1 11 SOME APPLICATIONS OF EXPLOSIVE METALWORKING FOR ALUMINUM INDUSTRY A.Z.Bogunov, A.A.Kuzovnikov JSC « Pulse technologies » , Krasnoyarsk, Russia, POB 26780,

2 JSC «Pulse technologies» Fabrication of the steel-aluminum transition inserts for anode holder of aluminum electrolyzer. Developed technology of explosive welding with dovetail type bond of connection. About steel-aluminum inserts were manufactured and delivered for aluminum industry.

3 Objectives for explosive metalworking Decrease of voltage drop Treatment of cathode bar for recycling Cooling of Shell Detachable Contact joint Connection of bus bar Bimetallic inserts

4 Removal the cast-iron coating from cathode bar 1 Сathode bar casting by melting cast iron at blocks Used cathode bar with cast iron coating Сathode bar with coating White cast iron, thickness mm Cast iron, thickness mm Welding at the casting place Cast-iron Steel

5 Removing cast iron coating from cathode bar for recycling 2 Recycling cathode bar 1.Chipping cast iron at the side and at the bottom, HE charge 1,6 kg/m 2.Partial removal from casting side, HE charge 1 kg/m 3.Milling welding patch Packaged ammonite6 Base cathode bar High economic efficiency There are problems with nonflat geometry of used cathode bar

6 Iron cathode- descent detachable connections 1 – copper aluminum contact; 2 – contact copper layer; 3 – flexible multilayer descent; 4 – cathode bus bar; 5 – cathode bar; 6 – hardware. Contact 1 Copper 5mm, aluminum 50mm Contact 2 Copper 2mm, aluminum 40mm

7 Anode descents for electrolizer with side current leads Option1: Aluminum with thickness 30 – 40 mm was welded at the end of copper strip with thickness 10 mm Option2: Aluminum with thickness 10 – 20 mm was welded overlapping at the 1/3 copper strip with thickness 10 mm Connection Cu – Al is made by explosive welding instead of fusion welding: High reliability of connection Substantial reduction of copper consumption

8 Split connection anode rod – anode bus bar Contact copper-aluminum plates are mounted on anode bus bar, copper 2mm Copper coating at the side surface of the anode rod, copper 2mm Contact Al – Al was changed by contact Cu - Cu

9 Bimetal contacts with riffled surface 1 Different types of copper surface asperities on aluminum base, size 2 mm Titanium surface asperities on the aluminum base, size 0,35mm Surface asperities are made from more hard material than base Asperities are penetrated into the opposite surface and cut through the oxide films Eliminating of the state of the contact surface (non-flatness, roughness, contamination) influence

10 Bimetal contacts with riffled surface 2 Processing concept of contact with riffled surface Voltage drop-contact pressure dependence 30x30mm, current 100А Flat surface Riffled surface, asperities 2 mm SS-Al Ni-Al Р, KPa U, mV U decrease in 20 – 50 times for pure contact and in times for contamination contact U has inverse proportionality asperities size At the small loading U for pyramid type asperities in 2 times smaller than for stripe asperities

11 Bimetal cooling ribs of pot shell Working temperature С Life time – more than 5 years Option 1: Explosive welding fabricated rib Stimulation of electrolysis process of aluminum production (pat.RF ) Option 2: Transition pieces Al 10 mm – Ti 0,5mm – steel 20mm, dovetail connection Steel-aluminum cooling ribs

12 Bridge connections aluminum bus bar 1 The works must de done at the shop conditions Minimal HE charge Explosive localizer is a part of charge construction. Cutoffs of detonation cord 10 g/m, diam.5 mm Explosive welding on a base of detonation cord Tensile strength МРа, waveless bond HE consumption : Al 5mm (2 plate) – 0,05 g/сm 2 Al 15mm – 0,1 g/сm 2 Stationary detonation D 3,5 кm/s

13 Aluminum thickness mm Inclination angle, grade TampingResult 50yeswelding 60no/yesNo/ welding 100no/yesNo 105yeswelding 107,5yeswelding 10 yeswelding 1511yeswelding Bridge connections aluminum bus bar 2 Bridge bus bar butt connection, 2 bridges with thickness 15 mm Overlapping connection bus bar, 2 bridges with thickness 15 mm L – likes connection, thickness of bridge 10 mm

14 Butt connection thick aluminum bus bar Works must be done at the shop conditions Minimal HE charge Bus bar thickness– 80 mm Not overlapping connection Standoff Busbar Insert with bore filled by HE Wave bond (Ammonite 6) D HE consumption : Detonation cord - 0,25 g/сm 2 Ammonite 6 – (0,1-0,13) g/сm 2 Average tensile strength 40 MРа Bore (5,5 – 6) mm Standoff (0,5 - 1) mm Welding region

15 Conclusion 1.Used cathode bars mounted in a block by pouring cast iron may be cleaned by the explosion for recycling. 2.Bimetallic contacts with the riffled surface can provide a significant reduction in the voltage drop in high-current connections. 3.Different versions of bimetallic cooling ribs of pot shell were developed for intensification of aluminum electrolysis. 4.Explosive charges on the basis of detonation cord provide welding of thick aluminum up to 15 mm for the bridge connection of aluminum bus bar. 5.The technology for the butt connections of thick aluminum bus bar was developed.

16 Thank for your attention