Strengthening Mechanism of TiB2-TiC Complex Phases Coated Electrode

2012 ◽  
Vol 433-440 ◽  
pp. 251-255 ◽  
Author(s):  
Ping Luo ◽  
Shi Jie Dong ◽  
Zhang Qiang Mei ◽  
Zhi Xiong Xie
Keyword(s):  
Failure Mechanism ◽  
Current Density ◽  
Spot Welding ◽  
Single Phase ◽  
Welding Process ◽  
Strengthening Mechanism ◽  
Galvanized Steel ◽  
Steel Weld ◽  
Galvanized Steels ◽  
Coated Electrode

TiB2-TiC complex phases coating deposited onto the surface of electrodes by electro-spark deposition (ESD) in order to prolong the life of single phase coated electrode (TiB2 or TiC) during resistance welding of galvanized steels. The microstructures and TiB2-TiC complex phases coatings were characterized by SEM and XRD. The results indicate that life of TiB2-TiC complex phases coated electrode is prolonged significantly than life of single-phase coated electrode （TiB2 or TiC ）, failure mechanism of TiB2-TiC complex phases coated electrode is mainly wear to cause diameter increase on electrode tip, which results in lower current density during welding process, and then nugget size cannot satisfy the requirement of resistance spot welding. The failure mechanism of TiB2-TiC complex phases coated electrode is obviously different from uncoated electrode, the failure mechanism of uncoated electrode is wear and alloying between electrode tip surface and molten Zn on galvanized steel weld surface.

Modeling of Resistance Spot Welding Process Using Nonlinear Regression Analysis and Neural Network Approach on Galvanized Steel Sheet

2011 ◽  
Vol 291-294 ◽  
pp. 823-828
Author(s):  
Yi Luo ◽  
Chun Tian Li ◽  
Hui Bin Xu
Keyword(s):  
Spot Welding ◽  
Steel Sheet ◽  
Back Propagation ◽  
Welding Process ◽  
Galvanized Steel ◽  
Welding Quality ◽  
Back Propagation Algorithm ◽  
Neural Network Approach ◽  
Newton Raphson ◽  
Current Duration

Modeling of resistance spot welding process on galvanized steel sheet was investigated. Mathematical models developed by nonlinear multiple regression analysis and artificial neural network approach were employed in the prediction of welding quality factors, namely nugget diameter, penetration rate and tensile shear strength, under some welding conditions. According to the prediction models on quality, the prediction systems of welding process parameters were formulated respectively on the basis of Newton-Raphson iterative algorithm and cascade forward back propagation algorithm in order to obtain the desired welding quality. The results showed that the prediction precision of cascade forward back propagation algorithm was higher than Newton-Raphson iterative algorithm. The current duration had the largest prediction error, followed by electrode force and welding current. Therefore, it was concluded that the current duration was the most difficult parameter in prediction system of welding process in order to obtain the desired welding quality.

Effect of Spot Welding Current and Cycles on the Mechanical Properties of Welded Galvanized Steel Sheets

2013 ◽  
Vol 795 ◽  
pp. 87-90 ◽  
Author(s):  
Shamsul Baharin Jamaludin ◽  
Mohd Noor Mazlee ◽  
Muhammad Rifki Ismail ◽  
Khairel Rafezi Ahmad ◽  
Kamarudin Hussin
Keyword(s):  
Mechanical Properties ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Galvanized Steel ◽  
Shear Load ◽  
Tensile Shear ◽  
Steel Sheets ◽  
Welding Cycle

Studies on the effects of welding current and cycles were carried on the galvanized steel sheets using spot welding. The welding currents used were 3 kA, 5 kA 6 kA and the welding cycles were 4, 6 and 8. Tensile shear and tensile peel load were determined on the joint of welded specimens. The results showed that the value of tensile shear load was lower than tensile peel load. The strength of the joint increased with the increasing of welding current and welding cycle used in the welding process.

scholarly journals Microstructure Evolution and Strengthening Mechanism of Galvanized Steel/Mg Alloy Joint Obtained by Ultrasonic Vibration-Assisted Welding Process

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1674
Author(s):  
Fangzhou Yang ◽  
Bing Liu
Keyword(s):  
Ultrasonic Vibration ◽  
Acoustic Streaming ◽  
Welding Process ◽  
Strengthening Mechanism ◽  
Fusion Welding ◽  
Galvanized Steel ◽  
Mg Alloy ◽  
Ultrasonic Power ◽  
Average Grain Size ◽  
Joining Strength

A novel ultrasonic vibration-assisted welding (UVAW) process was used to achieve reliable joining of galvanized steel and Mg alloy. The effects of the UVAW technique on the microstructure and mechanical properties of galvanized steel/Mg alloy weldment were studied in detail. The introduction of ultrasonic vibration can ameliorate the wetting of welds and eliminate porosity defects. A refined microstructure of the fusion welding zone with an average grain size of 39 ± 1.7 µm was obtained and attributed to cavitation and acoustic streaming caused by the UVAW process. The grain refinement led to an increase in the microhardness and joining strength of the galvanized steel/Mg alloy weldment. Under the ultrasonic power of 0.9 kW and a current of 65 A, the maximum joining strength of the ultrasound-treated galvanized steel/Mg alloy joint was 251 ± 4.1 MPa, which was a 14.6% increase over the joint without ultrasonic treatment.

scholarly journals Analysis of tensile-shear strength of single and multi-friction stir spot welding joints under fixed welding process conditions

2020 ◽  
Vol 234 (24) ◽  
pp. 4893-4904
Author(s):  
Morteza Asadollahi ◽  
Neda Jabbari ◽  
Soheil Nakhodchi ◽  
Hossein Salimi ◽  
Hamed Haddad Khodaparast
Keyword(s):  
Shear Strength ◽  
Failure Mechanism ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Friction Stir ◽  
Welding Joints ◽  
Spot Welded

The tensile-shear strength of AA 5052 single and multi-friction stir spot welding joints were analyzed using experimental, numerical, and analytical approaches. Benchmark specimens were designed and manufactured in a similar manner with respect to industrial practice. Under the fixed welding process condition, the failure mechanism of friction stir spot welded specimens under tensile-shear loading was first determined by using macro- and micro-structural analysis. It is shown that increasing the tool shoulder diameter and the number of friction stir spot weldings may nonproportionally increase the strength of the joints. In the linearly arranged multi-friction stir spot welding joints, the strength of these joints was discussed using analytical approach. It is demonstrated that in certain cases, increasing the nugget diameter is preferred than increasing the number of nuggets. This is only applicable to a certain friction stir spot welding failure mechanism. A finite element model prediction tool was developed to predict the tensile-shear strength of friction stir spot welded joints using the material properties obtained from the measurement of experimental hardness.

Resistance Spot Welding Process of Galvanized Steel Sheet Based on Regression Modeling

2009 ◽  
Vol 610-613 ◽  
pp. 681-686
Author(s):  
Yi Luo ◽  
Hong Ye ◽  
Cheng Zhi Xiong ◽  
Lin Liu ◽  
Xu Wei Lv
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Steel Sheet ◽  
Welding Process ◽  
Welding Current ◽  
The Body ◽  
Galvanized Steel ◽  
Spot Welds ◽  
Current Electrode ◽  
Resistance Spot

The resistance spot welding process of galvanized steel sheet used in the body manufacturing of family car was studied, and the indexes of nugget geometry and tensile-shear strength of spot welds were tested. Four process parameters, namely welding current, electrode force, welding current duration and preheat current, and interactions among them were regarded as factors impacting indexes. Method using in mathematical models developing was nonlinear multiple orthogonal regression assembling design, which was optimized by the technology of variance analysis. The experimental results showed that more accurate prediction on nugget size and mechanical properties of spot welds can be obtained by the models optimized. With these prediction results, the optimization of welding process also was realized by the analysis to effect of the parameters and interactions on the welding quality.

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