1、BRITISH STANDARDBS EN ISO 14924:2005Thermal spraying Post-treatment and finishing of thermally sprayed coatingsThe European Standard EN ISO 14924:2005 has the status of a British StandardICS 25.220.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40
2、g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 14924:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 6 October 2005 BSI 6 October 2005ISBN 0 580 46656 6National forewordThis B
3、ritish Standard is the official English language version of EN ISO 14924:2005. It is identical with ISO 14924:2005.The UK participation in its preparation was entrusted to Technical Committee STI/40, Thermally sprayed inorganic finishes, which has the responsibility to: A list of organizations repre
4、sented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”,
5、or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer im
6、munity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them i
7、n the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, pages 2 to 14, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. N
8、o. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 14924August 2005ICS 25.220.20English VersionThermal spraying - Post-treatment and finishing of thermallysprayed coatings (ISO 14924:2005)Projection thermique - Traitement et finition desrevtements obtenus par projection thermique
9、(ISO14924:2005)Thermisches Spritzen - Nachbehandeln undNachbearbeiten von thermisch gespritzten Schichten (ISO14924:2005)This European Standard was approved by CEN on 14 April 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving thi
10、s EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (Engl
11、ish, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech
12、 Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALI
13、SATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 14924:2005: E2 Contents page Foreword3 1 Scope 5 2 Normative references 5 3 Mechanica
14、l post treatment .5 4 Chemical treatment7 5 Thermal treatment8 6 Health and safety .9 Annex A (informative) Some estimated values for chip cutting of thermally sprayed coatings.10 Annex B (informative) Some estimated values for grinding of thermally sprayed coatings.12 Annex C (informative) Informat
15、ion on abrasives .14 EN ISO 14924:20053 Foreword This European Standard (EN ISO 14924:2005) has been prepared by Technical Committee CEN/TC 240 “Thermal spraying and thermally sprayed coatings”, the secretariat of which is held by DIN, in collaboration with Technical Committee ISO/TC 107 “Metallic a
16、nd other inorganic coatings”. 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 February 2006, and conflicting national standards shall be withdrawn at the latest by February 2006. According to the
17、CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembou
18、rg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN ISO 14924:20054 Introduction The successful service of a thermally sprayed component depends decisively on the right choice of procedure for post treatment and/or finishing after s
19、praying. In order to work and/or to treat a thermally sprayed coating especially the property of the lamellae structure needs to be taken into account. The structure is quite different from those of the same materials in the cast or wrought state and finishing techniques which may be suitable in the
20、se latter cases would be likely to damage thermally sprayed coatings. EN ISO 14924:20055 1 Scope This European Standard specifies the treatment and finishing of thermally sprayed coatings. It is applicable to different types of mechanical post treatment, chemical treatment, and thermal treatment, in
21、cluding chip cutting and other mechanical processes, to sealing, pickling and painting, and fusing, diffusion annealing and hot isostatic pressing. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition
22、 cited applies. For undated references the latest edition of the referenced document (including any amendments) applies. EN ISO 2063, Thermal spraying - Metallic and other inorganic coatings - Zinc, aluminium and their alloys (ISO 2063:2005) EN ISO 12944-5, Paints and varnishes Corrosion protection
23、of steel structures by protective paint systems Part 5: Protective paint systems (ISO 12944- 5:1998) EN ISO 14920, Thermal spraying Spraying and fusing of self-fluxing alloys (ISO 14920:1999) ISO 504, Turning tools with carbide tips Designation and marking 3 Mechanical post treatment 3.1 Chip cuttin
24、g 3.1.1 General For the reasons stated in the Introduction, the common basis of chip cutting techniques cannot be applied to thermally sprayed coatings because of their different properties. There are many different hard phases in sprayed coatings such as oxides, carbides, borides, silicides and oth
25、ers. These require specific attention to the geometry of the cutting edge to prevent high wear of the flank. 3.1.2 Turning The possibility of turning a thermally sprayed metal coating depends upon the specific property of a thermal spray coating e.g. structure and hardness as well as any previously
26、applied thermal spray process. a) Tool selection: Due to hard phases in metallic thermal spray coatings and the partly extremely hardening spray particle the turning tool is more heavily loaded compared to cast or forged material consisting out of the same or similar material. Because of this reason
27、 hard metals and ceramic cutting materials are required. The ones commonly used for turning grey cast iron, chilled cast iron and short cutting chip malleable cast iron. In contrast thermally sprayed aluminium or copper coatings can be turned economically using high speed steel cutting tools. Good o
28、peration times are achieved by using hard metal quality K01 and K10 according to ISO 504. Thermally sprayed coatings with hardnesses x 700 HV (60 HRC) may be turned satisfactorily using boron nitride tools, consisting of poly-crystalline, cubic boron nitride (CBN), which are sintered to a hard metal
29、 body. Thermally sprayed copper and aluminium coatings can be turned economically using high-speed steel. b) Cutting speed: EN ISO 14924:20056 The optimum cutting speeds for thermal spray coatings are different. They are lower because of embedded hard phases compared to homogeneous materials and req
30、uire sharp cutting tools with cutting radius R 0,4 mm - 1,2 mm. Tables A.1 to A.4 show approximate values which may be adjusted from case to case. A test cut is recommended in order to avoid unfavourable results. NOTE Applying excessive cutting velocities the thermal spray coating acts like a lappin
31、g tool causing an uneconomic lifetime of the tool. The blunt cutting tool generates a high surface load and can lead to coating damage. c) Traverse feed: Traverse feed per revolution shall be of the order of particle diameter of thermal spray coating. Tables A.1 to A.4 show approximate values for tu
32、rning of thermally sprayed metal coatings which may be adjusted from case to case. 3.1.3 Milling In some cases thermal spray coatings may be machined also by milling. Concerning selection of tool and choice of feed and speed the same considerations as for turning shall be taken into account. 3.1.4 C
33、ooling during chip cutting operations When coatings of self-fluxing alloys, which are fused to provide a dense structure, are machined, a coolant may be used in order to prevent overheating (This does not apply when CBN cutting tools are used). Otherwise a coolant shall not be used when as sprayed c
34、oatings (which are not fused) are being machined. The micro porosity of the coating permits penetration of the coolant causing discolouration and other problems. If coolant is used areas of high hydraulic pressure can wholly or partially remove particle giving a poor surface finish. 3.1.5 Grinding 3
35、.1.5.1 General Wet grinding shall be preferred to dry grinding in order to avoid over heating of the thermally sprayed coating as well as of the work piece. 3.1.5.2 Preparation It is advantageous to seal the coating before grinding. This will prevent penetration of the coolant to the interface with
36、the substrate material causing possible corrosion problems (see 4.1). It will also minimise the generation of grinding debris which may contaminate the returned coolant. Care should be taken to the choice of sealant, so that the sealant do not get burnt or smeared onto the grinding wheel, due to the
37、 sometimes high contact temperatures during grinding. Additionally, sealing of ceramic coatings is also preferred before grinding to prevent unsightly staining of the coating due to penetration of the coolant. 3.1.5.3 Selection of grinding process All thermally sprayed coatings may be ground. The lo
38、ading of the thermally sprayed coating is lower compared with that of turning. Tables B.1 and B.2 show details for grinding. 3.1.5.4 Selection of grinding wheel The shape of the grinding wheel will vary depending on the geometry of the component to be ground. e.g. cup wheels may be used where approp
39、riate. Dry grinding may be carried out although the use of a coolant, where possible, is preferred. EN ISO 14924:20057 Tables B.1 to B.3 show the kind of wheels to be used, which will depend on the thermal spray material used. 3.1.5.5 Belt grinding Where a smooth finish is required and dimensional a
40、ccuracy is not important, belt grinding may be used. Typically silicon carbide or diamond belts are used for this purpose. 3.1.6 Other cutting processes 3.1.6.1 Chip cutting with geometrically defined tool edges (drilling) Certain thermal spray coatings can be drilled using sharp spiral drills. 3.1.
41、6.2 Planning, sawing, reaming, broaching Precautions shall be taken when using these processes due to the risk of damaging the coatings. 3.1.6.3 Chip cutting with geometrically undefined but hard tool edges a) Abrasive cutting, honing: For these cutting processes the same recommendations as for grin
42、ding shall be taken into account. b) Applying loose grains: Polishing, lapping: Polishing of ground or turned metallic thermally sprayed coatings may be carried out by using polishing machines and applying polishing filler materials. A heat build up shall be avoided to prevent coating damage. Super
43、finishing: Thermal Spray coatings especially ceramic coatings (e.g. Cr2O3, Al2O3/TiO2, blends of these respectively alloys with other ceramics as well as hard materials) can be super finished in order to achieve very low coating roughness (Radown to 0,05). These results can be achieved by using appr
44、opriate powders, thermal spray equipment and wet operating finishing procedures. 3.2 Other mechanical processes 3.2.1 Shot peening In special case metallic thermal sprayed coatings can be post-treated by shot peening. The shot peening process densifies the coating and can generate a compressive stre
45、ss. This post-treatment can increase the corrosion resistance of especially arc and flame sprayed coatings. Care has to be taken that the thermally sprayed coating is not too highly loaded locally during shot peening to avoid spalling. 3.2.2 Brushing Thermal sprayed coatings can be brushed in order
46、e.g. to smooth the surface, to remove spray dust to achieve clean surfaces or decorative effects. 4 Chemical treatment 4.1 Sealing 4.1.1 General Untreated thermally sprayed coatings contain micro porosity. In many cases it is desirable to close the pores using specially formulated sealing materials
47、which will penetrate the pores and not simply lie on the surface. Control of the viscosity of the sealant is vitally important in this respect. It is also important that the coating does not take up moisture or become otherwise contaminated between spraying and sealing. EN ISO 14924:20058 4.1.2 Seal
48、ing for hydraulic and pneumatic applications In order to avoid a loss of static or dynamic pressure, the pores in the coating shall be closed by applying a suitable sealant. 4.1.3 Sealing for increasing the corrosion resistance Avoiding interfacial corrosion of thermally sprayed coated components is
49、 important. Where base materials have to be coated with electrochemically more negative spray materials (e.g. steel with nickel alloys), the galvanic series is significant and has to be considered. Several sealants are available on the market such as liquid phenol resin, hard wax, anaerobic materials etc. 4.1.4 Sealing for influencing friction and sliding properties The friction and sliding coefficient of thermally sprayed coatings can be decreased by applying appropriate sealers (e.g. Poly Tetra Fluor-Ethylene (PTFE). Thus the friction and sliding properties are
