On the Effect of Faying Face Condition on Weldability in Friction Welding (The 2nd Report)

Abstract

This report deals with the effect of faying face condition on welding phenomena and mechanical properties of the welded joint in continuous drive type friction welding.
The base metals used were pure aluminium and 0.25% carbon steel. Conditions of faying faces are labelled as,
A: Clean face degreased with benzine
B: Greased face
C: Face covered with oxide film
D: Face with a drilled hole of 1 mm in diameter and 3 mm in depth.
Main results are as follows;
(1) There is no problem to make the joint, which has good qualities in tensile test and bending test, in case of A.
(2) In case of B, the weld, which is made by using lower friction and upsetting pressures, is broken in the aluminium zone adjacent to weld interface in tensile test and has small cracking angle in bending test. These phenomena are caused by pores owing to grease itself and steel particles, which are kneaded into the aluminium base metal in width of 0.1 mm from the rubbing interface.
(3) In case of C, the weld has low tensile strength and poor bending ductility, which are attributed to the oxide film remained at the weld interface.
(4) In case of D, the centre hole of faying face does not affect strength and bending ductility of the weld, unless the ratio of area of the hole to that of faying face is not so large.