Effect of duty cycle on microstructure and mechanical properties of pulsed GTAW lap joint of Invar

Wang, Hou; Hu, Shengsun; Shen, Junqi; Li, Dalong; Lu, Jiansheng

doi:10.1016/j.jmatprotec.2017.01.008

Cited by 13 publications

(12 citation statements)

References 7 publications

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“…A number of papers can be cited that contain this problem. In the work of Wang Hou et al [4] there is a study of the duty cycle effect (pulse time/total period) on the mechanical properties of overlap welds of Invar alloy (Ni and Fe-based alloy). In the experiments, the authors set the pulse current, the base current, the frequency at 10 Hz and the welding speed at 5 mm/s.…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding

Dutra

Riffel

Silva

et al. 2023

Preprint

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The GTAW welding with pulsed current has been misinterpreted in some classic literature and scientific articles. General conclusions are presented, stating that its use provides greater penetration compared to the use of constant current and that the simple pulsation of the current promotes beneficial metallurgical effects. Therefore, this manuscript presents a critical analysis of this topic and adopts the terminology of thermal pulsation for the situation where the weld undergoes sensitive effects regarding grain orientation during solidification. For comparison purposes, an index called the form factor (ratio between the root width and the face width of the weld bead) is adopted. It is shown that the penetration of a welding with pulsed current can be worse than constant current depending on the formulation of the adopted procedure. Moreover, metallurgical effects on solidification, such as grain orientation breakage, only occur when there is adequate concatenation between the pulsation frequency and the welding speed. Finally, a thermal simulation of the process showed that the pulsation frequency limits the welding speed so that there is an overlap of the molten pool in each current pulse, and continuity of the bead is obtained at the root. For frequencies of 1Hz and 2.5 Hz, the limit welding speed was 3.3 mm/s and 4.1 mm/s, respectively.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding

Dutra

Riffel

Silva

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Temperature gradients give rise to a material with mechanical and microstructural properties that can vary considerably over the weldment dimensions. Wang et al (2017) obtained different hardness values across the FZ and the HAZ due to the formation of columnar grains in the FZ.…”

Section: Introductionmentioning

confidence: 96%

Characterization of the Gas Tungsten Arc Welding (GTAW) joint of Armco iron nanostructured by Equal-Channel Angular Pressing (ECAP)

Serrano-Muñoz

Комиссаров

Mejı́a

et al. 2021

Journal of Materials Processing Technology

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“…ASTM F1684 is known to have a low coefficient of thermal expansion (CTE) from room temperature to around Curie temperature (230 • C), and excellent mechanical properties in cryogenic environments. Due to these characteristics, it is widely used as a highreliability and high-precision material, in space equipment, precision equipment, and LNG tanks [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Wang et al performed lap joint welding by applying the GTAW welding method to Invar of 0.7 mm and 1.0 mm thickness and compared its microstructure, hardness, and shear tensile characteristics depending on duty cycle size. As a result, the tensile shear force is directly proportional to the duty cycle, and the maximum tensile shear force is 4425 N [11]. Kim et al applied fiber laser welding using cold wire to a cross-shaped Invar of 1.5 mm and 3.0 mm thickness.…”

Section: Introductionmentioning

confidence: 99%

A Study on Lap Joint Welding of Thin Plate ASTM F1684 Using Fiber Laser Welding

Kim

et al. 2021

Processes

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The International Maritime Organization (IMO) has developed stricter regulations on emission standards for sulfur oxides, etc., and the demand for Liquefied Natural Gas (LNG) is increasing as an alternative to satisfy these standards. This study relates to fiber laser welding, an approach which offers high-speed welding and low welding deformation for ASTM F1684, which has a low coefficient of thermal expansion (CTE) even in a cryogenic environment. In this study, through three preliminary experiments using 0.25 mm thick Invar, the conditions required to secure sufficient penetration depth and back bead were identified. Through the cross-sectional observation analysis, the welding conditions without defects were identified and the trend of penetration shape according to increasing welding speed was identified. Following a lap joint laser welding experiment under the secured conditions, the mechanical properties were evaluated through the shear strength test and the heat influence range of a fiber laser was identified through the temperature measurement of a welding part. As a result, it was confirmed that the shear strength of the lap joint laser welding part was 86.8% that of the base metal.

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Effect of duty cycle on microstructure and mechanical properties of pulsed GTAW lap joint of Invar

Cited by 13 publications

References 7 publications

WITHDRAWN: A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding

WITHDRAWN: A Contribution to the Analysis of the Effects of Pulsed Current in GTAW Welding

Characterization of the Gas Tungsten Arc Welding (GTAW) joint of Armco iron nanostructured by Equal-Channel Angular Pressing (ECAP)

A Study on Lap Joint Welding of Thin Plate ASTM F1684 Using Fiber Laser Welding

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