Evaluation of Usefulness of AlCrN Coatings for Increased Life of Tools Used in Friction Stir Welding (FSW) of Sheet Aluminum Alloy.

Grzegorz Luty,Paweł Wieczorek,Wojciech Więckowski,Maciej Motyka,Piotr Lacki

doi:10.3390/ma13184124

Abstract

The study presents the results of examinations of wear in tools made of 1.2344 steel without and with an anti-wear coating in the process of welding overlap joints of sheet metal made of 7075-T6 aluminum alloy using friction stir welding (FSW) technology. A commercial anti-wear AlCrN coating (Balinit® Alcrona Pro by Oerlikon Balzers Coating Poland Sp. z o.o., Polkowice, Poland) was examined, applied using physical vapor deposition (PVD) and used to improve tool life in metalworking processes. Wear tests for the tools were conducted in industrial conditions at specific parameters of the friction stir welding process. Tool wear was evaluated through examination of the tool working surface. The results of the static tensile strength tests and metallographic examinations of the joints were used to evaluate the effect of tool wear and the coating impact on joint quality. The results obtained in the study show that the tool made of 1.2344 steel was intensively worn after the welding of a joint with the length of 200 m, increasing the risk associated with further use of the tool and suggesting the tool’s low durability. The use of the AlCrN coating led to an increase in tool life. The coating limits the process of tool wear and can be used as an anti-wear coating for tools used in the FSW of aluminum alloys.

Highlights

Friction stir welding (FSW) technology allows for welding joints with good mechanical and structural properties, and it has been widely used in many industries, e.g., automotive, defense, energy, aerospace, rail and machine building sectors [1,2,3]
The present study aimed to evaluate the usefulness of an anti-wear coating in terms of the application and the improvement of tool life during the friction stir welding (FSW) of 7075-T6 aluminum alloy sheet metals
The study demonstrates the quality of and joints affected of byaboth the degree of (changing tool wear theispresence protective coating and the presence of a protective coating, responsible for the transport of the plasticized material and the amount of heat friction conditions), responsible for the transport of the plasticized material and the amount of heat generated in the weld

Summary

Introduction

Friction stir welding (FSW) technology allows for welding joints with good mechanical and structural properties, and it has been widely used in many industries, e.g., automotive, defense, energy, aerospace, rail and machine building sectors [1,2,3]. A significant problem hindering the joining of materials in FSW is the low durability of the tools [4]. The intensity of tool wear depends on the type of tool material in combination with the welded material, tool design and welding parameters [3,5,6]. Tool wear leads to modification of the geometry of the working part of the tool, which, along with properly chosen process parameters, is responsible for joint quality [7,8,9,10]. The reasons for defect formation in FSW joints have already been discussed [11], as has the possibility of defect detection using ultrasonic testing [12]

Methods

Results

Conclusion