Presented by Dean Hooks Thermion Scope This webinar defines thermal spray coating TSC and provides an overview of its inspection Introduction This webinar will review the procedures for the inspection of metallic thermal spray coatings TSCs of aluminum zinc and their alloys and composit ID: 569111
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Slide1Slide2
Inspection of Thermal Spray Coatings
Presented by: Dean Hooks, ThermionSlide3
Scope
This webinar defines thermal spray coating (TSC) and provides an overview of its inspectionSlide4
Introduction
This webinar will review the procedures for the inspection of metallic thermal spray coatings (TSCs) of aluminum, zinc, and their alloys and composites for the corrosion protection of steel
Inspection requirements in accordance with
SSPC-CS 23.00/AWS C2.23/NACE No.12
Slide5
What is Thermal Spray?Slide6
Thermal Spray Coating (TSC) Materials
Aluminum, zinc, and their alloys in the form of powder or wire heated to a plastic or molten stateSlide7
How does TSCs Protect Steel?
Sealed: Good barrier protection
Unsealed: Galvanic (sacrificial) protectionSlide8
Special Properties
Very good resistance to high temperatures, sunlight, and weathering
Good application properties: adhesion to metals, film build, edge retention, and transfer efficiency
Good impact and abrasion resistance
Attacked by acids or alkalis unless
topcoatedSlide9
Environmental Advantages
No volatile organic compounds (VOCs) to cause air pollution (100% solids)
No hazardous air pollutants (HAPs)
Limited overspray into surrounding areasSlide10
Economic Advantages
Long-term protection (40+ years) of steel structures resulting in low life-cycle costs (costs per year)
Reduced rework for original coating defects
Reduced maintenance over coating lifeSlide11
SSPC-CS 23.00/AWS C2.23/NACE No.12
Revised May 2016
A procedure for the application of metallic thermal spray coating (TSCs) of aluminum, zinc, and their alloys and composites for the corrosion protection of steel
Required equipment, application procedures, and in-process quality control (QC) checkpoints are specifiedSlide12
Pre-Surface Preparation Requirements
The steel surface temperature shall be at least 3°C (5°F) above the dew point temperature
Verify compressed air cleanliness in accordance with ASTM D4285
Verify cleanliness of abrasive in accordance with SSPC-AB 1, 2, or 3Slide13
Surface Cleanliness
Before TSC application, steel substrate shall be prepared in accordance with:
SSPC-SP 5/NACE No. 1 for immersion service; or
Minimum of SSPC-SP 10/NACE No. 2 for other service applications; and
Level of nonvisible contamination specifiedSlide14
Surface Profile
Unless otherwise specified:
Minimum angular profile depth of 65μm(2.5 mil)
Maximum angular profile depth of 125μm(5.0 mil)
Measured in accordance with SSPC-PA 17 using ASTM D4417:
Method B
–
Depth Micrometer
Method C
–
Replica TapeSlide15
ASTM D4417 Method B
Depth micrometer
Profile measured using a fine pointed probeSlide16
ASTM D4417 Method C
Replica Tape
A composite tape is impressed into the blast cleaned surface forming a reverse image of the profileSlide17
Job Reference Standard (JRS)
A JRS shall be prepared for each TSC application or product
Intended to be used as a “comparator” to evaluate the application process
TSC thickness and adhesion measurements shall be performed on the JRSSlide18
Inspection of TSC Thickness
TSC thickness measured in accordance with SSPC-PA 2
Coating Thickness Restriction Level 4
Spot readings can be between 80% of the specified minimum and 150% of the specified maximum thickness
Area average must be within specified thicknessSlide19
Thermal Spraying onto Blast Cleaned SteelSlide20
Inspection of TSC Adhesion
TSC adhesion measured in accordance with ASTM D4541 Methods C, D, E, or FSlide21
Thermal Spray System RequirementsSlide22
Nonmandatory Adhesion Testing
Bend Test
180 degree bend on a Mandrel
Qualitative, testing proper surface preparation, equipment setup, and spray parameters
Mandrel diameter for threshold of cracking depends on substrate and coating thicknessSlide23
Bend Test
Passes
On the bend radius, there is no cracking or spalling, or only minor cracking that cannot be lifted from the substrate with a knife blade
Fails
Coating cracks with lifting from the substrateSlide24
Bend TestSlide25
Nonmandatory Adhesion Testing
Hammer and Chisel Cut Test
A procedure to identify areas of metallized coating that are poorly adhering
Involves
impacting the coating with blow from a hammer to a masonry chisel
Any
disbonding
or peel of the coating is considered a failureSlide26
Hammer and Chisel Cut TestSlide27
Hammer and Chisel Cut Test
PassSlide28
Hammer and Chisel Cut Test
FailSlide29
Questions?