SU1479246A1 - Method of diffusion welding through interlay - Google Patents

Abstract

The invention relates to pressure welding with heating, in particular to the diffusion welding of hard alloy with non-magnetic metals and alloys, and can be used in mechanical engineering and instrument making. The purpose of the invention is to increase strength by creating local eutectic zones. An intermediate gasket is placed between the welded surfaces of the parts to be joined, containing an interlayer of material that forms a eutectic with the material of at least one of the parts to be welded and an interlayer of material that does not form an eutectic with them, in which the holes are preliminarily made. The parts are compressed, heated to the welding temperature, and isothermal aging is carried out. The eutectic melt formed during the isothermal holding process fills the gaps between the surfaces being welded through the holes, increasing the strength of the joint.

Description

The invention relates to pressure welding with heating, in particular to the diffusion welding of hard alloy with non-magnetic materials and alloys, and can be used in mechanical engineering and instrument making.

The purpose of the invention is to increase strength by creating local eutectic zones.

The method is carried out as follows.

The welded surfaces of the parts are carefully ground and degreased with acetone. An intermediate gasket is placed between them, containing a layer of material that forms a eutectic with a material of at least one of the parts to be welded, and a layer of material that does not form

, eutectic with them, in which holes are made. The parts are squeezed, heated to the welding temperature and an isothermal holding is carried out. During the isothermal holding process, a eutectic melt is formed in the joint zone, filling the gap between it and the welded part through the holes in the second interlayer. The inert interlayer, on the one hand, prevents the eutectic melting of the parts themselves; on the other hand, the holes in it create the possibility of local eutectic melting of the material of the parts being welded, the formation of diffusion bridges in the zone of the holes, on which the melting occurs

oh

rivets, which allows to increase the strength of the connection.

Example. Cylindrical parts are welded from TbFe and copper with a diameter of 5 mm and a height of 3-10 mm. The end surfaces of TbFe and copper are mechanically leveled by grinding on emery paper of different grain sizes. Before bringing the surfaces into contact, the copper parts are wiped with acetone, and the surfaces of the TbFe2 parts are ground once more on emery paper to remove the oxide film. Copper foil 0.03 mm thick and molybdenum foil 0.05 mm thick with 0.3 mm holes are placed between the parts of TbFeg and copper. Foil parts are assembled in the sequence of TbFe2 - (Cu - Mo) - Cu in such a way that Tere2 contacts with copper foil. An insignificant load (on the order of 0.01 MPa) is applied to the parts installed in a special holder in order to squeeze out excess melt from the gap between the parts to be welded and fix them.

The parts are placed in a vacuum furnace and annealed in vacuum to mm Hg at a temperature of 930 ° C, which is higher than the eutectic melting temperature of the TbFe2-Cu system (870 ° C), for 35 minutes. Then the parts are cooled with the furnace.

In the process of annealing, the copper foil in contact with TbFe2 forms a eutectic melt that flows through the holes in the molybdenum foil to the surface of the copper part, wetting it and ensuring full physical contact of the parts with the molybdenum gasket. Diffusion exchange between TbFe3 and Cu, as well as local contact melting, continues through the holes.

Upon cooling, the melt solidifies, ensuring the formation of a monolithic joint in the hole zone.

Claims (1)

Invention Formula about The method of diffusion welding through an intermediate gasket containing a layer of material that forms a eutectic with the material of at least one of the parts to be welded, and a layer of material that does not form a eutectic with them, in which parts are squeezed, heated to the welding temperature and isothermally aged wherein, in order to increase strength by creating local eutectic zones, openings are made in the interlayer of material that does not form a eutectic.