#welding  fastening two pieces of metal together by softening with heat and applying pressure
  supertype:  #fastening__attachment  the act of fastening things together
  subtype:  #butt_welding  creating a butt joint by welding
     subtype:  #flash_welding__flashwelding__flash_butt_welding  butt welding by creating an electric arc between the two pieces which melts and joins them; used for joining segments of metal pipe

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