TWI Industrial Member Report Summary 206/1983
By S B Dunkerton
Friction welds have been produced in 25mm diameter carbon manganese steel to BS 2772 150M19, to determine the effect on mechanical properties of a post rotational twist. The twist acts at the end of the friction cycle thereby inducing further deformation in the weld. It is shown that improved tensile and bend properties are achieved with twisted welds when compared to conventional welds within the conditions studied. Impact properties, on the other hand, only show a significant improvement when a very clean steel is examined, i.e. <0.005%S.
The microstructures of twisted welds are finer than those of conventional welds and contain acicular ferrite in preference to other high temperature transformation products. Consequently, twisted welds also have Lower weld hardnesses than similar conventional friction welds.