Laser beam welding of DP980 dual phase steel at high temperatures

Ferreira, Caroline Cristine de Andrade; Braga, Vagner; Siqueira, Rafael Humberto Mota de; Carvalho, Sheila Medeiros de; Lima, Milton Sérgio Fernandes de

doi:10.1016/j.optlastec.2019.105964

Cited by 13 publications

(5 citation statements)

References 6 publications

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“…The mechanical properties of DP steels depend on martensite volume fraction, martensite islands distribution in the ferrite phase, shape and grain sizes and partitioning of stress-strain between two phases [1,2]. DP steel can be welded using a variety of fusion techniques, including resistance spot [3][4][5][6][7], laser beam [8][9][10][11], plasma arc [12][13][14], friction stir [15][16][17][18] and gas metal arc welding. Xia and Biro investigated the effects of heat input on heat affected zone (HAZ) softening [19], which cannot be avoided in DP steels.…”

Section: Introductionmentioning

confidence: 99%

The comparison of gas tungsten arc welding and flux cored arc welding effects on dual phase steel

Abbas

Hamdy²,

Ahmed

2020

Mater. Res. Express

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This work aims to investigate the effects of two welding techniques (gas tungsten arc welding (GTAW) with filler metal ER70S-3 and flux cored arc welding (FCAW) with filler metal E71T1C) on the microstructure and mechanical properties (including softening due to the conversion of martensite into tempered martensite) of DP steels with different martensite volume fractions ranging from 9 to 20%. Microstructure features and the constituents of base metals and heat affected zones of all weldments were examined and analyzed using an optical microscope and a scanning electron microscope integrated with energy-dispersive x-ray spectroscopy. Hardness, tensile, and v-notch impact toughness measurements were also carried out. Visual and radiographic inspection showed that both the FCAW and GTAW techniques produced sound weldments. However, DP steel weldments exhibited softening effects, which led to a decrease in joint efficiency. This decrease were related to transformation of the original martensite into tempered martensite. The results also revealed that the DP steel joints efficiencies are ranged from 85.9 to 87.7% using the FCAW process and ranged from 83.3 to 86% using the GTAW process. The impact toughness of the samples welded by FCAW is higher than the impact toughness of those welded by GTAW due to a higher percentage of acicular ferrite. This information should be valuable in the automotive and other industries, where DP steels are valued for their combination of high strength and ductility, which leads to weight savings and thus to reduced fuel consumption.

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Section: Introductionmentioning

confidence: 99%

The comparison of gas tungsten arc welding and flux cored arc welding effects on dual phase steel

Abbas

Hamdy²,

Ahmed

2020

Mater. Res. Express

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“…Induction heating allows reducing the cooling rate of FZ and HAZ, and provides for the formation of less brittle phases; in particular, bainite. The same method can be used to reduce the amount of martensite in welded joints of steel DP980 [13]. DP 980 is currently a dual phase steel with increased strength applied in the production of car body components.…”

Section: Weldability Of Progressive Steel Sheets For the Automotive Imentioning

confidence: 99%

Properties Evaluation of the Welded Joints Made by Disk Laser

et al. 2021

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The process of laser welding of sheets of HSLA (high-strength low-alloy steel), DP600 (dual-phase steel) and TRIP steels was investigated. A weld was successfully made in a double-sided hot-dip galvanized sheet with a thickness of 0.78–0.81 mm using a laser power of 2 kW per pass without any pretreatment of the weld zone. Microstructure studies revealed the presence of martensitic and ferritic phases in the weld zone, which could be associated with a high rate of its cooling. This made it possible to obtain good strength of the weld, while maintaining sufficient ductility. A relationship between the microstructural features and mechanical properties of welds made in the investigated steels has been established. The highest hardness was found in the alloying region of steels due to the formation of martensite. The hardness test results showed a very narrow soft zone in the heat affected zone (HAZ) adjacent to the weld interface, which does not affect the tensile strength of the weld. The ultimate tensile strength of welds for HSLA steel was 340–450 MPa, for DP600 steel: 580–670 MPa, for TRIP steel: ~700 MPa, respectively, exceeding the strength of base steels.

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“…These features are suitable for the fabrication of automotive body parts. As a result, laser welding has been successfully used in similar and dissimilar joining between different generation AHSSs, such as dual-phase steel welding [4][5][6][7][8], twinning-induced plasticity TWIP steel welding [9,10], QP steel welding [11][12][13], and QP-TWIP steel welding [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Beam Oscillation Amplitude on Microstructure and Mechanical Properties of Small Laser Spot Welded QP980 Steel

Yang,

Li,

et al. 2023

Metals

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In this study, butt welds of QP980 steel were produced using small laser spot (0.1 mm) oscillating welding. The effect of beam oscillation with a circular trajectory on weld morphologies, microstructures, and mechanical properties was characterized. As the oscillating amplitude rose, the energy accumulation range enlarged, and the energy peak value was decreased, leading to the appearance of the cross-section changing from a nail-like shape to a cup-cone-like shape and then to a W-type shape. The weld zone is divided into the fusion zone, inner heat-affected zone, and outer soften zone. The fusion zone and inner heat-affected zone are full of typical lath martensite and have the highest hardness. The soften zone is composed of pre-existing martensite, temper martensite, ferrite, and retained austenite and has the lowest hardness. Compared to laser welding, beam oscillation could reduce the pre-existing block martensite to decompose, leading to a narrower width and higher hardness soften zone. Although the width of the fusion zone and soften zone increases with the oscillation amplitude, all welded samples failed at the base metal with 97% joint efficiency.

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Laser beam welding of DP980 dual phase steel at high temperatures

Cited by 13 publications

References 6 publications

The comparison of gas tungsten arc welding and flux cored arc welding effects on dual phase steel

The comparison of gas tungsten arc welding and flux cored arc welding effects on dual phase steel

Properties Evaluation of the Welded Joints Made by Disk Laser

Effect of Beam Oscillation Amplitude on Microstructure and Mechanical Properties of Small Laser Spot Welded QP980 Steel

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