Diffusion welding of bearing bushes in steel parts - using difference in thermal expansion to generate pressure during heating

摘要

In a process for joining a hollow bush, made of non-ferrous metal, to the bore of an iron or steel part, the bush is inserted and a high-strength supporting core is then inserted in the bush, the core material having a higher m.pt. than the material of the bush and preventing the bush from shrinking. The assembly is then heated for diffusion welding of the parts. A low m.pt. metal may be placed between the parts opt. with another metal forming an alloy with the low m.pt. metal, the alloy having the same or similar structure as =1 of the parts being joined, and a groove may be provided for the additional metal(s); heating for welding may be in a moderate vacuum or in inert gas. Used e.g. for diffusion welding of a bearing bush in a steel housing or cylinder-drum for axial- or radial-piston engines. A flaw-less metallurgical bond is obtd. and no special device is required for applying press., which is generated by the difference in thermal expansion of parts being welded.