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Evolution of microstructure and residual stress under various vibration modes in 304 stainless steel welds.

Hsieh CC, Wang PS, Wang JS, Wu W - ScientificWorldJournal (2014)

Bottom Line: The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process.A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency.The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 402, Taiwan.

ABSTRACT
Simultaneous vibration welding of 304 stainless steel was carried out with an eccentric circulating vibrator and a magnetic telescopic vibrator at subresonant (362 Hz and 59.3 Hz) and resonant (376 Hz and 60.9 Hz) frequencies. The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process. During simultaneous vibration welding primary δ -ferrite can be refined and the morphologies of retained δ-ferrite become discontinuous so that δ-ferrite contents decrease. The smallest content of δ-ferrite (5.5%) occurred using the eccentric circulating vibrator. The diffraction intensities decreased and the FWHM widened with both vibration and no vibration. A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency. The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator.

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The amount of the equiaxed grain in the welds.
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fig9: The amount of the equiaxed grain in the welds.

Mentions: On the other hand, vibration can increase the contact possibility at the solid-liquid (S-L) interface and help the supercooling of the liquid to nucleate. Consequently, the nucleation point can be raised with lots of the fine equiaxed grains being formed [13]. Figure 9 shows the number of equiaxed grains per unit area (100 μm2). High quality equiaxed grains mean that the nucleation point is greater, so the grain size becomes smaller. This result indicates that vibration can cause grain refinement of the primary δ-ferrite. But the difference in grain refinement was not obvious in the two vibration modes. The retardation of dendrites using a magnetic telescopic vibrator is better than the level achieved using an eccentric circulating vibrator.


Evolution of microstructure and residual stress under various vibration modes in 304 stainless steel welds.

Hsieh CC, Wang PS, Wang JS, Wu W - ScientificWorldJournal (2014)

The amount of the equiaxed grain in the welds.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3926365&req=5

fig9: The amount of the equiaxed grain in the welds.
Mentions: On the other hand, vibration can increase the contact possibility at the solid-liquid (S-L) interface and help the supercooling of the liquid to nucleate. Consequently, the nucleation point can be raised with lots of the fine equiaxed grains being formed [13]. Figure 9 shows the number of equiaxed grains per unit area (100 μm2). High quality equiaxed grains mean that the nucleation point is greater, so the grain size becomes smaller. This result indicates that vibration can cause grain refinement of the primary δ-ferrite. But the difference in grain refinement was not obvious in the two vibration modes. The retardation of dendrites using a magnetic telescopic vibrator is better than the level achieved using an eccentric circulating vibrator.

Bottom Line: The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process.A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency.The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 402, Taiwan.

ABSTRACT
Simultaneous vibration welding of 304 stainless steel was carried out with an eccentric circulating vibrator and a magnetic telescopic vibrator at subresonant (362 Hz and 59.3 Hz) and resonant (376 Hz and 60.9 Hz) frequencies. The experimental results indicate that the temperature gradient can be increased, accelerating nucleation and causing grain refinement during this process. During simultaneous vibration welding primary δ -ferrite can be refined and the morphologies of retained δ-ferrite become discontinuous so that δ-ferrite contents decrease. The smallest content of δ-ferrite (5.5%) occurred using the eccentric circulating vibrator. The diffraction intensities decreased and the FWHM widened with both vibration and no vibration. A residual stress can obviously be increased, producing an excellent effect on stress relief at a resonant frequency. The stress relief effect with an eccentric circulating vibrator was better than that obtained using a magnetic telescopic vibrator.

Show MeSH