Friction Welding of Malleable Cast Iron and Carbon Steel

Abstract

The possibility of friction welding of malleable cast iron and S48C carbon steel of 12 mm diameter was investigated. And experiments on some fundamental welding phenomena to be related with the tensile property of the joint were carried out.
The welding machine used was of continuous drive type, and the experimental range of the weld-ing factors was,
rotational speed: 3600 rpm,
heating pressure: 4.0-9.0 kg/mm²,
upsetting pressure: 9.0 kg/mm²,
heating time: 20-80 sec.
Main results of the study are as follows;
(1) When heating pressure Ph of 6.0, 7.0 and 8.0 kg/mm² and the comparatively long heating time are selected, the joint having the tensile strength equivalent to that of base metal can be got. The specimen obtained under the condition of heating pressure 7.0 kg/mm² and heating time 40 sec trends to be broken at base metal in tensile test.
(2) To get such sound joint that fracture takes place at base metal in tensile test, it is required that the graphite adjacent to friction interface in cast iron is diffused in its surrounding ferrite and the region enriched with carbon by diffusion is molten so far as the graphite disappears. Moreover, the requirement that graphite in the area continued to the above-mentioned area should not be flattened severely is added.
(3) In the joint broken at the weld, the graphite adjacent to the interface remains in severely flattened state or finely torn.