When should you use diffusion bonding or explosive welding instead of arc welding?

[bill nye scienceguy!]

by cold welding i mean diffusion bonding, explosive welding, cold pressure welding etc.

in what situations would one use these techniques and what are the benefits of employing them over traditional methods such as arc welding?

 

[mgb_phys]

Usually for two metals that can't be welded any other way, in cryogenic applications Copper-Stainless is common.
The term "cold welding" is normally used for two parts of the same metal being joined by being super-clean and pressed together.

 

[PerennialII]

Applications have worked with have involved bonding "quite" differing materials, like highly differing metals (Cu to steel, like needed in a fusion reactor), ceramic to steel (some high temperature blades) and so. For such materials arc welding for one produces crappy joint quality with deficient material properties and that is a reason to search for other, more exotic and expensive, means.

 

[Astronuc]

by cold welding i mean diffusion bonding, explosive welding, cold pressure welding etc.

in what situations would one use these techniques and what are the benefits of employing them over traditional methods such as arc welding?

As the others mentioned, if one has two dissimilar metals with very different properties, one may wish to bind them without dissolving one in the other, which is what happens with fusion welding.

Many applications like diffusion bonding, explosive or cold pressure welding involve large surface areas and one simply wants to clad a structural material with a relatively thin layer of another metal, say for corrosion protection or wear resistance. The colder or rapid process leaving the metals mostly unalloyed except for the diffusion bond layer at the interface.

 

[bill nye scienceguy!]

thanks everyone, very useful info.