combinations of operations covered by any particular subclass of class Fulltext... Hierarchy... Expanded...B21 with operations covered by other classes, e.g. with operations involving removal of material, which are also covered by subclass Fulltext... Hierarchy... Expanded...B23P, except that if the operations covered by the other classes are subsidiary to the operations properly covered by a single subclass of Fulltext... Hierarchy... Expanded...B21 the combination is classified in that subclass.
Processes of a kind covered by this class but applied to non-metallic materials are classified in this class if they are applicable to metal and cannot be classified fully in another class.