scholarly journals An Exploratory Study on Resistance Spot Welding of Titanium Alloy Ti-6Al-4V

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2336
Author(s):  
Ichwan Fatmahardi ◽  
Mazli Mustapha ◽  
Azlan Ahmad ◽  
Mohd Nazree Derman ◽  
Turnad Lenggo Ginta ◽  
...  
Keyword(s):  
Fusion Zone ◽  
Heat Input ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
High Heat ◽  
Spot Weld ◽  
Weld Nugget ◽  
Optimum Level ◽  
Resistance Spot ◽  
High Heat Input

Resistance spot welding (RSW) is one of the most effective welding methods for titanium alloys, in particular Ti-6Al-4V. Ti-6Al-4V is one of the most used materials with its good ductility, high strength, weldability, corrosion resistance, and heat resistance. RSW and Ti-6Al-4V materials are often widely used in industrial manufacturing, particularly in automotive and aerospace industries. To understand the phenomenon of resistance spot weld quality, the physical and mechanical properties of Ti-6Al-4V spot weld are essential to be analyzed. In this study, an experiment was conducted using the Taguchi L9 method to find out the optimum level of the weld joint strength. The given optimum level sample was analyzed to study the most significant affecting RSW parameter, the failure mode, the weld nugget microstructure, and hardness values. The high heat input significantly affect the weld nugget temperature to reach and beyond the β-transus temperature. It led to an increase in the weld nugget diameter and the indentation depth. The expulsion appeared in the high heat input and decreased the weld nugget strength. It was caused by the molten material ejection in the fusion zone. The combination of high heat input and rapid air cooling at room temperature generated a martensite microstructure in the fusion zone. It increased the hardness, strength, and brittleness but decreased the ductility.

scholarly journals Effect of Double Pulse Resistance Spot Welding Process on 15B22 Hot Stamped Boron Steel

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1279
Author(s):  
Hwa-Teng Lee ◽  
Yuan-Chih Chang
Keyword(s):  
Heat Input ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Double Pulse ◽  
Weld Nugget ◽  
Boron Steel ◽  
Welding Parameters ◽  
Tensile Shear ◽  
Resistance Spot

Double pulse resistance spot welding process by applying a second step welding current is a new pathway to alter the mechanical properties for advanced high strength steels. Herein, the resistance spot welding (RSW) of hot stamped boron steel 15B22 by one-step and two-step welding with different welding currents is investigated. The results of the tensile–shear test, size of the weld nugget, hardness distribution, microstructure, and failure mode of different welding parameters are analyzed. The weldment of the two-step RSW with a higher heat input exhibits a lower tensile–shear load and lower fracture energy when the size of the weld nugget is large. The microstructural study reveals the appearance of a partially melted zone and sub-critical heat affected zone in the weldment where the fracture readily occurred. Thus, the two-step RSW process weakens the strength of the sample, which is attributed to the partial softening in the weldment due to the higher heat input.

Evolution of Interfacial Microstructure During Resistance Spot Welding of Cu and Al With Ni-P Coating

2021 ◽  
Author(s):  
Nannan Chen ◽  
Hongliang Wang ◽  
Jingjing Li ◽  
Vic Liu ◽  
James Schroth
Keyword(s):  
Heat Input ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Void Formation ◽  
Welding Process ◽  
Kirkendall Effect ◽  
Interfacial Microstructure ◽  
Formation Mechanisms ◽  
Elemental Distribution ◽  
Resistance Spot

Abstract Dissimilar materials of copper (Cu) to aluminum (Al) with nickel-phosphorus (Ni-P) coatings were joined using resistance spot welding. The Ni-P coatings were electroless plated on the Al surfaces to eliminate the formation of brittle Cu-Al intermetallic compounds (IMCs) at the faying interface between Cu and Al. Three welding schedules with various heat input were employed to produce different interfacial microstructure. The evolution of interfaces in terms of phase constitution, elemental distribution and defects (gaps and voids) was characterized and the formation mechanisms were elucidated. During the welding process, the bonding between Cu and Ni-P forms through solid-state diffusion, while the faster diffusion rate of Cu relative to Ni and P atoms promotes the generation of sub-micron voids. As the heat input increases, gaps at the Cu/Ni-P interface diminish accompanied by increase of sub-micron voids. A moderate schedule helps to remove the gaps and inhibits the void formation. An Al3Ni layer and nanovoids were found around the interface of Ni-P/Al. The increased heat input decreases the grain size of Al3Ni at the interface by eutectic remelting and increases the nanovoids by enhanced nanoscale Kirkendall effect.

scholarly journals Optimization on Spot Weld Parameters in Resistance Spot Welding Process on AISI 304

2021 ◽  
Vol 11 (3) ◽  
pp. 181-185
Author(s):  
Amit Hazari ◽  
Rith Saha ◽  
Bidisha Ghosh ◽  
Debraj Sengupta ◽  
Sayan Sarkar ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Electrical Current ◽  
Industrial Applications ◽  
Spot Weld ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Weld Time

The spot welding procedure is used in a variety of industrial applications. The most critical elements influencing welding quality, productivity, and cost are the spot welding parameters. This research examines the effect of welding factors such as welding current and welding time on the strength of various welding joint designs. Resistance spot welding (RSW) is used in the automotive industry for manufacturing. This research focused on the optimization of process parameters for resistance spot welding (RSW), as well as the tensile testing and spot weld diameter. The goals of this analysis are to comprehend the physics of the process and to demonstrate the effect of electrical current, weld time, and material type on the resistance spot welding process.

EVOLUTION OF INTERFACIAL MICROSTRUCTURE DURING RESISTANCE SPOT WELDING OF CU AND AL WITH AND NI-P COATING

2021 ◽  
pp. 1-12
Author(s):  
Nannan Chen ◽  
Hongliang Wang ◽  
Jingjing Li ◽  
Vic Liu ◽  
James Schroth
Keyword(s):  
Heat Input ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Dissimilar Materials ◽  
Kirkendall Effect ◽  
Interfacial Microstructure ◽  
Formation Mechanisms ◽  
Elemental Distribution ◽  
Resistance Spot ◽  
State Diffusion

Abstract Dissimilar materials of copper (Cu) to aluminum (Al) with nickel-phosphorus (Ni-P) coatings were joined using resistance spot welding. The Ni-P coatings were electroless plated on the Al surfaces to eliminate the formation of brittle Cu-Al intermetallic compounds (IMCs) at the faying interface of Cu to Al. Three welding schedules with various heat input were employed to produce different interfacial microstructure. The evolution of interfaces in terms of phase constitution, elemental distribution and defects (gaps and voids) was characterized and the formation mechanisms were elucidated. During the welding, the bonding between Cu and Ni-P form through solid-state diffusion, while the faster diffusion rate of Cu relative to Ni and P atoms promotes the generation of sub-micro voids. As the heat input increases, gaps at the Cu/Ni-P interface diminishes accompanied by increase of sub-micro voids. A moderate schedule helps to remove the gaps and inhibit the voids formation. An Al3Ni layer and nanovoids were found around the interface of Ni-P/Al. The increased heat input decreases the grain size of Al3Ni at the interface by eutectic remelting and increases the nanovoids by enhanced nanoscale Kirkendall effect.

Simulating Thermoelectric Effect and Its Impact on Asymmetric Weld Nugget Growth in Aluminum Resistance Spot Welding

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Lin Deng ◽  
YongBing Li ◽  
Wayne Cai ◽  
Amberlee S. Haselhuhn ◽  
Blair E. Carlson
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Weld Nugget ◽  
Thermoelectric Effects ◽  
Element Analysis ◽  
Resistance Spot ◽  
Seebeck Coefficients ◽  
Nugget Growth ◽  
Simulation Results ◽  
The Impact

Abstract Resistance spot welding (RSW) of aluminum–aluminum (Al–Al) is known to be very challenging, with the asymmetric growth of the weld nugget often observed. In this article, a semicoupled electrical–thermal–mechanical finite element analysis (FEA) procedure was established to simulate the RSW of two layers of AA6022-T4 sheets using a specially designed Multi-Ring Domed (MRD) electrodes. Critical to the modeling procedure was the thermoelectric (including the Peltier, Thomson, and Seebeck effects) analyses to simulate the asymmetric nugget growth in the welding stage. Key input parameters such as the Seebeck coefficients and high-temperature flow stress curves were measured. Simulation results, experimentally validated, indicated that the newly developed procedure could successfully predict the asymmetric weld nugget growth. Simulation results also showed the Seebeck effect in the holding stage. The simulations represent the first quantitative investigation of the impact of the thermoelectric effects on resistance spot welding.

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