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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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X-ray diffraction pattern of the welds with different vibration frequencies.
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fig10: X-ray diffraction pattern of the welds with different vibration frequencies.

Mentions: Figure 10 indicates the diffraction pattern of various vibration modes at resonant and subresonant frequencies. The results indicate that the primary phase included the δ-ferrite and the γ-austenite in the 304 stainless steel. The diffracted peak of the γ(111) had the highest intensity without vibration and with vibration. The intensity ratio of γ(111) and γ(200) was about 5 : 1 without vibration. However, the intensity ratio of the γ(111) and γ(200) was 2.5 : 1 at a resonant frequency using an eccentric circulating vibrator. Table 3 shows the examined results of full width at half maximum (FWHM). The width of the FWHM in different crystallographic planes of γ(111), γ(200), γ(220), and δ(110) increases after vibration. Kuo [13] has pointed out that the increment of the FWHM is due to the stacking fault after the simultaneous vibration welding. Hence, the mechanism of stress relief for vibration welding is attributed to formation of the stacking fault.


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)

X-ray diffraction pattern of the welds with different vibration frequencies.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig10: X-ray diffraction pattern of the welds with different vibration frequencies.
Mentions: Figure 10 indicates the diffraction pattern of various vibration modes at resonant and subresonant frequencies. The results indicate that the primary phase included the δ-ferrite and the γ-austenite in the 304 stainless steel. The diffracted peak of the γ(111) had the highest intensity without vibration and with vibration. The intensity ratio of γ(111) and γ(200) was about 5 : 1 without vibration. However, the intensity ratio of the γ(111) and γ(200) was 2.5 : 1 at a resonant frequency using an eccentric circulating vibrator. Table 3 shows the examined results of full width at half maximum (FWHM). The width of the FWHM in different crystallographic planes of γ(111), γ(200), γ(220), and δ(110) increases after vibration. Kuo [13] has pointed out that the increment of the FWHM is due to the stacking fault after the simultaneous vibration welding. Hence, the mechanism of stress relief for vibration welding is attributed to formation of the stacking fault.

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