Effect of Arc Length on Oxygen Content and Mechanical Properties of Weld Metal during Pulsed GMAW
2. Experimental Method
3. Results and Discussion
3.1. Effect of Arc Length on Oxygen Content of Weld Metal
3.2. Effect of Arc Length on Mechanical Properties of Weld Metal
- As the arc length raised from 2.9 mm to 9.2 mm, the transfer time increased but the droplet size diminished. Meanwhile, the oxidation reacted more completely in the droplet transfer zone, and the oxygen content of the weld metal increased significantly from 217 ppm to 372 ppm.
- When the arc length increased from 2.9 mm to 9.2 mm, the tensile strength of the weld metal reduced from 781 MPa to 729 MPa but the −40 °C impact energy heightened from 79 J to 116 J.
- Due to the longer arc, the proportion of AF in the microstructure decreased, but the proportion of LB and GB decreased. With the rise of arc length, the cleavage step morphology decreased in the impact fracture however, the dimples increased.
- The more oxygen content of weld metal was useful for the formation of inclusions in impact fracture. Inclusions promoted the nucleation of acicular ferrite and dimples, contributing to the growth of plasticity and toughness of weld metal.
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
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|Welding Parameters||Test 1||Test 2||Test 3||Test 4|
|Contact tube-to-work distance, mm||20|
|Pulse peak current, A||525|
|Pulse peak current time, ms||1.6|
|Pulse base current, A||28|
|Pulse base current time, ms||9||8.2||7.4||6.6|
|Arc shielding gas||82% Ar + 18% CO2|
|Flow rate of arc shielding gas, L·min−1||18|
|Speed of wire feed, m·min−1||4|
|Welding speed, mm·s−1||4|
|Arc length, mm||2.9||4.5||6.5||9.2|
|Average current, A||122||130||139||149|
|Average voltage, V||22.4||25.9||28.1||31.3|
|Arc Length La/mm||C||Si||Mn||Cu||Cr||Ni||Mo||Al||Ti|
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Xu, J.; Zhou, X.; Zhu, D. Effect of Arc Length on Oxygen Content and Mechanical Properties of Weld Metal during Pulsed GMAW. Crystals 2022, 12, 176. https://doi.org/10.3390/cryst12020176
Xu J, Zhou X, Zhu D. Effect of Arc Length on Oxygen Content and Mechanical Properties of Weld Metal during Pulsed GMAW. Crystals. 2022; 12(2):176. https://doi.org/10.3390/cryst12020176Chicago/Turabian Style
Xu, Jiachen, Xiaoxiao Zhou, and Dawei Zhu. 2022. "Effect of Arc Length on Oxygen Content and Mechanical Properties of Weld Metal during Pulsed GMAW" Crystals 12, no. 2: 176. https://doi.org/10.3390/cryst12020176