EXPLOSIVE WELDING OF
ELECTRIC CONNECTORS
V.M. Ogolikhin, S.D. Shemelin
Design and Technology Branch of Lavrentyev Institute of
Hydrodynamics SB RAS, Novosibirsk, Russia
Statement of Problem
There is the problem of energy losses in electric power circuits,
exploited in enterprises of power engineering (electric power stations,
distributive facilities, transforming stations, etc.) and electrometallurgy
(aluminum electrolyzers, remelting equipment, etc.). This problem to a
considerable degree can be solved by reducing of transient resistance
of electric contacts, where current leads made from different materials
are joint together. Normally current leads are made of Cu or Al, and
their joints are subjected to electrochemical corrosion, which causes
the rise of electric resistance.
Decrease of transient resistance can be achieved by use of special
connectors, made with the help of explosive welding.
In this presentation the explosive welding technique, developed for
producing of Al -Cu connectors, is described. Current lead connectors
can be used, when laying the electric power circuits at plants of nonferrous metallurgy and power engineering.
Current lead used in electrometallurgy
usually consists of a great number of
flexible metal (Al or Cu) bands,
assembled into one packet.
The approach consist in explosive
welding of packet end with transition
element (connector) made of the same
or different material.
Further joining of current leads is
provided through these connectors.
1 – packet of bands; 2 – connector;
3 – connector contact surface;
4 – flexible metal bands; 5 – welding zone
between bands; 6 – connector plate; 7 –
welding zone between bands and
connector plate.
Fig. 1 - General view of the flexible current lead
Connection of current leads
Fig. 2 - Flexible Current Lead (cut along)
The left bus consists of 20 copper bands, the right bus – of 20 aluminum bands
Fig. 3 – Explosive welding layout. Top view
1 – packet of bands; 6 – flyer plate; 10 – band open surface; 12 – detonator
Fig. 4 – Section А-А of Fig. 3
4 – flexible metal bands (assembled with regular shift); 6 – flyer plate; 8 – shifted part of
band; 9 – packet slant; 11 – high explosive; Δl – shift step.
Fig. 5 – Symmetric explosive welding layout.
4 – flexible metal bands; 6 – flyer plate; 8 –shifted part of band; 9 – slant line; 10 – band
weld area; 11 – high explosive; 12 – detonator; 13 – symmetry plane.
Fig. 6 – The packet with milled end faces
4 – flexible metal bands; 6 – flyer plate; 9 – band packet slant line;
11 – explosive; 12 – detonator; 13 – symmetry plane;
14 – spacing. Arrows mean that packet is clipped.
Fig. 7– The packet with the weld - preventing interlayers
4 – flexible metal bands; 6 – flyer plate; 9 – slant line; 10 – band weld area; 11 –
explosive; 12 – detonator; 13 – symmetry axis; 15 - weld - preventing material; 16 – margin
areas of bands.
Fig. 8 – Aluminum band packets, welded with copper plates
Number of flexible bands is 74 pcs.
Conclusions
1. The proposed design of the flexible current lead
enables to reduce significantly the electric-current
losses on the internal and external contacts of the
current lead. Current lead connectors can work at
temperature up to 500 ˚С.
2. The proposed explosive welding technique permits
to bond the connector plate with flexible metal
bands, and simultaneously to weld the adjacent
bands each with another over their end areas.