Softening Kinetics in the Subcritical Heat-Affected Zone of Dual-Phase Steel Welds

Biro, E.; McDermid, Joseph R.; Embury, J.D.; Zhou, Y.

doi:10.1007/s11661-010-0323-2

Cited by 95 publications

(62 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Tempering of martensite is controlled by diffusion of alloying elements in the hierarchical structure of martensite. The mechanisms and kinetics of martensite tempering has been extensively reported elsewhere, 3,4) and Part I of this study has studied the modeling of tempering kinetics. 5) Tempering of martensite results in the reduction of hardness.…”

Section: Introductionmentioning

confidence: 99%

“…The magnitude of the hardness drop depends on the extent of HAZ tempering, and welding parameters, such as the maximum local temperature during welding. [3][4][5][6] In high strength steels, such as DP590, 6) there is minimal HAZ softening and the HAZ is not considered as separate area of elements in FEA modeling. However, in higher strength AHSS containing high volume fraction of martensite there is significant martensite tempering in the HAZ with large associated hardness changes across the weld.…”

Section: Introductionmentioning

confidence: 99%

“…M1500) with 100% volume fraction of martensite show the highest HAZ softening, and the extent of softening depends on chemical composition. 3,4) Recently, FEA modeling of full car crash or components include a separate set of elements representing HAZ properties. Previously, the ratio of the strength of elements making up the weld HAZ compared to those representing the base material were calculated from hardness values to scale the material properties.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Advanced Characterization of HAZ Softening of AHSS for Crash Modeling

2017

View full text Add to dashboard Cite

Advanced characterization of the mechanical properties in the softened HAZ is vital for designing welded AHSS components, as it is needed to predict post-weld performance, such as during crash. The weld heat affected zone (HAZ) of advanced high strength steels (AHSS) containing significant volume fractions of martensite exhibit considerable softening because of tempering effects. HAZ softening of two AHSS; Usibor 1500 (press hardening steel) and M1500 with nominal ultimate tensile strength (UTS) of 1 500 MPa has been characterized in this study. Samples were subjected to various rapid tempering cycles using the Gleeble to simulate the microstructures found in different locations of the sub-critical HAZ. Mechanical properties of simulated weld areas have been measured with different geometries, representing different levels of stress triaxiality. Furthermore, Digital Image Correlation (DIC), to determine fracture strain of HAZ, measured the fracture strain of a spot weld and base metal for Usibor 1500. Uniaxial tensile and notch sample geometries were used to investigate the influence of different strain path. The results show fracture strain is a weak function of strain path for samples that fail in the HAZ, whereas fracture strain of the base material considerably depends on strain path.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Advanced Characterization of HAZ Softening of AHSS for Crash Modeling

2017

View full text Add to dashboard Cite

show abstract

“…Unfortunately, this tempering of martensite cannot be prevented during the resistance spot welding process, because of the continuously decreasing temperature distribution between weld pool and unaffected base material. The main decomposition products of martensite found in the sub-critical HAZ are cementite and ferrite, which cause the typical decrease in material hardness [4,5]. The severeness of HAZ softening is known to be mainly dependent on welding parameters and martensite content: an increase in heat input during welding (e.g.…”

Section: Introductionmentioning

confidence: 99%

Identification of Plasticity Model Parameters of the Heat-Affected Zone in Resistance Spot Welded Martensitic Boron Steel

Eller

Greve

Andres

et al. 2015

KEM

View full text Add to dashboard Cite

A material model is developed that predicts the plastic behavior of fully hardened 22MnB5 base material and the heat-affected zone (HAZ) material found around its corresponding resistance spot welds (RSWs). Main focus will be on an accurate representation of strain fields up to high strains, which is required for subsequent calibration of the fracture behavior of both base material and HAZ. The plastic behavior of the base material is calibrated using standard tensile tests and notched tensile tests and an inverse FEM optimization algorithm. The plastic behavior of the HAZ material is characterized using a specially designed tensile specimen with a HAZ in the gage section. The exact location of the HAZ relative to the center of the RSW is determined using microhardness measurements, which are also used for mapping of the material properties into an FE-model of the specimen. With the parameters of the base material known, and by assuming a linear relation between the hardness and the plasticity model parameters of base material and HAZ, the unknown HAZ parameters are determined using inverse FEM optimization. A coupon specimen with HAZ is used to validate the model at hand.

show abstract

“…HAZ softening is related to cooling rate (heat input), prestrain, DP martensite content and chemical composition, especially Mn, Cr and Mo [5][6][7][8]. The present work studies the effect of different heat inputs (cooling rates) on HAZ softening and its effects on mechanical properties of DP welded joints with GMAW.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and metallurgical properties of DP 1000 steel square butt welded joints with GMAW

Rocha

Machado

Mazzaferro

2014

IJET

View full text Add to dashboard Cite

In this work, Gas Metal Arc Welding (GMAW) was used to study the influence of heat input (i.e. cooling rate) on mechanical/metallurgical properties of square butt welded joints of DP 1000 sheets. The influence of filler metals of different strengths on the mechanical properties of joints was also tested. A significant decrease in hardness was observed in the Heat Affected Zone (HAZ) due to martensite tempering, in regions where peak temperature was close to isotherm AC1 (calculated in 735 o C for these steel); coincidently, fracture in every tensile test occurred in regions where martensite was tempered, even when a wire of less strength was used. It was noticed that the decrease in ultimate tensile and yield strength of base metal was inherent to welding. When minimum heat input was used, deterioration in mechanical properties was less pronounced, once degree of HAZ softening was smaller. Elongation of joints increased with increasing heat input.

show abstract

Softening Kinetics in the Subcritical Heat-Affected Zone of Dual-Phase Steel Welds

Cited by 95 publications

References 11 publications

Advanced Characterization of HAZ Softening of AHSS for Crash Modeling

Advanced Characterization of HAZ Softening of AHSS for Crash Modeling

Identification of Plasticity Model Parameters of the Heat-Affected Zone in Resistance Spot Welded Martensitic Boron Steel

Mechanical and metallurgical properties of DP 1000 steel square butt welded joints with GMAW

Contact Info

Product

Resources

About