Weldability Evaluation and Microstructure Analysis of Resistance-Spot-Welded High-Mn Steel in Automotive Application

2012 ◽  
Vol 83 (4) ◽  
pp. 352-357 ◽  
Author(s):  
Dulal Chandra Saha ◽  
Sangho Han ◽  
Kwang Geun Chin ◽  
Ildong Choi ◽  
Yeong-Do Park
Keyword(s):  
Microstructure Analysis ◽  
Automotive Application ◽  
Resistance Spot ◽  
Mn Steel ◽  
Spot Welded

scholarly journals Microstructure and Local Mechanical Properties of the Heat-Affected Zone of a Resistance Spot Welded Medium-Mn Steel

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3362
Author(s):  
Manfred Stadler ◽  
Ronald Schnitzer ◽  
Martin Gruber ◽  
Katharina Steineder ◽  
Christina Hofer
Keyword(s):  
Mechanical Properties ◽  
Heat Affected Zone ◽  
Great Influence ◽  
High Strength ◽  
Total Elongation ◽  
Resistance Spot ◽  
Heat Treated ◽  
Medium Mn Steel ◽  
Mn Steel ◽  
Spot Welded

The properties of the heat-affected zone (HAZ) are reported to have a great influence on the mechanical performance of resistance spot welded advanced high strength steels. Therefore, in the present work, the HAZ of a medium-Mn steel is characterized regarding its microstructure and its mechanical properties depending on the distance to the fusion zone (FZ). In order to obtain the local mechanical properties of the HAZ, samples were heat-treated in a joule-heating thermal simulator using different peak temperatures to physically simulate the microstructure of the HAZ. By comparing the microstructure and the hardness of these heat-treated samples and the HAZ, the local peak temperatures within the HAZ could be determined. Subsequently, tensile tests were conducted, and the austenite phase fraction was measured magnetically on the physically simulated HAZ samples in order to determine the local mechanical properties of the HAZ. As verified by energy-dispersive X-ray spectroscopy, peak temperatures above 1200 °C led to a uniform distribution of manganese, resulting in a predominantly martensitic microstructure with high strength and low total elongation after quenching. Below 1100 °C, the diffusion of manganese is restricted, and considerable fractions of austenite remain stable. The austenite fraction increases almost linearly with decreasing peak temperature, which leads to an increase of the total elongation and to a slight decrease in the strength, depending on the distance to the FZ. Temperatures below 700 °C exhibit hardly any effect on the initial microstructure and mechanical properties.

Role of Intercritical Annealing in Enhancing the Cross-Tension Property of Resistance Spot-Welded Medium Mn Steel

2021 ◽  
Vol 30 (2) ◽  
pp. 1259-1269
Author(s):  
Bingge Zhao ◽  
Yuanfang Wang ◽  
Kai Ding ◽  
Guanzhi Wu ◽  
Tao Wei ◽  
...  
Keyword(s):  
Intercritical Annealing ◽  
Resistance Spot ◽  
Medium Mn Steel ◽  
The Cross ◽  
Mn Steel ◽  
Cross Tension ◽  
Spot Welded

Nanoindentation and microstructure analysis of resistance spot welded dual phase steel

2010 ◽  
Vol 64 (2) ◽  
pp. 207-210 ◽  
Author(s):  
V.H. Baltazar Hernandez ◽  
S.K. Panda ◽  
M.L. Kuntz ◽  
Y. Zhou
Keyword(s):  
Dual Phase Steel ◽  
Microstructure Analysis ◽  
Dual Phase ◽  
Resistance Spot ◽  
Spot Welded

scholarly journals Microstructure and Tensile-Shear Properties of Resistance Spot-Welded Medium Mn Steel

Metals ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 48 ◽  
Author(s):  
Qiang Jia ◽  
Lei Liu ◽  
Wei Guo ◽  
Yun Peng ◽  
Guisheng Zou ◽  
...  
Keyword(s):  
Tensile Shear ◽  
Shear Properties ◽  
Resistance Spot ◽  
Medium Mn Steel ◽  
Mn Steel ◽  
Spot Welded

Enhanced Cross-Tension Property of the Resistance Spot Welded Medium-Mn Steel by In Situ Microstructure Tailoring

2021 ◽  
Vol 21 (2) ◽  
pp. 666-675
Author(s):  
Bingge Zhao ◽  
Yuanfang Wang ◽  
Kai Ding ◽  
Guanzhi Wu ◽  
Tao Wei ◽  
...  
Keyword(s):  
Resistance Spot ◽  
Medium Mn Steel ◽  
Mn Steel ◽  
Cross Tension ◽  
Spot Welded

scholarly journals Influence of the Cooling Time on the Microstructural Evolution and Mechanical Performance of a Double Pulse Resistance Spot Welded Medium-Mn Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 270
Author(s):  
Manfred Stadler ◽  
Ronald Schnitzer ◽  
Martin Gruber ◽  
Katharina Steineder ◽  
Christina Hofer
Keyword(s):  
Fusion Zone ◽  
Heat Generation ◽  
Mechanical Performance ◽  
Electron Backscatter Diffraction ◽  
Cooling Time ◽  
Double Pulse ◽  
Resistance Spot ◽  
Medium Mn Steel ◽  
Mn Steel ◽  
Spot Welded

In the present work, the influence of the cooling time on the mechanical performance, hardness, and microstructural features of a double pulse resistance spot welded medium-Mn steel are investigated. Curves of the electrical resistance throughout the welding revealed that the cooling time strongly influences the heat generation during the second pulse. A second pulse after a short cooling time re-melts the center, and heat treats the edge of the primary fusion zone. This desired in-process heat treatment leads to a modification of the cast-like martensitic structure by recrystallization illustrated by electron backscatter diffraction measurements and to a homogenization of manganese segregations, visualized by energy-dispersive X-ray spectroscopy, which results in an enhanced mechanical performance during the cross tension strength test. In contrast, during excessively long cooling times, the resistance drops to a level where the heat generation due to the second pulse is too low to sufficiently re-heat the edge of the primary FZ. As a consequence, the signs of recrystallization disappear, and the manganese segregations are still present at the edge of the fusion zone, which leads to a deterioration of the mechanical properties.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

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