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SHS 8000 TWAS

Application Process

Twin Wire Arc Spraying (TWAS)

Material Chemistry (wt%)

Chromium	< 22%
Boron	< 5%
Molybdenum	< 5%
Niobium	< 5%
Carbon	< 2%
Manganese	< 1%
Silicon	< 1%
Iron	Balance

Microhardness (HV300)

1064 - 1234 kg/mm²

Microhardness (Average)
Elevated Temperature

1030 kg/mm²	70° F
912 kg/mm²	300° F
620 kg/mm²	600° F
309 kg/mm²	1200° F
117 kg/mm²	1400° F

Wear Resistance

ASTM G65-04 Procedure B

2,000 cycles mass loss

0.15 g

Elevated Temperature Erosion

Using coal fired boiler fly ash for
20 minutes at 30° impact angle (α)
at 1200° F


	Volume loss

	α = 30°

SHS 8000 TWAS	1.50
LMC Armacor™ M	3.05
1018 steel plate	8.47

Bond Strength

ASTM C633-01
0.020 in thick coating

1018 Steel

11,400

psi

Coating Properties

Density (g/cm³)	7.30
Coefficient of Friction	0.316

Thermal Expansion


	Temperature	Slope

	100 - 500° C	8.53

Thermal Conductivity


	Temperature	Slope

	23° C	4.280
	50° C	4.678
	75° C	5.055
	100° C	5.269
	125° C	5.505
	150° C	5.707

Impact Resistance (Toughness)

Drop Impact Testing

No cracking/delamination at 480 in-lbs

Coating Description
SHS 8000 TWAS is a glass forming iron based alloy that forms a nanocomposite comprised of a mixed amorphous and nanoscale microstructure when sprayed as a coating. SHS 8000 features high wear resistance, elevated temperature erosion resistance and a unique high hardness/toughness combination.

Key Performance Characteristics


		Excels in elevated temperature environments where fly ash and bed ash erosion occur

		Superior bond strength without necessity of bond coat

		Maintains hardness at elevated temperature

SHS 8000 coatings exhibit superior bond strength, inherently low porosity, high impact resistance and excellent combinations of corrosion and wear resistance. Superior bond strength values signify that this material has exceptional adhesion and cohesion. This also highlights the material’s extremely low residual stress (even at high thicknesses) inherent in this coating type. The probability of “pull-out” of individual particles during wear, erosion and other service conditions is extremely low. Low coating permeability results in a highly corrosion resistant barrier. Low oxide content contributes to high bond strength due to the very limited presence of internal voids and other defects. These characteristics provide predictable coating performance across a broad variety of service environments. SHS 8000 is especially resistant to elevated temperature oxidation, erosion and corrosion for protecting boiler tubes in coal fired boilers.

Elevated Temperature Erosion Resistance
SHS 8000 offers combinations of corrosion resistance and high hardness in elevated temperature environments where fly ash and bed ash erosion occurs. Based on results from aggressive accelerated elevated temperature erosion tests with highly erosive fly ash from a coal fired boiler at 30° and 90° impact angles, SHS 8000 coatings provide increased lifetime over the leading industry standard protective coating and carbon steel substrate.

Impact Resistance
Impact testing on SHS 8000 coatings was performed using a Gardner Impact testing machine with a 12 lb test weight and 0.5” diameter impact punch dropped from 40” height. As-sprayed and heat-treated (one hour soak at 600° C, water quenched) coatings of 0.020” in thickness were tested. The as-sprayed and heat-treated coatings survived 480 in-lbs impact and demonstrated the ability to deform with the substrate without chipping, cracking or delaminating.

Universal Applicability
When SHS 8000 is sprayed directly onto substrate alloys using conventional twin wire thermal spray equipment and standard substrate preparation practices, and without a bond coat, extremely high bond strength is achieved. In Adhesion/Cohesion ASTM C633-01 Bond Strength Tests, extremely high bond strength is achieved for SHS 8000 coatings on plain carbon steel, far exceeding bond strength of conventional coating materials.