Relationship between Strength and Process Parameters in Friction Stir Spot Welded PVC Joint Fabricated Composite Material at Welded Region
Yohei KURABE, Yukio MIYASHITA and Hisashi HORI
Abstract:Relationship between process parameter, such as tool rotation speed and plunging speed, and strength of FSSWed PVC joint compounded SiC particle in the welded region was investigated. In case of a joint compounded SiC particles, width of welded area increased compared with that of a joint without SiC particles due to increasing heat input during the process by friction between a rotating tool and SiC particles in all welding conditions tested. In case of a joint joined with the medium heat input condition, elastic modulus at the composite region was higher than that at stirred region in a joint without SiC particlse and the similar as that of the base material. On the other hand, in case of a joint joined with higher heat input condition, degradation of mechanical property at the composite region occurred significantly in the joint compounded SiC particles. The maximum tensile shear loads of the joints joined with the lower and medium heat input conditions were improved by fabricating composite material in welded region. However, the maximum tensile shear load obtained in a joint joined with the higher heat input condition was similar or lower than that of a joint without SiC particle. Effect of width of welded area and elastic modulus at the composite region on joining strength was evaluated with J-integral. Strength of the joint was affected by not only width of welded area but also mechanical property of the composite region. Heat input generated by fabricating composite material in the welded region leads to form larger width of welded area and results in higher the maximum tensile shear load. However, in the same time, mechanical property of composite region is also possibly degraded due to excessive heat input. In order to optimize the welding condition, both effect of changes in size and mechanical property of welded area should be taken into account. Key Words:Friction stir spot welding, Polyvinyl chloride, SiC particle, Composite material, J-integral