SURFACE COATING-HARD SURFACE COATING-HARD FACING-THERMAL FACING-THERMAL

SPRAYINGSPRAYING

ByR.Venkatakrishnan

M.Tech - I - PDM

CONTENTSCONTENTS1. Introduction Of Surface Coatings

1.1 Advantages of surface coating.2.Introductions of Hard facing2.1Process

2.1.1Shielded Metal Arc Welding2.1.2Gas Metal Arc Welding2.1.3Ox fuel Welding

2.3 Process Parameters2.4 Applications2.5 Advantages

3.Introductions of Thermal Spraying3.1 Working Principle3.2 Process

3.1.1 Wire Flame Spray3.2.2 Powder Flame Spray3.2.3 Electric Arc Wire Spray3.2.4 High Velocity Oxy-Fuel

Spray (HVOF)3.3 Applications3.4 Example3.5 Advantages

1.SURFACE COATINGS1.SURFACE COATINGSSurface coatings are generally

used to avoid the resistance of the product or substrate form the environmental aspects and improve their appearance.

In many cases coatings are applied to improve the surface properties of the substrate.

1.1 Advantages of surface 1.1 Advantages of surface coating:coating:Wear resistance Corrosion resistance. Improve the life of the material Need for lubrications decreases. Surface protection against the

environment in addition to the required corrosion protection.

Hard facing is a metalworking process where harder or tougher material is applied to a base metal.Hard facing may be applied to a new part during production to increase its wear resistance, or it may be used to restore a worn-down surface.It is an surface operation to increasing the service life of the industrial components and pre-emptively on new component.

2.HARD FACING2.HARD FACING

2.1Hard facing can be 2.1Hard facing can be deposited by various welding deposited by various welding methodsmethodsShielded Metal Arc Welding (SMAW)

Gas Metal Arc Welding (GMAW)

Ox fuel Welding (OFW)

2.1.1Shielded Metal Arc 2.1.1Shielded Metal Arc Welding (SMAW)Welding (SMAW)

2.1.2Gas Metal Arc Welding 2.1.2Gas Metal Arc Welding (GMAW)(GMAW)

2.1.3Oxy fuel Welding 2.1.3Oxy fuel Welding (OFW)(OFW)

Oxy fuel welding processOxy fuel welding process

2.3PROCESS PARAMETERS2.3PROCESS PARAMETERSDiameter Amps Volts

3.25mm,1/8” 120-150 26-304.0 mm.5/32" 130-180 26-305.0mm.3/16" 180-220 26-30

TRIMAY TWP 56E Operating Parameters

Diameter Amps Volts3.25mm,1/8” 110-140 26-304.0 mm.5/32" 120-160 26-305.0mm.3/16" 160-180 26-30

Diameter Amps Volts3.25mm,1/8” 110-140 26-304.0 mm.5/32" 120-160 26-305.0mm.3/16" 160-180 26-30

TRIMAY TWP 57E Operating Parameters

TRIMAY TWP 61E Operating Parameters

2.4Applications2.4ApplicationsScrew conveyer Bucket teeth Bulldozer corner bits Fan blades Concrete mixer blades Hammer mill impellers Crusher jaws and roll shells

2.5 Advantages2.5 AdvantagesWear resistanceCorrosion ResistanceWear preventionImprove the life of the materialFlexibleLow costLow dilutionVery wide range of hard-facing

materials

3.THERMAL SPRAYING3.THERMAL SPRAYINGThermal spraying techniques are coating processes in which melted (or heated) materials are sprayed onto a surface of base materials.Thermal sprayed coatings are extremely effective at increasing the component life and value, decreasing machinery down-time, and improving performance in a wide variety of applications.

Line Diagram of Thermal Line Diagram of Thermal SprayingSpraying

3.1 Working principle3.1 Working principleThe coating material for thermal spraying included metals, alloys, ceramics, plastics and composites.This materials are feed by the form of powder or wire in the feeder.In this feedstock materials are melted by heating source in the form of molten or semi molten state.And then the material is propelled by process gas and sprayed onto the substrates in the form of micrometer-size particles.Where it is solidifies and form a solid layers.The thickness of thermal spray coating is approximately 20 micrometer to several mm.

Schematic Diagram of Schematic Diagram of therma sprayed coatingstherma sprayed coatings

3.2 Thermal Spray Coating 3.2 Thermal Spray Coating ProcessProcess

Wire Flame SprayPowder Flame SprayElectric Arc Wire SprayHigh Velocity Oxy-Fuel Spray

(HVOF)

3.2.1 Wire Flame Spray3.2.1 Wire Flame Spray

3.2.2 Powder Flame Spray3.2.2 Powder Flame Sprayflame.wmv

3.2.3 Electric Arc Wire 3.2.3 Electric Arc Wire SpraySpray

electric_arc video.wmv

3.2.4 High Velocity Oxy-Fuel 3.2.4 High Velocity Oxy-Fuel SpraySpray HVOF.wmv

3.3 Applications3.3 Applicationso Aircraft Landing Gear Components.o Medical Implantso Textile Machinery Componentso Gas Turbineo Printing Industryo General Industrial Useso Consumer Goodso Automotive Industry o Steel Industryo Paper Industry o Aerospace

Flame spraying with subsequent fusing

Advantages:Metallurgical bondingCan use induction or vacuum furnacesLiquid- and gas-tightHigh Velocity Oxygen Fuel Flame Spraying (HVOF)

Advantages:Very dense coatingsExcellent bondingMinimal metallurgical changesMinimal temperature effects

3.4 ADVANTAGES3.4 ADVANTAGES

Case study: Shoe Component Case study: Shoe Component for Rotary Valvefor Rotary ValveReason to Consider Surfacing

Wear on shoe component of rotary valve results in leakage in the closed position.

IssuesReduce wear to eliminate

material wastage and reduce maintenance costs.

Thermal sprayed rotary-valve shoe component.

Conti..Conti..Benefits

Extends the service life of the shoe by 8 to 10 times that of theuncoated part.

THANK YOUTHANK YOU