繰返しねじりをうける摩擦圧接継手のひずみ分布と疲労き裂

抄録

The strain distribution and the strain concentration factor of friction welded specimens were examined by applying the copper-electroplating technique. The fatigue cracks, the fatigue limit and the mechanical properties of specimens were also investigated.
The results obtained are summarized as follows:
(1) The change of the strain distribution at the friction welded specimens subjected to repeated torsion, depends on the condition of welding. The strain becomes maximum at the weld interface. The strain decreases with increasing distance from the interface, and become minimum in the heat affected zone. The strain, however, slightly increases again in the parent material sufficiently distant from the interface.
(2) The strain concentration factor decreases in the order of the weld interface, the parent material, and the heat affected zone.
(3) The fatigue crack propagates most rapidly in the parent material, and the fracture of the specimens occurs there.
(4) The hardness (H_V: 200gr) at the surface of the friction welded specimen becomes maximum in the weld interface, and decreases with increasing distance from the interface.