| 148 / | HD | METAL TREATMENT |
| 95 | DF | PROCESS OF MODIFYING OR MAINTAINING INTERNAL PHYSICAL STRUCTURE (I.E., MICROSTRUCTURE) OR CHEMICAL PROPERTIES OF METAL, PROCESS OF REACTIVE COATING OF METAL AND PROCESS OF CHEMICAL-HEAT REMOVING (E.G., FLAME-CUTTING, ETC.) OR BURNING OF METAL {17} |
| 516 | DF | .~ Producing or treating layered, bonded, welded, or mechanically engaged article or stock as a final product {9} |
| 519 | | .~.~ Pipe or tube {2} |
| 520 | DF | .~.~.~> With induction heating |
| 521 | DF | .~.~.~> With metal fusion bonding |