| Title |
Relationship Between Variation in Welding Machine Oscillation Frequency and Inclusion Formation Behavior
with Respect to Heat Input Change in HF-ERW |
| Authors |
하정우(Jung-Woo Ha) ; 김성웅(Sung-woong Kim) ; 변우진(Woo-Jin Byeon) ; 손호상(Ho-Sang Shon) |
| DOI |
https://doi.org/10.3365/KJMM.2025.63.9.700 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
High frequency electric resistance welding phenomenon; Oscillation frequency; Peak prominence; Strength of heat input; Welding inclusions |
| Abstract |
In this study, High-Frequency Electric Resistance Welding (HF-ERW) phenomena were
investigated by measuring variations in the oscillation frequency. Changes in welding phenomenon with
welding power involve the formation of a narrow gap and the generation and movement of a bridge. These
consequently affect the length of the current path. The change in the current path length results in a variation in
the resonance oscillation frequency of the high-frequency welding power supply. By analyzing the oscillation
frequency variations, three key characteristic parameters were extracted: Peak Prominence, Strength of Heat
Input, and the number of Detected Peaks. The combination of these three parameters allows the prevailing
welding phenomenon to be identified. A cold weld is indicated when all three parameters exhibit low values.
Normal welding is achieved when the Peak Prominence exceeds a certain threshold value. Within the normal
welding regime, oxidized welding inclusions such as Mn-Si-Al-Ti-Nb-O are formed. Analyses confirmed that as
the heat input increases, the content of Mn and O within these inclusions increases, and trace alloying
elements like Ti and Nb are also additionally oxidized. These changes can be detected by variations in the
slope of the frequency waveform, which reflects the bridge's migration speed. By interpreting changes in
welding phenomena caused by external factors and variations in welding conditions through oscillation
frequency waveform analysis, this research can help enhance HF-ERW weld integrity. |