Exotic welding

It must have been the weather, but was watching a bit of TV the other day and saw two interesting welding techniques - both of which I doubt any of us will use.

The first was on the Yesterday Channel, showing the use of friction welding to joins sections of the Orion manned module together. Basically the two sections were brought together and a fast rotating metal tool was pressed against the joint to produce the heat. The nearest we get to it is when we snap a drill off in a deep hole !

The second was on the BBC Repair Shop, where a broken small gold brooch was joined back together using a laser beam.

Friction welding is also used to fuse together big pieces of steel.

One of the projects which I worked on was machinery that replaced the anodes used in aluminium smelters. Aluminium is made in enormous electrical furnaces and use carbon anodes. ( Aluminium smelter use more electricity than that of a small town). The anodes are basically big blocks of carbon 900 x 900 x 1000 - 1500mm long and mounted on a steel stem. The stem has a number of branches at the bottom which fit into holes in the carbon block. Molten cast iron is used as a filler for bonding them together (similar process to solderring but on a bigger scale).

The carbon is eventually eroded away and has to be replaced. The bottom of the support stems is cut off and new ones welded in place. The re-furbished stem is used again with a new carbon block.

New pieces are spun at speed and friction welded to the bottom of the spigots at the bottom of the support stem. These are 150 - 250mm diameter and welded in minutes.

Paul

Photo after the pouring of cast iron.

I use a PUK welder for micro-welding jewellery. Its made by a German company called Lampert. The name is an onomatopoeia for the sound it makes when welding. **HERE** is a short video of one in action.

When at work part of the repair of mould tools used to be done by inserting apiece of steel without showing any Mark or scar on the finnished part but for the last few years we had the damage welded by laser welding and it made repairs so easy in comparison. The laser welder was a mobile unit and so in many cases we didn't have to to evan have to strip or dismantle the tool.

David

Many drill bits have the HSS business end friction welded to the carbon steel (aka silver steel aka drill rod) shank by friction welding.

It is informative to play around in the lathe with two pieces of mild steel bar, one held in the chuck and spun and the other held fast in the tailstock chuck. Bring them together hard enough for long enough and the rubbing ends will glow red and if power is cut to the motor, they will weld together. Maybe not the best thing for the motor and drive but certainly has been known to keep apprentices amused for some time.

On a slightly different scale, one of the top welders where I used to work, cut a coke can open and made a flat sheet, then cut that in half, so he ended up with two pieces of al. alloy sheet about 150mm x 60mm x 0.2mm thick. He then welded to two sheets back together to form one piece about 150mm x 120mm x 0.2mm thick.

Well I was impressed!!

cheers

Bill

Back in the early '70s I went round Dagenham and saw valve heads being friction welded to stems in the factory. Yes they actually made car parts in the factory back then.

The most exotic welding I've seen was the neutron beam welder in the Welding Institute in '76. It was the year of the ladybird explosion and their rural tree lined paths were carpeted in the bugs making walking between buildings a disturbingly crunchy experience.