Effect of energy input on the microstructure and properties of butt joints in DP1000 steel laser welding

Wang, Jinfeng; Yang, Lijun; Sun, Mingsheng; Liu, Tong; Li, Huan

doi:10.1016/j.matdes.2015.11.006

Cited by 74 publications

(45 citation statements)

References 19 publications

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“…Zhao et al studied how laser welding speed affects the microstructure and properties of DP steels of 600, 800, and 1000 MPa grades; they concluded that a linear relationship existed between the carbon equivalent and the hardness of the fusion zone [25]. Wang et al studied laserwelded joints of DP1000 steel, and concluded that they were softened by the tempering and softening of pre-existing martensite and by carbide precipitation [26,27]. Resistance spot-welded DP1000 was studied by Chabok et al, who found that double pulse welding results in a softer HAZ [28].…”

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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“…These properties guarantee the strength at still sufficient formability of safety car body parts made of TWBs using deep drawing process. The joining of sheets in TWBs is usually done by fibre laser welding because of excellent beam quality and high brightness of fibre lasers, high power, deep penetration, low beam divergence, high plug efficiency, and compact size coupled with flexible beam delivery [6,8,[17][18][19][20][21]. Low heat input is an important characteristic of laser welding, and it is the consequence of small fusion zone (FZ) and heat affected zone (HAZ) and the lower cost and higher flexibility compared to other welding methods.…”

Section: Introductionmentioning

confidence: 99%

Microstructural characteristics of fibre laser welded joint of dual phase steel with complex phase steel

Švec¹,

Schrek²,

Dománková³

2018

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Microstructures in the sub-zones of butt joint consisting of dual phase DP980 steel and complex phase CP780 steel with a thickness of 1.5 mm welded using fibre laser process were evaluated. The microstructure in the fusion zone was built of an approximately equal portion of martensite and lower bainite. In both coarse-grained heat affected zones near DP980 and CP780 steel dominant presence of lath martensite and a minor portion of lower bainite were observed. Similar microstructures were created in both fine-grained heat affected zone near DP980 and near CP780 steel but with the presence of ferrite and tempered martensite in region heated to lower peak temperatures. Mainly M3C carbides precipitated in lower bainite, and mostly MX carbonitrides precipitated in martensite. Created microstructures corresponded with microhardness profile across the joint. The highest microhardness of 476 HV0.1 was measured in the coarse-grained region of the heat affected zone near DP980 steel with a high portion of martensite.

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“…1517) The similar result was also observed in the laser welding of DP1000 welding joint. 18) Therefore, the evolution of fusion zone microstructure of DP1180-DP590 welded joint with the increase of input power is: finer LM + B ¼ coarse LM + B + Baxial. With finer lath martensite and bainite formed in fusion zone of DP1180-DP590 welded joint, the interfacial cohesion and plasticity of the fusion zone was improved, suppressed the martensite cracking in the fusion zone.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Microstructure, Fracture Mode and Formability of Ultra-High-Strength DP1180/DP590 Tailor Welded Blanks

et al. 2019

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This paper investigated phase transformation and fracture modes in formability test of dissimilar ultra high strength DP1180-DP590 tailor welded blanks. The welded joints with full penetration were obtained by increasing input power.The fusion zone was mainly consisted of lath martensite (LM), bainite (B) and retained austenite (£). With the increase of input power, microstructure evolution in fusion zone is: finer LM + B ¼ coarse LM + B + B axial (B axial represents bainite formed in axial zone). And with finner martensite and bainite dispersed, interfacial cohesion and plasticity was improved and phases were elongated and extensively deformed, which resulted in the transition of fracture modes in formability test. Furthermore, the formability of TWBs achieved superior cupping height, and increased by 20.4% compared with the specimen cracked in fusion zone. [

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Effect of energy input on the microstructure and properties of butt joints in DP1000 steel laser welding

Cited by 74 publications

References 19 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

Microstructural characteristics of fibre laser welded joint of dual phase steel with complex phase steel

Comparison of Microstructure, Fracture Mode and Formability of Ultra-High-Strength DP1180/DP590 Tailor Welded Blanks

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