EFFECT OF W/C RATIO, ADMIXTURE, SIZE OF AGGREGATE ON COMPRESSIVE STRENGTH OF ...
Vecalloy 700 - Polymet Technical Datasheet
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Vecalloy 700
Technical Datasheet
PRODUCT OVERVIEW
Vecalloy 700 has been specifically designed to
perform in aggressive environments possessing both
abrasive wear and impact. It meets a unique
materials requirement in that it possess the high
abrasion resistance similar to tungsten carbide
based solutions (WC PTA) and high impact toughness
over 500X that of WC PTA.
In order to achieve this goal, computational
metallurgy has been used to create an Fe-based alloy
which inherently grows tungsten boride particles
which are on the order of 100-200X smaller than
the WC particles used in conventionalPTA.
DESIGN APPROACH
The design process for Vecalloy involves a proprietary high throughput computational metallurgical process
to evaluate millions of candidate alloy compositions. Potential candidates are then experimentally evaluated
using an advanced screening process where both propertiesand alloy microstructure are measured.
The combined computational and experimental approach allows us to rapidly design the final material with a
much better accuracy than conventional experiment-based methodologies.
VECALLOY 700 CHEMISTRY AND
PERFORMANCE
Material Chemistry (wt%)
Vecalloy 700
at
2,500X
B C Cr Nb Ti W Other Fe
<4 <4 <30 <10 <10 <20 <10 Bal.
‣ ASTM G65A: 0.08 – 0.12 grams lost
(low stress abrasion)
‣ Jaw Crusher Test: 0.217g lost
(high stress abrasion)
‣ Hardness: 62-65 HRC
‣ Impact Resistance: 0.003-0.01
grams lost (after 3,600 8J Impacts)
Vecalloy 700 has been designed to outperform Tungsten Carbide, Nickel Matrix (WC-Ni) Plasma Transferred Arc
Solutions. The most critical limitation, and thus the property which governs the lifetime of WC-Ni PTA coatings, is
the poor impact resistance or toughness. Vecalloy 700 exhibits an impact resistance over 500 times that of WC-Ni
PTA coatings, while alsomaintaining a similar abrasion resistance.
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Vecalloy 700
Technical Datasheet
WHY VECALLOY 700 OUTPERFORMS WC-Ni PTA
Homogeneity: Unlike a PTA coating which
effectively involves depositing two separate
materials simultaneously, a Ni matrix and WC
particles, Vecalloy 700 is deposited as a single alloy
which naturally grows a network of carbide and
boride fine-scale precipitates.
Whereas WC may sink or float in a molten weld
pool resulting in varied performance through the
thickness of the weld, the Vecalloy 700 carbide and
boride network are thermodynamically driven to
precipitate at equal concentrations throughout the
weld thickness.
Notice in the micrographs on the following page how the WC particles are clumped together in some areas of
the weld and some sections are free of WC particles in the WC-Ni PTA coating. Whereas, the carbide spacing is
thermodynamicallydriven to a very precisespacingin the Vecalloy 700 weld.
Fine-Scale Microstructure: WC PTA coatings typically use carbide particles on the order of 50 to 200 microns in
size.
Notice how large carbides can be seen in the WC PTA micrograph on the following page, but at 500X it is very
difficult to see the carbides in Vecalloy 700. Only in the 2,500X micrograph on the cover page can the
tungsten boridesand carbides in Vecalloy 700 be seen clearly.
Unlike typical WC PTA applications, the carbides a n d
borides in Vecalloy 700 are thermodynamically grown
in the liquid alloy and thus are always consistent
in size, shape and distribution. This fine scale
microstructure has many beneficial effects such as
preventing small sand particles from attacking the
matrix directly, and distributing thermal stresses
more evenly upon cooling.
However, perhaps the most important benefit of
the Vecalloy 700 microstructure is the ability to
withstand impact and high stresses. Almost
every application which is commonly understood to
be an abrasive environment is also an environ
ment containing high stress and significant levels
of impact.
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Vecalloy 700
Technical Datasheet
In the micrograph (right) the WC particles are
clumped together in some areas of the weld and
some sections are free of WC particles in the WC- Ni
PTA coating. Whereas, the carbide spacing is
thermodynamically driven to a very precise
spacingin the Vecalloy 700 weld.
Carbide
Rich
Carbide
Depleted
Notice too, largecracks (highlighted by the
white arrow) running through the
microstructure of the 25X WC PTA coating.
Large carbides can be seen below in the WC PTA
micrograph, but at 500X it is very difficult to see the
carbides in Vecalloy 700.
Only in the 2,500X micrograph on the cover page can
the tungsten borides and carbides in Vecalloy
700 be seen clearly.
Crack
WC PTA
at
25X
WC PTA
at
500X
Vecalloy 700
at
500X
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Vecalloy 700
Technical Datasheet
MaterialLoss(g)
HOW VECALLOY 700 OUTPERFORMS WC-Ni PTA & CHROMIUM CARBIDE
Many people are surprised to see that despite Vecalloy 700 testing at slightly less abrasive resistant than WC PTA
coatings, the Vecalloy 700 significantly outlasts WC PTA in actual application. The answer lies in the revolutionary
improvement in impact resistance.
While WC PTA is well known as the standard for
abrasion resistance under ASTM G65 testing,
relatively low levels of impact can generate
cracks and significant levels of material loss. As
shown in the diagram below when subject to 30
minutes of wear (ASTM G65) all of the coatings
exhibit very minimal material loss. However,
after 30 minutes of impact, the WC coating
exhibits a accelerated levels of material loss.
Therefore, depending on the application, a greater
level of concern should be placed on improving
impact resistance than on abrasion resistance.
How can we define the level of impact that one
should pay attention to? This particular impact test
is standardized to 8J of impact energy, the amount
of energy developed by dropping a 2 lb. rock a
distance of 3ft. It stands to reason that many
more applications should consider the use o f coati
ng solutions with better impact resistance.
Vecalloy 700 has an impact resistance over 500X
that of WC PTA or Chromium Carbide solutions.
Impact and Abrasion Testing Results of Wear Resistant Coatings
15
14
Wear Loss
Impact Loss
11.25
7.5
3.75
0
3.25
1.5 1.75
0.003
WC-NiCrSiBFe WC-NiSiB CrC (High
Carbide)
CrC (Low
Carbide)
Vecalloy
700
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Vecalloy 700
Technical Datasheet
SUGGESTED APPLICATIONS
Vecalloy 700 coatings are suggested for use in any
applications where abrasion resistance is required.
The revolutionary improvement in impact resistance
and toughness will typically result in an extended
lifetime over WC PTA and Chromium Carbide
coatings.
Specific applications include:
‣ Shaker Screens
‣ Grader Blades and other Ground Engaging
Tools
‣ ChuteBlocks
‣ Pipe I.D.
‣ Other Mining Applications
CASE STUDY: SHAKER SCREENS
Vecalloy 700 was run in a side-by-side comparative field trial in the oil sands of Alberta. The Vecalloy
700 screen showed a 3X increase in screen lifetime. The adjacent WC PTA screen required two on-site reapirs
due to spalling of the coating, the Vecalloy 700 did not require any repairs.
This application is a good example of how Vecalloy 700 can be effectively utilized in abrasive
environments which also contain impact to improvecomponentlifetime at reducedcomponentcost.
HOW TO USE VECALLOY 700
Vecalloy 700 is currently available in 1/16”,
3/32”, and 7/64” metal cored wire as well as
53-150µm powder for Plasma Transferred Arc
(PTA) welding or Laser welding. Additional
welding wire diametersareavailableupon request.
The suggested welding parameters and expected
results for Vecalloy 700 are provided on this page and
the following pages.
Vecalloy 700 1/16-inch GMAW WELDING PARAMETERS
WireDiameter 1/16 in (1.6 mm) 1/16 in (1.6 mm)
Current DCEP DCEP
Desired Weld Thickness 3 - 4 mm 6 - 8 mm
Voltage 26 - 29 26 - 29
Amperage 250 - 280 250 - 280
Shielding Gas Ar 100%, Ar 98%/O2 2% Ar 100%, Ar 98%/O2 2%
Stickout 1 - 1.25 in (25 - 32 mm) 1 - 1.25 in (25 - 32 mm)
Preheat 300 - 400F (150 - 200C) 300 - 400F (150 - 200C)
Torch Drag Angle 5 - 15° 5 - 15°
Travel Speed 7 - 15 in/min 3 - 5 in/min
Expected Hardness 62 - 65 HRc 62 - 65 HRc
Expected ASTM G65 mass loss 0.08 - 0.12 g 0.08 - 0.12 g
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Vecalloy 700
Technical Datasheet
HOW TO USE VECALLOY 700 (cont’d)
Vecalloy 700 3/32-inch GMAW WELDING PARAMETERS
WireDiameter 3/32 in (2.4 mm)
Current DCEP
Desired Weld Thickness 6 - 8 mm
Voltage 28 - 30
Amperage 340 - 380
Shielding Gas Ar 100%, Ar 98%/O2 2%
Stickout 1 - 1.25 in (25 - 32 mm)
Preheat 300 - 400F (150 - 200C)
Torch Drag Angle 5 - 15°
Travel Speed 4 - 8 in/min
Expected Hardness 62 - 65 HRc
Expected ASTM G65 mass loss 0.08 - 0.12 g
Vecalloy 700 7/64-inch SUBMERGED AND OPEN ARC WELDING PARAMETERS
WireDiameter 7/64 in (2.8 mm)
Current DCEP
Desired Weld Thickness 6 - 8 mm
Voltage 28 - 30
Amperage 480 - 510
Stickout 1 - 1.5 in (25 - 38 mm)
Preheat 300 - 400F (150 - 200C)
Torch Drag Angle 5 - 15°
Travel Speed 4 - 8 in/min
Expected Hardness 62 - 65 HRc
Expected ASTM G65 mass loss 0.08 - 0.12 g
