Effect of Pin Shape on Thermal History of Aluminum-Steel Friction Stir Welded Joint: Computational Fluid Dynamic Modeling and Validation.

Dmitry Olegovich Bokov,Hamed Aghajani Derazkola,Mahmoud E Abdullah,Wanich Suksatan,Aleksandra Świerczyńska,Dariusz Fydrych,Mohammed Abed Jawad

doi:10.3390/ma14247883

Abstract

This article studied the effects of pin angle on heat generation and temperature distribution during friction stir welding (FSW) of AA1100 aluminum alloy and St-14 low carbon steel. A validated computational fluid dynamics (CFD) model was implemented to simulate the FSW process. Scanning electron microscopy (SEM) was employed in order to investigate internal materials’ flow. Simulation results revealed that the mechanical work on the joint line increased with the pin angle and larger stir zone forms. The simulation results show that in the angled pin tool, more than 26% of the total heat is produced by the pin. Meanwhile, in other cases, the total heat produced by the pin was near 15% of the total generated heat. The thermo-mechanical cycle in the steel zone increased, and consequently, mechanical interlock between base metals increased. The simulation output demonstrated that the frictional heat generation with a tool without a pin angle is higher than an angled pin. The calculation result also shows that the maximum heat was generated on the steel side.

Highlights

The friction stir welding (FSW) process belongs to the group of solid-state joining processes—it enables to provide the appropriate amount of welding activation energy in the form of heat without exceeding the melting point of base materials [1]
This paper aims to study the effects of FSW tool pin angle during FSW of AA1100 aluminum alloy and St-14 steel
The results indicate that the St-14 steel stretched into the aluminum side and AA1100 alloy alloy and diffused into the steel side from the middle of the joint—this stir zone shape formed and diffused into the steel side from the middle of the joint—this stir zone shape formed bothsamples

Summary

Introduction

The friction stir welding (FSW) process belongs to the group of solid-state joining processes—it enables to provide the appropriate amount of welding activation energy in the form of heat without exceeding the melting point of base materials (unlike fusion processes: arc, plasma, laser and electron beam welding) [1]. This is advantageous because it limits structural transformations and joint properties changes resulting from the crystallization process [2,3]. The development of FSW follows the directions of research of various variants of the process limiting individual constraints and developing each of the necessary process conditions: welding machine, tool, the workpiece, process flow, etc. [6,7,8]

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