A brief summary of selected specialty hardfacing works of mine conducted between 2008 and 2012.

1. Advanced Weld Overlay Solutions
State-of-the-art Hardfacing for Critical Mechanical Components
Guy Chouinard, M.Sc., Eng.
Revision 02 - 2012

2. Modern Weld Overlay Technologies
Limitations of Common Hardfacing Techniques
Welding usually involves considerable heat input and
base metal dilution, often leading to metallurgy issues
and distortion of the substrate.
Conventional hardfacing techniques do not allow for
precise thickness control under 1/8’’ (3 mm) and
typically lead to high finishing costs.
Well-known techniques such as stick electrodes (SMAW)
and MIG (GMAW/FCAW/MCAW) often cause high reject
rates due to overlay defects.

3. Modern Weld Overlay Technologies
Self-Regulated Short-Circuit MIG Process (Rapid Arc)
Molten Metal Transfer Modes
MIG Weld Overlay Process
Conventional MIG Rapid Arc Process
Spray transfer mode SRSC mode

4. Modern Weld Overlay Technologies
Self-Regulated Short-Circuit MIG Process (Rapid Arc)
Higher cooling rate for easier position welding, a finer
metallurgical structure and higher hardness for a given
material, as well as more bead profile control.
Minimum heat input for avoiding dissolution of hard phases,
reducing the base metal dilution rate (3-5%), and lowering
the work piece distortion levels.
Most stable arc and metal transfer because of a self-
regulated balance of inductance and capacitor discharge.
Improved productivity. Less welding defects.

5. Modern Weld Overlay Technologies
Self-Regulated Short-Circuit MIG Process (Rapid Arc)
10X
Typical tungsten carbide nickel bead
200X

6. Modern Weld Overlay Technologies
Better Control of Heat Input and Heat-Affected Zone
High-carbon steel railway bearing box Gray iron pump plate and impeller
Machinable carbon steel build-up Nickel-iron build-up and hardfacing
HEAT-SENSITIVE BUILD-UP WORKS AND CAST IRON REPAIRS

7. Modern Weld Overlay Technologies
Improved Deposition Rate and Cost-Effectiveness
Steel mill furnace table feed rolls Aggregate crusher blow bars
COMBINED IMPACT AND HIGH-STRESS WEAR
WKP-1600-TC TiC-enhanced martensitic steel

8. Modern Weld Overlay Technologies
Reduction of Common Weld Defects Occurence
Extruder valve stem – Stellite® 6

9. Modern Weld Overlay Technologies
Lower Dilution Rate and Enhanced Material Properties
Steel making continuous casting roller
Nitrogen-enhanced advanced stainless steel

10. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)
0.040’’ (1.0 mm) to 0.160’’ (4.0 mm) per weld pass

11. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)
Significant improvements over original design introduced
by Deloro-Stellite in 1962 and commercialized thereafter.
Competes with laser cladding in terms of precision,
repeatability and metallurgies - Introduction of inverters
(pulsed current) and robotics.
Also capable of relatively high deposition rates (10 kg/h)
with lower amperage and consumable cost than ever -
Improvement of torch design.
Possibility of conducting hardfacing works in an inert gas
positive pressure container, mostly for applying titanium
and refractory metal overlays.

12. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)

13. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)

14. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)

15. Modern Weld Overlay Technologies
Enhanced Plasma Transferred Arc Process (ePTA)
Internal composite hardfacing capabilities
Starting at 4’’ (100 mm) inner diameter

16. Advanced Materials Strategy
Wear-Resistant Materials – Self-fluxing Nickel Alloys
CEMA screw coupling shafts
60-HRC NiCrSiB ePTA hard coating
Slurry control valve ball and stem
50-HRC NiCrSiB ePTA hard coating

17. Advanced Materials Strategy
Wear-Resistant Materials – Cobalt-based Alloys
ASTM A-182 F9 alloy steel 30-in ball valve seats
Stellite® 21 and Stellite® 6 dual ePTA hardfacing
Iron content below 5% - ASME Code Section IX

18. Advanced Materials Strategy
Wear-Resistant Materials – Chromium Carbide Irons
WKP-1055 ePTA hardfacing
100 X 500X 53-55 Rockwell C
500X
Advantages of ePTA chromium carbide hardfacing over FCAW:
Random carbide precipitation at ~100 m above interface - Harder microstructure
Typical base metal dilution zone is ~500 m thick - First layer with full hardness

19. Advanced Materials Strategy
Wear-Resistant Materials – Chromium Carbide Irons
WKP-1058 ePTA hardfacing
56-58 Rockwell C
WKP-1068 ePTA hardfacing
66-68 Rockwell C

20. Advanced Materials Strategy
Wear-Resistant Materials – Tungsten Carbide Composites
Typical ePTA tungsten carbide nickel hardfacing
Rolling mill conveyor roll
WK-0600S ePTA tungsten carbide nickel

21. Advanced Materials Strategy
Wear-Resistant Materials – Tungsten Carbide Composites
Anode paste continuous mixers
Tungsten carbide nickel hardfacing

22. Advanced Materials Strategy
Wear-Resistant Materials – Tungsten Carbide Composites
Silicium metal crusher feed rolls
WK-0601A tungsten carbide nickel
Iron ore green pellets crusher rolls
WK-0600S ePTA tungsten carbide nickel

23. Advanced Materials Strategy
Wear-Resistant Materials – Tungsten Carbide Composites
TiO2 pigment dry pump screw and sleeves
WK-0600S ePTA tungsten carbide nickel

24. Advanced Materials Strategy
Wear-Resistant Materials – Tungsten Carbide Composites
Copper smelting converter injection tuyeres
(43 mm ID x 60 mm OD x 1200 mm – 20-40 tph)
WK-0600S ePTA internal hard coating

25. Turnkey Project Solutions
Hard Materials Engineering and Processing

26. Turnkey Project Solutions
Hard Materials Engineering and Processing
Backfill sludge pump wear plates and rings
WK-0600S ePTA tungsten carbide nickel

27. Turnkey Project Solutions
Process Equipment Re-manufacturing
Thick-stock pump rotor segments
Stellite® 6 perimeter repair
Wood chip plug screw feeder
45-HRC self-fluxing nickel alloy

28. Turnkey Project Solutions
Custom Chromium Carbide Wear Plates
WKP-1055 chromium carbide wear plates
55-59 Rockwell C
Iron ore sintering exhaust fan casing

29. Turnkey Project Solutions
Custom Overlaid Slurry Pipes and Fittings
Concentrator slurry pump discharge reducers
WK-0601A ePTA tungsten carbide nickel

30. Turnkey Project Solutions
Tungsten Carbide Nickel Arc Spray Coatings
Iron ore exhaust fan inlet bell