GB1173971A - An Improved Joint Assembly - Google Patents

Abstract

1,173,971. Welding by fusion. HYDRO-CARBON RESEARCH Inc. 6 Feb., 1967, No. 5613/67. Heading B3R. [Also in Divisions F2 and G1] A joint assembly for coupling a pipe 10 of a first metal, such as aluminium, to a pipe 12 of a second metal such as stainless steel comprises a first flanged annular member 14 of said first metal adapted to be welded at 22 to said pipe 10, a second flanged annular member 18 of said second member adapted to be welded to said pipe 12, and a composite gasket 32 formed by integrally-united rings 25a and 25b of said first and second metals respectively, each welded around its periphery at 34 and 35 to the respective annular member 14 or 18 of the same metal, said rings being integrally united by casting the metal of one ring on the other to form interface alloy layer therebetween. As shown, the flanged member 14 is provided with a loose collar 16 which is bolted to the other flanged member 18. Alternatively, both flanged elements may be provided with loose collars or both collars may be omitted, Fig. 4 (not shown). In a further embodiment, Fig. 8 (not shown), the flanged members are locked together by a C-shaped clamp. As described, the aluminium ring 25a is cast on to the stainless steel ring 25b which has been pre-heated and dipped in a hot fluoride flux, the resulting assembly being cooled to give the desired aluminium/stainless steel alloy bonding interface layer. As shown, the rings 25a and 25b are provided with annular lands and projections 37, 36, whilst Figs. 2-8 (not shown), illustrate modifications of the ring forms. The composite gasket is preferably formed with a recess 32 around the periphery to give flexible annular flanged portions which are welded to the associated first and second flanged annular members. The members of aluminium may be alternatively of copper or other non-ferrous metal and the stainless steel members may be of austenitic steel or other ferrous metal.