GB1125809A - A method of welding metal pieces by hammering - Google Patents

Abstract

1,125,809. Welding by pressure. EUROPEAN ATOMIC ENERGY COMMUNITY and CENTRO INFORMAZIONI STUDI ESPERIENZE S.P.L. 18 Oct., 1965 [20 Oct., 1964; 30 June, 1965], No. 44080/65. Heading B3R. In welding together metal members of different metals the members are hammered together at a high temperature and in a vacuum or inert atmosphere and as a preliminary step at least one of the members is degasified by heating under vacuum to a temperature at least as high as that employed during hammering. A tube 2, Fig. 1, of zirconium alloy is provided with a belled end and an 18-8 stainless steel tube 1 is engaged therein with an 18-8 stainless steel sleeve 3 over the end of the tube 1 and the overlapped portions of the tubes. The stainless steel members have both been degasified by heating in vacuo. The surfaces to be joined which have been smoothed with emery cloth are heated by a surrounding electric induction coil to about 900‹ C. and are hammered by a rotary hammer in a protective atmosphere. The walls are reduced in thickness and the sleeve is incorporated in the joint which after cooling is cold hammered and then heated at 650‹ C. for 1 hour. In another embodiment the ends of the tubes 11, 12 of stainless steel and zirconium alloy, Fig. 4, are arranged one inside the other without belling inside an annular casing 13 of stainless steel connected to a source of vacuum or inert gas. A mandrel 15 is provided in the centre of the casing. The casing and stainless steel tube have previously been degasified by heating to 1000‹ C. in a vacuum. The tubes are welded in the manner above described and the casing may be removed or left in position. Titanium and steel, zirconium alloy and titanium or aluminium and steel may be welded and the hammering may be manual, or by a mechanical or pneumatic hammer. One of the pieces to be welded may be of a magnesium alloy or of sintered aluminium and the pieces may be sheets.