measured every 300 μm from the leftmost to the rightmost of the treated…”

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confidence: 99%

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Impact of laser beam oscillation strategies on surface treatment of microalloyed steel

Dewi

Volpp

2020

Journal of Laser Applications

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The depth homogeneity of laser-treated zones is one possible factor to define the quality and efficacy of altered mechanical properties in materials. For instance, half-rounded cross-sectional shapes of laser hardened zones using Gaussian beams provide dissimilar hardened depth in the edges and center of the treated area. This means that the in-depth distribution of compressive residual stress varies between the edges and the center of the hardened area. Nonhomogeneity of compressive residual stress distributions can inhibit fatigue properties and can lead to product failure. The utilization of oscillated laser beams has been proven to improve the welding efficiency and energy input distribution to the material, which promises achieving a homogeneous depth of laser-treated zones in hardening applications. Therefore, this work examines the influence of triangular, square, and circular beam oscillation strategies on the energy input distribution during the process and the geometry of the laser-treated zones on microalloyed steel. Laser beam pathways were assembled using a vector graphic editor to visualize the energy distribution from each oscillation strategy. Cross section images of the hardened tracks were taken and related to the thermal energy input profiles. It was revealed that each oscillation strategy demonstrates characteristic temporal and spatial thermal energy input distribution, influencing the geometry of the hardened zone. The circular oscillation strategy produced a widely constant depth in contrary to the triangular and square beam oscillation due to its characteristic energy distribution that allows homogeneous heat dissemination in the material. This confirms that the laser beam oscillation strategy can tailor the energy input distribution to optimize the processing outcome.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

Impact of laser beam oscillation strategies on surface treatment of microalloyed steel

Dewi

Volpp

2020

Journal of Laser Applications

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“…Many studies have shown that niobium is one of the most effective alloying elements used to strengthen microalloyed steels, by not only retarding recrystallization and growth of ferrite grains but also contribute solid solution strengthening by precipitate into ferrite in the form of Nb (C, N) (Cao et al, 2007;Chen et al, 2013). Vanadium, on the other hand, is almost entirely soluble in the austenite phase and contributes to the increase in strength by precipitation in the form of V (C, N) during the austenite ferrite transformation (Baker, 2009;Dewi et al, 2020;Lagneborg et al, 1999;Singh et al, 2020). Studies show that titanium is used for the precipitation hardening mechanism and sulphide shape control instead of grain refinement.…”

Section: Introductionmentioning

confidence: 99%

Production of Nanostructured Fasteners with High Shear and Fatigue Strength for Using in Aircraft Components

GÜRBÜZ,

TAŞKIN

2023

Journal of Aviation

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Multi-axis forging (MAF) and cyclic heat treatment are among the most widely used and easy to apply grain refinement methods. In this study, microalloyed steel samples were first subjected to MAF treatments at 880° C. Microstructural analysis showed that the average grain size, which was 13.2 µm initially, decreased to 11.2 µm application of the MAF. As a second grain refinement technique, cyclic heat treatment was used. Samples were subjected to 1, 3, 5, 7 and 10 cyclic quenching. With this method, it was observed that the average grain size decreased to 2,3 µm. The mechanical tests showed that second MAF process increased the yield and tensile strength of the material about %16 while decrease the elongation only by %2. These tests also presented cyclic quenching increase tensile strength of the samples after first application.

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“…Heating and cooling rates of the material can exceed >1000 K/s [10], which is comparably high (e.g., arc welding 8-20 K/s [11]). Often, microstructural developments are well explained for slow heating and cooling, but there is a lack of understanding during such rapid processes, e.g., Dewi et al [12] showed that rapid cooling after laser hardening can interrupt the formation of martensite and 'freeze' the microstructure to form martensitic ferrite instead.…”

Section: Introductionmentioning

confidence: 99%

Spectral Visualization of Alloy Reactions during Laser Melting

Volpp,

Naesstroem,

Wockenfuss

et al. 2023

Alloys

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Laser materials processing includes rapid heating to possibly high temperatures and rapid cooling of the illuminated materials. The material reactions can show significant deviations from equilibrium processing. During processing of complex materials and material combinations, it is mainly unknown how the materials react and mix. However, it is important to know which chemical elements or compounds are present in the material to define the alloy. In addition, their distribution after rapid cooling needs to be better understood. Therefore, such alloy changes at rapid heating induced by laser illumination were created as pre-placed and pre-mixed powder nuggets. The energy input and the material ratio between the powder components were varied to identify characteristic responses. For the detection of reaction durations and mixing characteristics, the vapor plume content was assumed to contain the necessary information. Spectral measurements of the plume were used to identify indicators about process behaviors. It was seen that the spectral data give indications about the chemical reactions in the melt pool. The reactions of iron ore components with aluminum seem to require laser illumination to finish completely, although the thermite reaction should maintain the chemical reaction, likely due to the required melt mixing that enables the interaction of the reacting partners at all.

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Short thermal cycle treatment with laser of vanadium microalloyed steels

Cited by 7 publications

References 47 publications

Impact of laser beam oscillation strategies on surface treatment of microalloyed steel

Impact of laser beam oscillation strategies on surface treatment of microalloyed steel

Production of Nanostructured Fasteners with High Shear and Fatigue Strength for Using in Aircraft Components

Spectral Visualization of Alloy Reactions during Laser Melting

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