SIST EN 15826:2010
(Main)Vitreous and porcelain enamels - Terminology
Vitreous and porcelain enamels - Terminology
This European Standard defines a number of terms relating to vitreous and porcelain enamels and their technology. This list is not complete and only comprises those terms for which the definition is considered necessary for correct and adequate understanding in order to clarify these processes. It should be understood that the interpretations given are those corresponding to the practical usage in this field and that they do not necessarily coincide with those used in other fields. For purposes of clarification, the term Vitreous Enamel, used throughout this European Standard, is synonymous with Porcelain Enamel, the term favoured in the United States and some other countries.
Emails und Emaillierungen - Terminologie
Diese Europäische Norm definiert eine Reihe von Begriffen, Emails und Emaillierungen sowie zugehörige
Technologien betreffend. Die Auflistung der Begriffe ist nicht vollständig und umfasst nur die Begriffe, deren
Definition für ein richtiges und ausreichendes Verständnis zur Erläuterung der betreffenden Prozesse als
notwendig erachtet wird.
Es sollte berücksichtigt werden, dass die angeführten Erläuterungen praxisnah für das Gebiet der Emails und
Emaillierungen sind und dass sie nicht zwangsläufig denen entsprechen, die auf anderen Gebieten verwendet
werden.
Zur besseren Übersichtlichkeit steht der englischsprachige Begriff „vitreous enamel“, der in dem
(englischsprachigen) Dokument durchgängig verwendet wird, gleichbedeutend für den in den Vereinigten
Staaten und einigen anderen Ländern bevorzugt verwendeten Begriff „porcelain enamel“.
Emaux vitrifiés - Terminologie
La présente Norme européenne définit un certain nombre de termes relatifs aux émaux vitrifiés et à leur
technologie. La liste n’est pas exhaustive et ne comprend que les termes dont la définition est considérée
comme nécessaire à la bonne compréhension, afin de clarifier ces processus.
Il convient de noter que les interprétations données sont celles qui correspondent à l’usage pratique dans ce
domaine, et qu’elles ne coïncident pas nécessairement avec celles d’autres domaines.
A titre de clarification, le terme anglais vitreous enamel, utilisé dans tout le document anglais, est synonyme
du terme anglais porcelain enamel, qui est le terme usité aux Etats-Unis et dans certains pays.
Steklasti in keramični emajli - Terminologija
Ta evropski standard določa število izrazov v zvezi z steklastimi in keramični emajli ter njihovimi tehnologijami. Ta seznam ni popoln in vsebuje samo tiste izraze, za katere velja, da je potrebna definicija za pravilno in primerno razumevanje z namenom razjasnitve teh procesov. Upoštevati je treba, da podane razlage ustrezajo praktični uporabi na tem področju in da ni nujno, da sovpadajo z razlagami, ki se uporabljajo na drugih področjih. V pojasnitev je izraz steklasti emajl, ki se uporablja povsod v tem evropskem standardu, in je sinonim za keramični emajl, ki je bolj priljubljen izraz v Združenih državah in nekaterih drugih državah.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Emails und Emaillierungen - TerminologieEmaux vitrifiés - TerminologieVitreous and porcelain enamels - Terminology25.220.50Emajlne prevlekeEnamels01.040.25Izdelavna tehnika (Slovarji)Manufacturing engineering (Vocabularies)ICS:Ta slovenski standard je istoveten z:EN 15826:2009SIST EN 15826:2010en,fr,de01-marec-2010SIST EN 15826:2010SLOVENSKI
STANDARD
SIST EN 15826:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15826
December 2009 ICS 01.040.25; 25.220.50 English Version
Vitreous and porcelain enamels - Terminology
Émaux vitrifiés - Terminologie
Emails und Emaillierungen - Terminologie This European Standard was approved by CEN on 7 November 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15826:2009: ESIST EN 15826:2010
EN 15826:2009 (E) 2 Contents Page Foreword .31Scope .42Terms and definitions .4Annex A (informative)
Cross reference index of alternative terms . 28 SIST EN 15826:2010
EN 15826:2009 (E) 3 Foreword This document (EN 15826:2009) has been prepared by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2010, and conflicting national standards shall be withdrawn at the latest by June 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 15826:2010
EN 15826:2009 (E) 4
1 Scope This European Standard defines a number of terms relating to vitreous and porcelain enamels and their technology. This list is not complete and only comprises those terms for which the definition is considered necessary for correct and adequate understanding in order to clarify these processes. It should be understood that the interpretations given are those corresponding to the practical usage in this field and that they do not necessarily coincide with those used in other fields. For purposes of clarification, the term Vitreous Enamel, used throughout this European Standard, is synonymous with Porcelain Enamel, the term favoured in the United States and some other countries. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. NOTE Annex A lists alternative terms and cross refers to primary terms used below. 2.1 abrasive blasting process for cleaning or finishing by means of an abrasive directed at high velocity against the work piece 2.2 abrasion resistance degree of resistance of vitreous enamel to be abraded by solid materials 2.3 acid resistance degree of resistance of vitreous enamel to attack by acidic corrosive chemicals 2.4 adherence (enamel-metallic substrate) adhesion degree of bonding between the fused vitreous enamel and the metallic substrate 2.5 adherence of powder ability of a vitreous enamel powder to remain attached by static attraction to a grounded substrate before firing 2.6 ageing change in properties of vitreous enamel slips, powders, reagents, or steel with the lapse of time 2.7 air seal air curtain flow of pressurised air across the entrance and exit of a continuous furnace that prevents heat escaping from the furnace but allows ware to pass through 2.8 alkali degreasing removal of oil, grease, lubricants, and loose debris from the surface of the metallic substrate by immersion or spraying with an aqueous alkali degreaser in preparation for vitreous enamelling SIST EN 15826:2010
EN 15826:2009 (E) 5 2.9 alkali resistance degree of resistance of vitreous enamel to attack by alkaline corrosive mediums 2.10 aluminium enamel vitreous enamel specifically formulated for application on aluminium substrates 2.11 anneal annealing thermal treatment of metals generally made by controlled heating and subsequent cooling NOTE Raw castings are heated in the range from 650 °C to 950 °C to relieve stresses and strains, burn off grease and in some cases to change the structure of the iron and in so doing improve the castings condition prior to coating with vitreous enamel. 2.12 anti-scale compound agent that is applied to furnace tooling and other items to protect them from scaling during firing 2.13 back emission back ionisation (electrostatic powder) defect often with the appearance of localised, very heavy orange peel, due to excessive charge build-up in the powder film resulting in electrical breakdown of air (i.e. back emission) NOTE The effect of the self-limiting characteristics of the electrostatic powder, during application. 2.14 ball mill ceramic or ceramic-lined rotating cylinder in which vitreous enamel materials are either wet or dry ground, generally using alumina, porcelain or steatite balls as grinding media 2.15 batch smelter discontinuous smelter smelter which is charged, fired, and discharged according to a predetermined periodic cycle 2.16 bead defect resulting from accumulation of enamel usually at the point where the enamel drains off the ware in dipping 2.17 beading rim enamelling application of ridge of vitreous enamel, along the edge or rim of ware 2.18 beading enamel rim enamel vitreous enamel specifically formulated for beading 2.19 biocide anti-bacterial agent used to inhibit fermentation of organic mill additions such as gums SIST EN 15826:2010
EN 15826:2009 (E) 6 2.20 bisque dry unfired vitreous enamel coating 2.21 black specks defect that appears as black particles at the surface of vitreous enamel coating
NOTE 1 See boiling (2.26) and carbon boil (2.34). NOTE 2 This can be the result of reaction with the substrate or with contamination on the substrate surface. 2.22 blank sized piece of untreated metal sheet that will be used in forming the finished article 2.23 blasting process whereby solid metallic, mineral, synthetic resin, vegetable particles or water are projected at high velocity against a work piece for the purpose of cleaning, abrading or shot peening the surface 2.24 blister defect that appears as a localised bubble under the surface of the fired vitreous enamel 2.25 bloom visual exudation or efflorescence on the vitreous enamel surface NOTE See scumming (2.212). 2.26 boiling defect resembling areas of ground-coat pull-through, blisters and pinholes, visible after first cover-coat fire NOTE 1 See carbon boil (2.34) and black specks (2.21). NOTE 2 This can be the result of excessive ground-coat activity during cover-coat fire, as the ground-coat boils up through the cover-coat it maybe accompanied by a release of gases. 2.27 bolt-hole brush specially designed round brush used to remove vitreous enamel bisque from in and around small openings in the ware 2.28 box furnace furnace in which ware is fired according to a predetermined periodic cycle 2.29 break out defect characterised by areas of blisters, having well-defined boundaries 2.30 bubble structure size and spatial distribution of voids within the fired vitreous enamel layer SIST EN 15826:2010
EN 15826:2009 (E) 7 2.31 burn-off defect that appears as a localised area of rough oxides erupting through the enamel coating NOTE This can be caused by too thin an application of enamel, allowing excessive oxidation of the metal substrate during firing, leading to super saturation of the enamel coating with metal oxides. 2.32 burning bar burning point burning tool tool used to suspend or support ware during firing operations 2.33 button test fusion button test control test to determine the relative fusibility of vitreous enamel frit or powder NOTE 1 See fusion flow test (2.126). NOTE 2 The completed test specimen resembles a button. 2.34 carbon boil defect resembling areas of blisters, pinholes, or black specks, visible in fired vitreous enamel
NOTE 1 See boiling (2.26) and black specks (2.21). NOTE 2 Result of the oxidation of carbides and free carbon at or near the surface of the steel substrate during firing, resulting in evolution of gasses. 2.35 cascading
defect that starts with a few particles of powder detaching themselves after application and as they cascade down the ware they gather more and more powder leaving a trail of thinner and thinner coating NOTE Excess powder, inadequate powder adhesion and vibration contribute to this defect. 2.36 cast iron enamel vitreous enamel specifically formulated for application on cast iron substrate 2.37 cermet ceramic-metal coating mixture of one or more ceramic materials in combination with a metallic phase applied to a metallic substrate 2.38 chalkboard enamel blackboard enamel special type of matt vitreous enamel, used to provide a writing surface for chalk 2.39 chalky surface surface defect where the vitreous enamel surface has lost its gloss and taken on a powdery appearance
NOTE See scumming (2.212). SIST EN 15826:2010
EN 15826:2009 (E) 8 2.40 chemical resistance degree of resistance of vitreous enamel to attack by corrosive chemicals 2.41 chipping defect characterised by fracturing and detachment of irregular enamel particles from the vitreous enamel surface 2.42 cleanability relative ease with which soils or stains can be removed from a fused vitreous enamel surface 2.43 cleaner pre-treatment solution, usually alkaline, used to remove oil, grease, lubricants, and loose debris from the surface of metal substrate in preparation for vitreous enamelling 2.44 cleaning degreasing vapour degreasing removal of foreign materials, such as abraded metallic particles from pressing or blasting, grease, oil, oxides, scale, rust, swarf, etc. from the surface 2.45 clear frit transparent frit vitreous enamelling frit that remains essentially transparent or non-opaque when fused 2.46 coefficient of expansion rate at which a material will expand under the influence of increasing temperature 2.47 cold-rolled steel low carbon, cold-reduced and annealed sheet steel, not necessarily enamelling quality 2.48 colour matching comparison of two or more samples of products that are notionally the same colour 2.49 colouring oxide calcined mixture of inorganic material used as a mill addition to impart colour to a vitreous enamel 2.50 coloured frit vitreous enamel frit containing a colorant in order to produce a strong colour in the fired vitreous enamel 2.51 consistency rheological properties of a vitreous enamel slip that control its draining, flowing, and spraying behaviour 2.52 continuity of coating degree to which a vitreous enamel is free from defects such as bare spots, boiling, blisters, or copperheads, etc. that could reduce its protective and/or its aesthetic properties
SIST EN 15826:2010
EN 15826:2009 (E) 9 NOTE See discontinuity (2.82). 2.53 continuous furnace furnace through which ware is fed continuously and from which the fired product is discharged continuously 2.54 continuous smelter smelter from which the molten product is discharged continuously 2.55 conventional enamelling application of vitreous enamel ground coat(s) and cover coat(s), each one followed by a firing operation 2.56 cooling zone exit part of a continuous furnace in which the ware is allowed to cool after firing 2.57 copper enamels vitreous enamels specifically formulated for application on copper substrate 2.58 copperheads defect resembling small freckle or pimple-like reddish brown spots occurring in ground-coats, or direct-on enamels on iron substrates, in principle in an isolated round burn-off NOTE See burn-off (2.31). 2.59 cover coat enamel vitreous enamel with specific chemical, physical and/or aesthetic properties applied as either intermediate or final coat 2.60 covering power degree to which a vitreous enamel coating obscures the underlying surface 2.61 crack cracking defect caused by laminar interruptions in the fused coating running vertical to the surface NOTE 1 Cracking can also occur at different angles. NOTE 2 The causes are mainly the result of mechanical or thermal tensile stresses within the enamel coating. 2.62 crawling curling incomplete formation of the enamel layer on the substrate with the appearance of agglomerates or irregularly spaced islands in the vitreous enamel during firing 2.63 crazing defect resembling a network of fine cracks in the vitreous enamel coating SIST EN 15826:2010
EN 15826:2009 (E) 10 2.64 cross-bend test determination of the resistance of bisque or fused vitreous enamel coating to cracking by progressively distorting the coated panels by bending 2.65 cup spray gun cup-gun spray gun with a fluid container as an integral part 2.66 cupping pouring of vitreous enamel slip over areas of a component during draining, to improve coverage in certain areas 2.67 curtains defect with the appearance of a draped pattern of darkened areas that sometimes blisters NOTE Curtains occur mainly in ground-coats and direct-on enamels but may also be seen in cover coats. 2.68 decal transfer design or wording printed on paper with ceramic ink and transferred to a fired enamel surface and then refired to form an integral part of the vitreous enamel coating 2.69 decarburised steel zero carbon steel special type of steel sheet of extremely low carbon content NOTE 1 This type of steel is suitable for direct-on white cover-coat application after acid pickle and nickel flash. NOTE 2 De-carburised steel does not undergo a permanent phase change during firing hence it is sag resistant and is therefore suitable for large panels, etc. 2.70 de-beading removal of excess vitreous enamel slip from the edge of dipped ware 2.71 decking multiple layer loading of ware for drying and/or firing 2.72 de-enamelling removal of fired vitreous enamel from the metallic substrate 2.73 de-setting agent electrolytes that reduce the viscosity of the vitreous enamel slip 2.74 delayed fish-scale small half-moon shaped defects occurring in the vitreous enamelled surface which are not immediately apparent on cooling NOTE See fish-scale (2.116). SIST EN 15826:2010
EN 15826:2009 (E) 11 2.75 de-vitrification change from the vitrified state to the crystalline state NOTE Some vitreous enamels will de-vitrify to produce dull lustre and opacity. 2.76 dimple defect resembling a shallow depression in the vitreous enamel surface 2.77 dip weight pick-up
plate weight amount of vitreous enamel retained on a test plate after dipping, flow coating or by slushing NOTE This is specified as either dry weight or wet weight retained per unit area on a test plate. 2.78 dipping (wet process) swilling (wet process) application of vitreous enamel by immersing the component in a bath of vitreous enamel slip, and subsequent removal of excess enamel by draining 2.79 dipping (dry process) application of vitreous enamel in dry process enamelling by briefly immersing the red hot component in powdered frit 2.80 direct fired furnace open flame furnace NOTE The products of combustion come into contact with the ware during firing. 2.81 direct-on-enamelling vitreous enamel coating, applied directly onto the metallic substrate and functioning as either a ground coat or as a finish coat 2.82 discontinuity weakness within the vitreous enamel coating that is detected by spark testing 2.83 double draining evidence of further flow having occurred after the apparent end of draining 2.84 double-face ware ware that has a finish coating on both surfaces 2.85 drain line defect resembling a streak of thicker or thinner enamel NOTE Drain lines result from the flow of excess enamel after dipping. SIST EN 15826:2010
EN 15826:2009 (E) 12 2.86 drain time time required for vitreous enamel slip applied by dipping, slushing, or flow coating, to complete its movement across the surfaces of a coated part 2.87 draining removal of excess vitreous enamel slip from the ware after dipping, slushing or flow coating 2.88 dredge sieve used to apply powdered vitreous enamel frit to hot ware in dry process enamelling 2.89 dry milling dry grinding milling/grinding of vitreous enamel materials in the absence of liquid 2.90 dry process enamelling process whereby cast iron components are heated to a temperature above the maturing temperature of the vitreous enamel, then coated with vitreous enamel powder by hot dusting/dredging or dipping and subsequently fired 2.91 dry spray appearance of a rough sandy texture on spray coated ware NOTE Dry spray is the result of not wetting out the wet sprayed surface. 2.92 dry weight weight of the vitreous enamel bisque, per unit area
NOTE See dip weight (2.77). 2.93 drying crack defect characterised as a fissure in the bisque, visible after firing 2.94 dulling lustreless finish to the vitreous enamelled surface 2.95 dust coat relatively thin, sprayed coating of vitreous enamel slip 2.96 easy-to-clean enamel ETC enamel vitreous enamel specifically formulated to allow the easy removal of food soil deposits from its surface NOTE ETC enamel needs to be neither pyrolytic nor catalytic. 2.97 edging process of removing vitreous enamel bisque from the edge of a piece of ware to expose the underlying vitreous enamel SIST EN 15826:2010
EN 15826:2009 (E) 13 or spraying of special slip onto the edge of the ware 2.98 edging brush stiff bristled brush with a metal guide, used for removal of vitreous enamel bisque from edges of ware before the firing operation 2.99 eggshell fused vitreous enamel surface exhibiting a smooth, matt texture, reminiscent of an egg shell NOTE In sanitary ware it is a defect. 2.100 electrophoretic deposition deposition of vitreous enamel particles onto a work-piece from an enamel slip under the influence of an applied direct current voltage 2.101 electrostatic dry powder application process in which the component is coated by electrostatically charged vitreous enamel powder 2.102 electrostatic wet application process in which the component is coated by electrostatically charged vitreous enamel slip 2.103 enamelling aluminium aluminium suitable for use as a metallic substrate for vitreous enamelling 2.104 enamelling cast iron cast iron suitable for use as a metallic substrate for vitreous enamelling 2.105 enamelling iron cold reduced low carbon steel, specifically produced as a metallic substrate for vitreous enamelling 2.106 etched loss of gloss and/or roughening of the surface as a result of chemical attack 2.107 Faraday cage effect
defect resulting from poor penetration by charged enamel particles into concave areas leading to thin spray and potentially to burn-off 2.108 film strength relative resistance of the vitreous enamel bisque to mechanical damage NOTE See cross-bend test (2.64). 2.109 fineness test control test used to measure the degree to which a vitreous enamel frit has been milled in either the wet or dry form, usually expressed in grams residue retained on a particular mesh sieve from a given sample size SIST EN 15826:2010
EN 15826:2009 (E) 14 2.110 fire tool marks burning tool marks fire marks pin marks point marks defect characterised by very small indentations similar in appearance to shallow pinholes NOTE Fire tool marks may also appear on the surface opposite to the point of contact with the supporting tool. 2.111 firing controlled heat treatment of vitreous enamelled ware in a furnace, in order to fuse and develop the coating’s desired properties 2.112 firing range time-temperature interval in which a vitreous enamel or ceramic coating is satisfactorily fused 2.113 firing temperature maturing temperature temperature at which vitreous enamel must be held for a selected time to achieve the desired properties 2.114 firing time period of time during which the ware remains in the firing zone of the furnace to mature the vitreous enamel coating 2.115 firing zone portion of the furnace, usually a continuous furnace, through which the ware passes during the firing time 2.116 fish-scale small half-moon shaped defects occurring in the vitreous enamelled surface NOTE 1 See delayed fish-scale (2.74), shiner-scale (2.219), whale-scale (2.257) and process fish-scale (poppers) (2.184). NOTE 2 Fish-scaling can occur immediately on cooling or after some time has elapsed following firing. This defect originates from super saturation of the substrate with hydrogen (acquired during firing), which explosively fractures the enamel coating in order to relieve the pressure that has accumulated with time at the enamel-steel interface. 2.117 flaw defect in ware causing rejection 2.118 flow button pellet of compressed powdered frit used in the "fusion flow test" 2.119 flow coating process of coating a metal shape by causing the slip to flow over its surface, and allowing it to drain SIST EN 15826:2010
EN 15826:2009 (E) 15 2.120 fluidity ability of a powder to develop a fluid-like consistency and flow properties when aerated 2.121 flux substance that interacts with infusible (or partially infusible) materials, thus increasing fluidity of the melted mix 2.122 ford cup device for measuring the flow out time for a defined volume through a specified area (hole) 2.123 fork tool used to load and remove ware from the furnace during the firing operation 2.124 frit
flake result of fusing a mixture of different inorganic raw materials, which constitute the vitrifiable base of the enamel, molten at temperatures between 1 150 °C and 1 350 °C and then quenched the molten glassy mass from these temperatures NOTE Granulated frit is produced by quenching the discharging melt into water and flake is produced by discharging the melt between water cooled rollers. 2.125 fritting process of quenching and shattering molten glass into small friable frit particles 2.126 fusion flow test control test to compare the relative fluidity behaviour of molten samples of frit compared to an accepted standard 2.127 galvanic nickel dip deposition of a nickel coating produced by a displacement reaction in which one metal displaces another from solution EXAMPLE Fe + Ni++ : Ni + Fe++ 2.128 gasatura gassing grizzle spongy enamel defect in which the vitreous enamel surface is disfigured by a myriad of minute bubbles or blisters, some broken and accompanied by a loss of gloss NOTE The condition is associated with the evolution of hydrogen, principally originating from moisture. 2.129 glass term sometimes used for vitreous enamel or frit, in particular by chemical vessel manufacturers 2.130 glass eye defect consisting of large unbroken blister in the surface of the fused vitreous enamel SIST EN 15826:2010
EN 15826:2009 (E) 16 2.131 gloss shine or lustre of vitreous enamel surface 2.132 graining application of a vitreous enamel finish resembling wood grain 2.133 graining roller specialised type of roller used for transferring a grain pattern to the vitreous enamel 2.134 grit blasting process for cleaning and abrading the surface by means of small irregular pieces of steel or malleable cast iron directed at high velocity against the work piece NOTE In the United Kingdom, this term can also apply to the use of non-metallic particles of similar shape, e.g. silicon carbide or aluminium oxide. 2.135 ground-coat vitreous enamel applied directly to the substrate to function as an intermediate bonding layer between the substrate and the cover coat 2.136 hairlines strain-lines tension-lines defect resembling one or a series of near parallel lines in the fused vitreous enamel surface, and giving the appearance of cracks healed by fusion NOTE Hairlines can be caused, for example by the release of mechanical stresses within the steel during firing. 2.137 hardness relative refractoriness of a vitreous enamel or frit 2.138 hollow ware cookware
ovenware kitchen utensils such as pots, pans, and kettles 2.139 hot dusting dredging application of dry powdered frit to red hot ware by sifting 2.140 impact test test to determine the resistance of a vitreous enamel to fracture from a sudden blow 2.141 jar mill pot mill small porcelain ball mill SIST EN 15826:2010
EN 15826:2009 (E) 17 2.142 jewellers' enamel vitreous enamel specifically formulated for use in the manufacture of jewellery, insignia, and art objects 2.143 lamination
defect characterised by a linear row of blisters in the vitreous enamel surface along the direction of rolling, in severe cases a metal blisters will form 2.144 lump defect characterised by rounded projection on an enamelled surface NOTE A lump is commonly the result of spray-gun spit. 2.145 lustre
decorative surface finish with an iridescent appearance or pearly or silky sheen of a vitreous enamel surface 2.146 marble effect decorative surface finish produced by colouring and graining that resembles variegated marble however in the case of white enamels often noted as a defect due to a lack of opacity 2.147 matt enamel vitreous enamel specifically formulated to provide a surface with low specular gloss NOTE Matt enamel is also used to express a lack of gloss. 2.148 medium
squeegee oil oil or mixture of oils used to suspend pigments and fluxes in screening inks 2.149 metal blister defect with the appearance of a bulge in the enamelled surface due to entrapped gasses in a steel lamination resulting in localised swelling in the metal substrate during firing NOTE Historically, metal blisters originated from pipe lamination in ingot route steel. 2.150 mill additions materials used to prepare enamel slip, such as bisque strengtheners, electrolytes, pigments, refractories and suspension agents, etc. and which together with the frit comprise the mill charge 2.151 millscale thick oxide layer formed during hot rolling or heat treatment of certain metals 2.152 mottled ware graniteware decorative finish with particles of one colour appearing in a uniform background of another colour or shade
SIST EN 15826:2010
EN 15826:2009 (E) 18 NOTE See self-mottled ware (2.214). 2.153 muffle furnace refractory chamber heated from the outside NOTE The heat is transferred through the walls of the firing chamber in order to fire the ware inside and hence the ware has no contact with the products of combustion. 2.154 neutraliser agent used to remove excess acid or alkali remaining on the surface of the work piece after pre-treatment 2.155 nickel dip chemical deposition of a discontinuous layer of metallic nickel on to the surface of the steel in order to enhance the steel/enamel bond NOTE See galvanic
nickel dip (2.127) and reduction nickel dip (2.192). 2.156 one-coat enamelling vitreous enamelling of ware is completed in a single coat application 2.157 one-fire enamelling coat or coats of vitreous enamel fused in a single fire 2.158 opacifier material that imparts or increases the opacity of vitreous enamel 2.159 opaque vitreous enamel vitreous enamel frit which exhibit opaque properties after firing, through which neither the underlying coating or substrate is visible 2.160 orange peel defect in the fused enamel coat showing a dimpled or wavy surface characteristic of orange peel 2.161 over-spray slip from the spray gun not deposited on to the target area of the ware or spray application of a light coat of slip to an unfired vitreous enamel 2.162 pearl lines bubble lines defect characterized by a number of bubbles or blisters in a single line or a series of parallel lines NOTE 1 This is a severe case of strain-lines and is a result of the release of mechanical stresses within the steel during firing. NOTE 2 Pearl lines should not be confused with the out-gassing from steel lamination which occurs as a single line along the direction of rolling - see lamination (2.143). SIST EN 15826:2010
EN 15826:2009 (E) 19 2.163 peeling defect characterised by spontaneous detachment of large pieces of vitreous enamel from the metallic surface after f
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