Don't know about MIG welding them but you can silver solder or braze them.
I just run the ends of the blade on the bench grinder to create a scarf and then silver solder the joint. A quick touch with a file afterwards and they're good to go.
Have to say I'm only a hobby user so not sure how this would stand up to commercial use but it works for me.
HTH
Jim
if there done right they go the distance ok. silver soldered or brazed


