The electrical welding device adds {HEAD ~ material} to {TAIL ~ the inside} of the valve body by using an electrode to provide an arc 
to
The electrical welding device adds { HEAD ~ material } to { TAIL ~ the inside } of the valve body by using an electrode to provide an arc
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH