Thermal Spray Coating and Its Application in Indonesia

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Unformatted text preview: THERMAL SPRAY COATING and IT'S (POTENTIAL) APPLICATION IN INDONESIA by : BUDI PRAWARA Pusat Penelitian Tenaga Listrik dan Mekatronik Lembaga Ilmu Pengetahuan Indonesia Seminar, Workshop and The Second National Conference Coating Inspector Indonesia UNJANI Bandung, 25 April 2009 1. INTRODUCTION Terminology Thermal Spray Thermal spraying is a coating process. Thermal spraying consists of processes in which spray materials (wire or powders) are heated to the plastic or molten state, inside or outside of the spray equipment, and then accelerated towards the workpiece surface. Schematic overview thermal spray process Source : TAFA pore oxide particle unmelted particle substrate Source : Kurt H. Stern, Metallurgical and Ceramic Protective Coatings Thermal Spray Benefits Surface Treatment Original equipment enhancement Part repair and restoration Wear and Corrosion resistance Prolonged service life Cost Effectiveness Lower total cost than replacement Downtime reductions High resource utilization Less machining required Inexpensive base material option Source : TAFA Industries Utilizing Thermal Spray Aircraft/Aerospace Gas Turbine/Power Petrochemical Pulp & Paper Automotive Machine Shops Transportation Steel Marine Heavy Industry Earthmoving Electrical Many others Source : TAFA Advantages of Thermal Spray High deposition rates Low heat input process Proven technology Variety of coating materials High degree of repeatability Resource utilization Favorable economics Thermal Spray Limitations Severe No Stress Applications Impact Point loading addition in structural strength (NOT welding) Mechanical bond Permeability Coating stresses Coating thickness Surface accessible Machinability Residual Stresses quenching stresses cooling stress phase transformation stresses TECco > TECs tensile TECco < TECs compressive 2. THERMAL SPRAY TECHNIQUES Thermal Spray Processes Most Commonly Used Wire Combustion Electric Arc Spray (Twin Wire Arc) Powder Combustion Plasma Spray High Velocity Oxy-Fuel (HVOF) Thermal Spray Processes Arc Spray Process The wires are fed into a "gun" where they are electrically charged and directed together to create an arc. The resulting heat melts the wire, forming droplets that are propelled by compressed air or gas to the part surface. Source : TAFA Arc Spray Process Wire Feed Systems Electric Energy High integrity metallic and cermet coatings Versatile Fast and simple Safe Low cost Source : TAFA Enhanced Arc Spray Coatings Increasing Arc Spray Velocities Concentrating the spray stream accelerates the particles, resulting in... Up to 1200 fps (365 mps) particle velocity Narrower spray pattern Microstructures often meet aircraft quality standards Denser coatings Powder Spray Processes Powder Combustion Spray ("Flame Spray") Plasma Spray HVOF and HVAF High Velocity Process A high pressure combustion "flame" heats and propels the powder particles to the prepared substrate to create the coating. HVOF Processes Powder Feedstock Combustion Energy Oxygen-Kerosene Oxygen-Gaseous Fuel High integrity metallic & carbide coatings Particle velocity = density Low oxides High bond strength High spray rates Source : TAFA Plasma Spray Technology PLASMA An electric arc created between two fixed electrodes ionizes the gases, heating and propelling the material (usually powder) toward the workpiece. Plasma Spray Process Electric & Combustion Energy Utilizes Argon, Helium, Hydrogen, Nitrogen or Combinations High performance coatings of all types Thermal barrier (TBC) Most complicated thermal spray process Highest thermal energy Source : TAFA Plasma Process Characteristics 3. PRESPRAY TREATMENT The pieces arriving in a spraying shop are new or already coated. The new ones are usually covered with grease that protects the surface against corrosion. The used pieces have old coatings that still adhere to some of their parts. The grease and the coating must be removed in a cleaning process. A coating is to be applied on a chosen area. The remaining area should be covered with `masks' at surface activation and at spraying. Finally, immediately prior to the deposition process, the surface has to be activated. 2.1. SURFACE CLEANING Surface cleaning Substrate shaping Substrate activation Masking 3. MATERIAL USED FOR SPRAYING TYPICAL FORM Powder (metal, ceramic, cermet, polymer) Wires (metal, alloy, composite) Rod (ceramic) Classification of Powders Class 1: Restoration of Dimension and Corrosion Resistance Coating Powder Materials: Austenitic Stainless Steel Aluminium Bronze Alloy Nickel/Chromium/Molybdenum Base Superalloy for Corrosion Applications Nickel/Chromium/Iron Base Superalloy for High Temperature Applications Copper Powder for Restoration of Non-Ferrous Components Class 2: Low Temperature Tribological Coatings (applications under 540C or 1000 oF) Coating Powder Materials: Fusible Nickel Based Alloy Nickel Based Alloy/Tungsten Carbide Tungsten Carbide/Cobalt Powder for Applications Requiring a Fine As-Sprayed Surface Class 3: High Temperature Coatings (applications above 540C), Wear Resistance and Oxidation/Hot Corrosion Resistance Coating Powder Materials: Chromium Carbide/Nickel Chromium for Abrasive Fretting Wear Resistance Chromium Carbide/Nickel Chromium Chromium Carbide/Nickel Chromium for High Temperature Abrasive Wear Resistance Zirconia for TBC Class 4: Specialty Coatings Coating Powder Materials: Aluminium Alloy/Polyester Abradable Coating for Clearance Control Applications Premium Nickel Based Superalloy Powder for High Temperature Corrosion and Tribological Applications Material & Process Selection "Rules of Thumb" In terms of materials, one can apply the following: For metallic coatings, use Arc Spray For ceramic coatings, use Plasma Spray For carbide coatings, use HVOF But there are competing considerations: For highest density coatings, select HVOF For simplicity of use, select Arc Spray For maximum process flexibility, select Plasma Spray Every process has strengths and limitations. Complete Thermal Spray Systems Thermal spray device Acoustical room Dust collector Part handling Robot or X-Y Water cooling Integrated controls Source : TAFA Thermal Spray Operating Costs Material Labor and overhead Electricity Gases Other fuels (i.e. Kerosene) Consumable spare parts Water Overspray disposal Successful Coatings Concept Understanding the environment Identifying the right material Selecting the appropriate process Coating applicationPerformance Materials Characterization Thermal Spray Execution Preparing the part properly Spraying with proven parameters Handling the part carefully Finishing the coating correctly Process Optimization 5. COATING CHARACTERIZATION Thermal Spray Coating Characteristics Density Oxides Hardness (E-384-07) Bond Strength (ASTM 633-01) Microstructure Surface Finish Machinability HVOF ARC Development of a coating for a given application Growth Potential Thermal Spray as an alternative to Hard Chrome Plating Every process is suitable Longer surface/part life (3-5x) High bond (up to 10,000+ psi) Tailored material and process selection OE and repair applications Thick coating capability Fast application Reduced re-works Environmentally-friendly Alternatives to Hard Chrome Plate Surface Finish (as ground): \_____________________/ HVOF Coatings Thermal spray in Indonesia: status and the future potential application in industry Status The thermal spray processing market : Contract job shop In house production (large enterprise) Contract job shop all market size in Indonesia The wire arc spraying and flame spaying are the common thermal spray processing in workshop The common thermal spray material are metallic The future potential application in industry(1) There are many others potential applications of thermal spraying in Indonesia which can be developed to aircraft, iron & steel, petroleum-chemical, anti-corrosion, machinery, light industry, textile, automotive, paper & printing, power, shipping and many other industries. The future potential application in industry(2) The thermal spray industry in Indonesia could be developed in the following characteristics: Having large application areas and high level in certain fields Having wide range of process and materials Two thirds of the job shops are small and medium sized Thermal spraying is commonly applied to maintenance The research institutes and universities will positively entered into market and the technical development for equipment and materials are mainly carried our by them Table 1. Thermal Spraying Market Estimated Industry Output/year [5] Growth Rate (%) Thermal Spraying (potential) Market (U$) 23.2 M 27.7 M 83.3 M 14.5 M 7 9M 2.2 M 4,7 12.4 M (oil), 50 M (chemical), 13.3 M (gas) Typical Parts Iron & Steel Power Paper & Printing Textile Automobile Anti Corrosion Oil, Gas and Chemical 3,499,657 ton 73,547,000 MWh 6,968,374 ton 8221 million m3 107,912 unit 280,220 ton 1,914,639,000 m3 (gas); 432 million barrel (oil); 68,962,000 ton (chemical) 6.0 14 6.27 sink roll, hearth roll, roll-table roll, mould for CCL, furnace nozzle, fan blade, etc boiler tubes, hydraulic cylinders, blades, fans, shafts, etc. Calender rolls, dry rolls, robbin winder rolls, anilox rolls, corrugating rolls, etc. godet rolls, grooved rolls, thread guides,etc. pistons, piston rings, brake disks, synchronizing rings, etc. bridges, tanks, highways, tubes, towers, etc. MTM seals for ball, gate valves, etc. Comparing with status thermal spray in the world Thermal Spray Industry Output 39%, Other Country 35%; USA 2%, Indoneisa 2%, China 8%, Germany 14%, Japan Terima Kasih ...
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This note was uploaded on 03/17/2010 for the course ME ME78212 taught by Professor Prof.sulis during the Spring '10 term at Institut Teknologi Bandung.

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