C23DENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS C23D1/00 C23D1/00Melting or fritting the enamelsApparatus or furnaces therefor C23D1/02Granulating the meltDrying the granules C23D3/00Coating with the enamels C23D3/00Chemical treatment of the metal surfaces prior to coating C23D5/00Coating with enamels or vitreous layers C23D5/005by a method specially adapted for coating special objects C23D5/02by wet methods C23D5/04by dry methods C23D5/06producing designs or letters C23D5/08Applying enamels non-uniformly over the surface C23D5/10with refractory materials Group C23D5/10 is no longer used for classification. Documents are in the state of being reclassified to C23C4/10 and C23C24/10. C23D7/00Treating the coatings, e.g. drying before burning C23D9/00Firing the enamels C23D9/00Ovens specially adapted for firing enamels C23D9/02Non-electric muffle furnaces C23D9/04Non-electric tunnel ovens C23D9/06Electric furnaces C23D9/08Supporting devices for burning-bars C23D9/10Loading or unloading devices C23D11/00Continuous processesApparatus therefor C23D13/00After-treatment C23D13/00After-treatment of the enamelled articles C23D13/02Removing defects by local re-melting of the enamelAdjusting the shape C23D15/00Joining enamelled articles to other enamelled articles by processes involving an enamelling step C23D17/00De-enamelling