Lines with other classes and within this classCHEMICAL COMPOUND AND COMPOSITION CLASSES (NONMETALLURGICAL). In general, a composition called an alloy and containing metal is prima facie proper for this class (420) unless other disclosure positively reveals it to be properly classified elsewhere. A disclosure that nonmetallic particles are bonded by metal will be taken to denote a continuous phase of metal proper for Class 420 absent specific disclosure to the contrary. Cases of doubt as to whether a continuous phase of metal exists will be resolved in favor of placement in Class 420. A so called alloy which contains no metal is excluded from Class 420 and classified as a composition based upon its use or function. See References to Other Classes, below for classes speficially related to Nonmetallurgical Chemical Compound and Composition Classes. The rules for determining Class placement of the Original Reference (OR) for claimed chemical compositions are set forth in the Class Definition of Class 252 in the section LINES WITH OTHER CLASSES AND WITHIN THIS CLASS, subsection COMPOSITION CLASS SUPERIORITY, which includes a hierarchical ORDER OF SUPERIORITY FOR COMPOSITION CLASSES. METALLURGICAL AND METALLIC STOCK CLASSES Class 420 provides for alloys, or metallic compositions which are intended to be of generally uniform character thought. While perfect uniformity is very difficult to achieve, this class (420) will take products which are not completely uniform where the intent is to produce a practically uniform product and any nonuniformity is accidental, or incidental and is not desired, or intended to give the product advantageous properties. Where a nonuniform product is desired, or intended, e.g., differing composition, or properties in different portions, etc., the product is considered to be stock and classified as appropriate in Classes 148, or 428 as discussed below. This order of superiority among various metal, alloy, and metal stock areas and methods of manufacture involving them is as follows. 1. Class 419, Powder Metallurgy Processes. 2. Class 148, Metal Treatment, subclasses 22+, compositions for treatment of solid metal. 3. Class 75, Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures, subclasses 300, 301, and 303+, gaseous, liquid, or solid treating compositions for liquid metal or charges, and subclass 302, welding rod defined by composition. 4. Class 75, subclasses 228+, consolidated metal powder compositions and subclasses 255+, loose metal particulate mixtures. 5. Class 420, Alloys or Metallic Compositions, claimed as products. 6. Class 148, subclasses 95-122, 194-287, and 500-714, in the schedule order, providing for certain processes of treating solid or semi-solid metal by modifying or maintaining the internal physical structure (i.e., microstructure) or chemical properties of metal, processes of reactive coating of metal or processes of chemical-heat removing (e.g., flame-cutting, etc.) or burning of metal. However, if metal casting, fusion bonding, machining, or working is involved, there is a requirement of significant heat treatment as described in the Class 148 definition. 7. Class 148, subclasses 33+ barrier layer stock material and subclasses 400+, stock. 8. Class 75, subclasses 331+, processes of making solid partiuclate alloys directly from liquid metal and subclasses 343+, processes of producing or purifying alloys in powder form. 9. Class 75, subclasses 10.1+ and 10.67, processes of making alloys by electrothermic, electromagnetic, or electrostatic processes. 10. Class 420, Alloys or Metallic Compositions, processes of manufacture. 11. Class 75, subclasses 330+, processes of making metal and processes of treating liquid metals and liquid alloys and consolidating metalliferous material. 12. Class 204, Chemistry: Electrical and Wave Energy, processes. 13. Class 164, Metal Founding, subclasses 1+, processes. 14. Class 266, Metallurgical Apparatus, subclasses 44+, processes of operating metallurgical apparatus. This list is not complete and may be added to as the proper relationship of other areas is determined. See References to Other Classes, below for classes speficially related to Metallurgical And Metallic Stock Classes. ARTICLE CLASSES. The former rule known as the alloy "rule" has been abolished. Patents claiming an article by name only without any positive structural limitation and reciting the alloy, or metallic composition of which the article is made are properly classifiable in this class (420). This is true whether, or not the alloy, or metallic composition is claimed, per se, or whether it has specific properties making it particularly suitable for such article. There are, however, some article areas which have not yet as of 1981 been brought into conformance with this line. For these exceptions note is made to the list in the class definition of Class 106, Composition: Coating or Plastic, under (1) Note, section (b). See References to Other Classes, below for classes speficially related to Article Classes. |