Experimental investigation of pin geometry influence on impact strength of friction stir welds in polypropylene composites

F. Kordestani^*, N. B. Mostafa Arab, F. Ashenai Ghasemi, R. Eslami Farsani

The 1^st International and 6^th Joint Conference of Iranian Metallurgical Engineering Society and Iranian Foundry Men’s Society, Tehran, Iran, Nov. 6-8, 2012. 

Abstract

Friction stir welding (FSW) is a solid-state welding process which has been successfully applied in several industries such as aerospace and automotive for joining materials. The friction stir tool is the key element in FSW process. In this study, the influence of four different tool pin geometries on impactstrength of two types of polypropylene composite plates with 30% glass fiber (GF) and 30% carbon fiber (CF) have been investigated. For this purpose four different stir pins namely threaded taper pin, squarepin, four flute threaded pin and threaded taper pin with chamfer were made and used to carry out buttwelding of 5 mm thick plates. Standard Izod impact test was performed to evaluate the impact toughnessof the welded specimens. The results indicated that threaded taper pin with chamfer produced welds with better surface appearance and higher impact strength. The impact tests showed that the total impactenergies increased in the FSW composites, respect to the corresponding base materials. It was also found that with this tool, the impact strength of the specimens for GF composite and CF composite were about40% and 50% that of the base materials respectively.

 Keywords

Carbon fiber; Friction stir welding; Glass fiber; Impact strength; Pin geometry; Polypropylene.

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