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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 relationship between the vibration frequency and the hardness value.
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fig15: The relationship between the vibration frequency and the hardness value.

Mentions: Figure 15 shows the relationship between vibration frequency and hardness after vibration welding. The hardness value without vibration was 193.8 Hv. Hardness values at subresonant and resonant frequencies using a magnetic telescopic vibrator (TX-VSR) were 198.6 Hv and 207.2 Hv, respectively. The hardness value at subresonant and resonant frequencies using eccentric circulating vibrator (Meta-Lax) were 199 Hv and 209.7 Hv, respectively. The above results indicate that the hardness had its lowest value without vibration and that the highest values were achieved at a resonant frequency in all conditions. The hardness value can be increased at a subresonant and a resonant frequency by about 2.5% and 7.3%, respectively. The increment of the hardness is due to grain refinement during vibration welding. Lu et al. [9] reported that vibration welding can raise the nucleation sites, leading to grain refinement and increasing the mechanical properties at the same time. On the other hand, the hardness values increase with the decrease of δ-ferrite content (as in Section 3.4) when the vibration frequencies are raised because the δ-ferrite is softer than γ-phase.


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 relationship between the vibration frequency and the hardness value.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig15: The relationship between the vibration frequency and the hardness value.
Mentions: Figure 15 shows the relationship between vibration frequency and hardness after vibration welding. The hardness value without vibration was 193.8 Hv. Hardness values at subresonant and resonant frequencies using a magnetic telescopic vibrator (TX-VSR) were 198.6 Hv and 207.2 Hv, respectively. The hardness value at subresonant and resonant frequencies using eccentric circulating vibrator (Meta-Lax) were 199 Hv and 209.7 Hv, respectively. The above results indicate that the hardness had its lowest value without vibration and that the highest values were achieved at a resonant frequency in all conditions. The hardness value can be increased at a subresonant and a resonant frequency by about 2.5% and 7.3%, respectively. The increment of the hardness is due to grain refinement during vibration welding. Lu et al. [9] reported that vibration welding can raise the nucleation sites, leading to grain refinement and increasing the mechanical properties at the same time. On the other hand, the hardness values increase with the decrease of δ-ferrite content (as in Section 3.4) when the vibration frequencies are raised because the δ-ferrite is softer than γ-phase.

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