DURING the first world war it was observed that when armour plating was hit by shrapnel some of the bits not only embedded themselves into the metal but ended up welded to it, a process that normally takes a great deal of heat. Laboratory tests later showed that if one material is accelerated fast enough into another they become plastic at the point of contact and fuse together, even at room temperature. This led to a process called explosive welding which, as its name suggests, uses chemical explosives spread over the top of a sheet of one material to blast it into a sheet below.
Explosive welding, for obvious reasons, is usually carried out in tunnels under mountains or in remote deserts. It is often employed to cover steel plate with a more expensive anti-corrosion layer of stainless steel or nickel alloy. This clad plate is typically used in chemical plants. Now the same idea, minus the explosives, is beginning to be used inside factories to make products ranging from white goods to aircraft and cars.
The process, known as magnetic-pulse welding, works a bit like the Large Hadron Collider near Geneva, accelerating materials into each other...Continue reading
Source: Science and technology http://ift.tt/245Ppag
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