voestalpine Böhler Welding
voestalpine Böhler Welding

Thermal Spraying & PTA

Your best choice for your daily thermal spraying challenges.

Powder flame spraying

Flame spraying is one of a number of thermal coating processes. In powder flame spraying, the spray material, in powder form, is melted with an oxy-fuel gas flame, accelerated towards a component by the combustion gases and sprayed onto the surface of the component.

Metallic, oxide ceramic, carbide and plastic powders can be processed using spray guns specifically designed for those materials. Spray guns that frequently take the form of manual torches, preferably using acetylene as a fuel gas because of its high flame temperature, are chosen for metallic alloys based on nickel, iron or cobalt. The powder particles, which are partially melted by the flame, deform on impact with the surface of the component and are deposited there to form a spray coating with a lamellar structure. The main areas of application for thermal coatings are corrosion protection and wear protection.

Powder flame spraying may be subdivided into cold and hot processes. In cold processes, the powders are only applied by the spray gun, and the spray coating is not subjected to any subsequent thermal treatment. UTP has, accordingly, designated these powders as COLDmelt™. The coatings typically have a porosity between  5 and 15%, depending on the process used.

In hot processes, metal powders of materials known as self-fluxing alloys, based on Ni-B-Si, are employed.

The layer that has been sprayed on is melted by a subsequent thermal treatment. The resulting thermal compaction makes it possible to obtain coatings that are virtually free of pores. Depending on the  application, two processes have emerged for this: simultaneous and subsequent melting.

UTP Maintenance has designated these powders according to the process used.

Rotationally symmetrical parts are frequently coated using a two-stage process (subsequent melting), while a single-stage process (simultaneous melting) is often used for surfaces and edges.

UTP Maintenance offers a high quality range of spraying powders for simultaneous applications. Our long term thermal spraying experience enables us to provide the best tailor-made spraying powders for several industries as well as for distributors.

Powder description

  • Powders for flame spraying with simultaneous melting
  • Self-fluxing alloys
  • Powder types based on NiBSi C+Cr+Co+Cu + tungsten carbides

Powder characteristics

  • Alloyed metal powder (some with hard additives)
  • Round grains (matrix)
  • Smooth surface
  • Gas atomized (except hard material additives)
  • Typical grain size: -106 +20 micron, adjusted to the torch
  • Spraying layer hardness ~ 150 HV up to > 60 HRC

Description

Grain size

Chemical composition

Hardness

Properties and applications

SIMmelt™
NiBas22

-106 +20 µm

NiCuBSi

170-240 HV

Surfacing of grey cast iron, resistance to temperature changes and excellent sea-water resistance

SIMmelt™
NiBas25

-106 +20 µm

NiBSi

205-260 HV

Repair surfacing, high impact resistance, press moulds, bearings, pump vanes

SIMmelt™
NiBas25F

-53 +20 µm

NiBSi

190-260 HV

Good wettability and smooth surfaces; surfacing of cast parts, moulds in the glass industry

SIMmelt™
NiBas30

-106 +20 µm

NiBSi

260-310 HV

Anti-oxidation protection and bond coat in case of hard finishing passes, easy to machine cut; valve cones, gearwheels, bearings, moulds in the glass industry

SIMmelt™
NiBas40

-106 +20 µm

NiCrBSiFe

40 HRC

Good resistance to corrosion and wear even at high operating temperatures; drawing dies, forging dies, tools in the plastics industry, ejector pins

SIMmelt™
NiBas50

-106 +20 µm

NiCrBSiFe

50 HRC

Good resistance to corrosion and wear even at high operating temperatures; hardfacing of valves, valve seats, impellers, guide rollers, pressure rollers

SIMmelt™
NiBas60

-106 +20 µm

NiCrBSiFe

60 HRC

Good resistance to corrosion and wear even at high operating temperatures; pump rings, friction bearing surfaces, knife edges, press moulds, camshafts

SIMmelt™
Cobalt45

-106 +20 µm

CoCrNiWFeSiB

400-460 HV

Resistant to changes in temperature, impact and corrosion; valve seats, knife edges, shears and scissor blades, friction bearings, hot punching tools

SIMmelt™
NiBasW35

-106 +20 µm

NiCrBSiFe+WSC

Matrix
60 HRC

High level of protection against abrasive wear; slicing machine blades, conveyor chains, kneader parts

SIMmelt™
NiBasW55

-106 +20 µm

NiCrCoBSiFe+WSC

Matrix
60 HRC

Highest abrasion resistance; mixer-settler parts and kneaders in the ceramics industry, die drawing tools, chopping blades, scrapers

SIMmelt™
NiBasW60

-106 +20 µm

NiCrBSiFe+WSC

Matrix
60 HRC

Highest abrasion resistance; well suitable for automated spraying processes; separator screws, mixing shovels

UTP Maintenance offers a high quality range of spraying powders for subsequent melting applications. Our long term thermal spraying experience enables us to provide the best tailor-made spraying powders for several industries as well as for distributors.

Powder description

  • Powders for flame spraying and subsequent melting
  • Self fluxing alloys
  • Powders types based NiBSi (+Cr +Co + tungsten carbide)

Powder characteristics

  • Alloyed metal powders (some with hard additives)
  • Round grains (matrix)
  • Smooth surface
  • Gas atomized (except hard material additives)
  • Typical grain size: -125 +45 microns
  • Spray coating hardness ~200 HV to >60 HRC

Description

Grain size

Chemical composition

Hardness

Porperties and applications

SUBmelt™
NiBas40

-125 +36 µm

NiCrBSiFe

40 HRC

Good resistance to corrosion and wear even at high operating temperatures; valve discs, conveyor chains, mixer parts, friction bearings, moulds in the glass industry, feed screws

SUBmelt™ 
NiBas50

-125 +45 µm

NiCrBSiFe

50 HRC

Good resistance to corrosion and wear even at high operating temperatures; gauges, cogs, bearing surfaces, cylinders, guide mechanisms, mixer blades, continuous cast rollers, valve discs, glass industry

SUBmelt™
NiBas56

-125 +45 µm

NiCrBSiFeCuMo

56 HRC

Toughened coatings; valve stems, mixer and stirrer shafts, bearing seats, wearing rings, pump shafts, impellers

SUBmelt™
NiBas60

-125 +45 µm

NiCrBSiFe

60 HRC

Excellent resistance to wear and corrosion, high level of hardness with moderate dynamic compression stress; feed screws, running and sealing surfaces in valves, fittings and bearing seats

SUBmelt™
NiBasW35

-125 +45 µm

NiCrBSiFe+WSC

Matrix
 60 HRC

High abrasion resistance; stirrers, mixer blades, mould edges, extruder screws

SUBmelt™
NiBasW50

-125 +45 µm

NiCrBSiFe+WSC

Matrix
 60 HRC

Highest abrasion resistance; stirrer, mixing shovels, screw shafts,

SUBmelt™
NiBasW60

-125 +45 µm

NiCrBSiFe+WSC

Matrix
 60 HRC

Highest abrasion resistance; stirrer, mixing shovels, screw shafts, for automatic spray processes.

UTP Maintenance offers a high quality range of spraying powders for simultaneous applications. Our long term thermal spraying experience enables us to provide the best tailor-made spraying powders for several industries as well as for distributors.

Powder description

  • Powder for thermal spraying without melting (cold process)
  • Metal alloys, hard alloys, hard material additives, usually with bond layer

Powder characteristics

  • Metal or metal-alloyed (some with hard additives)
  • Round grains (gas atomized)
  • Smooth surface
  • Spattered grain, uniform grain structure, water atomized (except for hard material additives)
  • Typical grain size: -125 +36 microns
  • Spray coating hardness ~23 JHB to >60 HRC

Description

Grain size

Chemical composition

Hardness

Properties and applications

COLDmelt™
Base 17

-106 +36 µm

NiAl

150-190 HV

Bond coat, base powder for initial layer under further coats of wear resistant CrNi- and Cu-alloys

COLDmelt™
Base 20

-106 +45 µm

NiAlMo

170-240 HV

Bond coat, base powder on iron-, copper- and aluminium materials, also “one-step-powder”, possible to apply thick layers, good sliding behaviour

COLDmelt™
Zn

-125 µm

Zn

23 HB

Active corrosion protection on steel under atmospheric stresses

COLDmelt™
Ni37

-106 +36 µm

NiCrBSiFeAl

350-380 HV

Oxidation stability at moderate temperatures, high wear resistance; camshafts, bearings of rollings, cylinder liners, valve stems, hydraulic pistons, sliding ways etc

COLDmelt™
CuAl

-120 +36 µm

CuAl

130 HV

Good sliding and emergency running properties; rollers, bearing journals, slideways

COLDmelt™
NiW15

-125 +20 µm

NiCrBSiFeAl+WSC

Matrix
400 HV

Abrasion resistance for micro-particle surfacings, good oxidation stability; ventilator blades

COLDmelt™
Stainless 18

-106 +36 µm

FeCrNiMo

180 HV

Corrosion resistant coatings; pump sleeves, shafts and parts requiring the characteristics of stainless steel in the chemical and petrochemical industry. Special applications where coats like

COLDmelt™
Fe31

-125 +45 µm

FeCrNi

260-350 HV

Chromium steel alloy with high oxidation stability, good machinability; coating on bearing journals, shafts, piston rods

COLDmelt™
OneStep 16

-106 +45 µm

NiCrAlMoFe

170 HV

“One-step powder”, also bond coat, repair and prophylactic protective coating, resistant to high temperatures; flue boilers, finned tube walls

Plasma powder surfacing (PPS/PTA)

Plasma powder surfacing (PPS), also known as the plasma transferred arc (PTA) process, is a thermal coating process. In contrast with the spraying processes, this method is a welding process and so involves metallurgical bonding of the applied material to the base material.

However, if the parameters are set optimally, the degree to which it blends with the base material can be reduced to a minimum. The PTA process is employed primarily for the surfacing of wear resistant and corrosion resistant coatings onto a base material.

The process is characterised by the use of two separately controllable electric arcs. One of these is the (non-transferred) pilot arc. This arc is formed between the non-melting (tungsten) electrode and the plasma nozzle. It accelerates the plasma gas and enables ignition of the (transferred) main arc. This arc burns with a high energy density between the electrode and the workpiece. With the aid of the electric arc, both the base material and the metal powder that serves as the welding consumable are fused together, which then gives rise to the deposited protective coating. Ar, H2, He, or mixtures of gas are employed as a processing gas. This serves, firstly, as a plasma gas and, secondly, as a shielding gas and as a carrier gas for the powder.

Because of its high degree of automation, the PTA process is clearly most suitable for series parts and offers advantages here with regard to:

  • High reproducibility
  • Low degree of dilution with base material
  • Small concentrated heat-affected zone
  • High surfacing rates possible
  • Alloy multiplicity in powder form
  • Material combinations with hard substances

UTP offers these PTA powders as nickel-based, cobalt-based and iron-based alloys. The powders are designated PLASweld™ in keeping with the process for which they are intended. The grain sizes should be chosen according to the type of system; powder grain sizes between 150 and 210 µm are selected for the standard range of PTA.

Another method of using metal powder as a welding consumable is provided by laser powder surfacing. Here, a laser serves as the source of heat for partially melting the surface of the workpiece and fusing the welding consumable in powder form. The high-energy focus of the laser allows precisely targeted surfacing, which makes it possible to provide wear protection at specific places without negatively affecting (e.g. through a high heat input) the properties of the rest of the component. 

Because the coating thicknesses are usually small and the processing times short for laser powder surfacing, PLASweld™ powder of a finer grain size, typically 45-106 µm, can be used here.

UTP Maintenance offers a high quality range of spraying powders for simultaneous applications. Our long term thermal spraying experience enables us to provide the best tailor-made spraying powders for several industries as well as for distributors.

Powder description

  • Alloyed metal powder (some with hard additives)
  • Round grain, smooth surface, gas atomized (except hard material additives)
  • Typical paricle size: -150 +50 microns or -200 +63 microns
  • Surface hardening of about 180 HV (buffer layers) up to 60 HRC

Cobalt-Base products

Description

Grain size

Chemical composition

Hardness

Properties and applications

PLASweld™
Celsit 706

-150 +50 µm*

CoCrWC

41 HRC

Qualities to protect against adhesive and abrasive wear, high-temperature resistant; hardsurfacing of running and sealing surfaces in valves carrying gas, water and acid, hot-working tools subject to high stresses, valve seats, valve collets for combustion engines, grinding, mixing, carrying and drilling tools, dies and press moulds

PLASweld™
Celsit 706HC

-150 +50 µm*

CoCrWC

43 HRC

PLASweld™
Celsit 708

-150 +50 µm*

CoCrNiWC

45 HRC

PLASweld™
Celsit 712

-150 +50 µm*

CoCrWC

48 HRC

PLASweld™
Celsit 712HC

-150 +50 µm*

CoCrWC

49 HRC

PLASweld™
Celsit 721

-150 +50 µm*

CoCrMoNiC

32 HRC

High corrosion resistance and resistance to adhesive (metal-to-metal) wear, buffer material for hard stellite qualities; medical engineering

* Also available in grain size -200 +63 µm or according to customers requirements

Ferrum-Base products

Description

Grain size

Chemical composition

Hardness

Properties and applications

PLASweld™
 Ledurit 60

-150 +50 µm*

FeCrC

57 HRC

Highly wear-resistant, preferred for protection against mineral wear with low impact; feed screws, excavator teeth

PLASweld™
Ledurit 68

-150 +50 µm*

FeCrCBV

62 HRC

Hardfacing on parts with extremely high rubbing wear; grinding rolls, screw conveyor, excavator parts.

PLASweld™
Ferro55

-150 +50 µm*

FeCrMo

55 HRC

Ferreous based alloy combining high strength, toughness and temperature resistance up to 550°C. Applicable on hot and cold work steels.
Cutting tools, forging tools, rollers, mandrels. Powders also available for laser welding with finer grain size (e.g. 45-106 µm)

PLASweld™
Ferro45

-150 +50 µm*

FeCrMo

45 HRC

 

PLASweld™
Ferro39

-150 +50 µm*

FeCrMo

39 HRC

 

PLASweld™
FerroV10

-150 +50 µm*

FeCrV

60 HRC

Ferreous based powder with vanadium carbides, well balanced combination of abrasion resistance and toughness; industry knives, tools

PLASweld™
FerroV12

-150 +50 µm*

FeCrV

61 HRC

Ferreous alloy with finely distributed vanadium carbides in a martensitic matrix. High resistance against abrasion. Hardfacing on highly loaded edges

PLASweld™
FerroV15

-150 +50 µm*

FeCrV

61 HRC

Martensitic alloy with high vanadium and chromium content against a combination of wear and corrosion. Cutting tools, scraper

* Also available in grain size -200 +63 µm or according to customers requirements

Nickel-Base products

Description

Grain size

Chemical composition

Hardness

Properties and applications

PLASweld™
NiBasW60

-150 +50 µm*

NiBSi+WSC

Matrix
 60 HRC

Specially developed nickel-base matrix for highest abrasion stresses, rolling and mineral wear, sliding abrasion, impact demand applications. For excavator parts, drilling tools, screws in the plastic industry and mining

PLASweld™
NiBas 776

-150 +50 µm*

NiCrMoW

170 HB

Corrosion and high-temperature resistant coatings, forging hammers, saddles, continuous cast rollers/ buffer layer, mixer blades

PLASweld™
NiBas 68HH

-150 +50 µm*

NiCrFeNb

170 HB

Buffer layer preferred for stellite qualities, corrosion-resistant; pressure vessel construction, petrochemical industry, power plants

PLASweld™
NiBas 222Mo

-150 +50 µm*

NiCrMoNb

200 HB

Nickel-base  powder for cladding, similar corrosion and temperature resistant  alloys and for surfacing on mild steels. Chemical and petrochemical industries and for repair purposes (valve cladding in ship engines).

* Also available in grain size -200 +63 µm or according to customers requirements

Arc spraying with flux-cored wire process

UTP Maintenance offers a high quality range of powders for plasma transfer applications. Our long term plasma transfer experience enables us to provide the best tailor-made powders for several industries as well as for distributors.

Arc Spraying is the highest productivity thermal spraying process. A DC electric arc is struck between two continuous consumable wire electrodes that form the spray material. Compressed gas (usually air) atomizes the molten spray material into fine droplets and propels them towards the substrate. The process is simple to operate and can be used either manually or in an automated manner.

Product name

Alloy Type

Low stress abrasion

High stress abrasion

Corrosion

Heat

SK 235-M

High alloyed steels

 

x

x

 

SK 255-M

High alloyed steels

 

x

   

SK 420-M

High alloyed steels

   

x

 

SK 848-M

High alloyed steels

   

x

x

SK 825-M

Nickel alloys

   

x

x

SK 830-MF

Nickel alloys

x

 

x

x

SK 840-MF

Nickel alloys

   

x

 

SK 850-MF

Nickel alloys

   

x

x

SK 858-M

Nickel alloys

   

x

x

SK 860-MF

Nickel alloys

 

x

x

x

SK 868-M

Nickel alloys

   

x

x

SK 9000-MF

Nickel alloys

 

x

x

x