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WELCOME ESTEEMED DELEGATES - ESI Africa
Transcript of WELCOME ESTEEMED DELEGATES - ESI Africa
WELCOME ESTEEMED DELEGATES
It is with great appreciation that this workshop is being hosted.
This workshop will empower you to address the ‘Weakest
Link’ found on all Utility infrastructure throughout Africa. This
is a 1st of a kind event, presented by a panel who are
passionate contributors in the field of corrosion.
We are going to share this information with you.
Protect your Critical Assets - HRCSA
Africa’s largest power Utility is leading the way by implementing a specialized joint sealant technology. In collaboration with various Stakeholders, this proven and tested technology protects the “Weakest Link” against Crevice Corrosion.
Utilities depend on structural integrity and longevity of assets with the aim to minimise maintenance.
Crevice corrosion, second to vandalism, is the largest threat that Utilities face.
For new and weathered metal and concrete infrastructure, these speakers, with years of interaction with a variety of Stakeholders, who are all experts in the fields of Metallurgical Science, Industrial Coatings Technologies and Energizing Sub-Sahara-Africa, will provide you with a detailed insight into Crevice Corrosion and how to reduce Crevice Corrosion related maintenance.
“Projects provide new challenges and solutions
through successful interventions”.
Today we are sharing this information with you.
SCOPE OF TODAYS DISCUSSIONS
What is the Weakest Link
Nut & Bolt Corrosion
Protection Methods - Passive Barriers
- Active Seals
Chemistry of HRCSA
Training Requirements
SOLAR ARRAY ASSEMBLIES
USES DIFFERENT
METALS
ALUMINIUM
STAINLESS STEEL
COPPER
GALVANIZED STEEL
CHALLENGE
PHOTOVOLTAIC MODULES
Designed for an operational life span of more than 25 years
in the field.
Entire installation including the fasteners, should target a
similar life span - but
The Fasteners are corroding.
The Fixing Brackets are corroding.
CREVICE CORROSION
FASTENERS
CREVICE CORROSION
THE WEAKEST LINK
The fate of a complex steel assembly may be determined by
the vulnerability of its smallest and least considered
components.
The fasteners holding the assembly together are the areas
where corrosion starts first, where the effects of crevice
corrosion has the most serious consequences.
MOST SERIOUS THREAT TO ASSET OWNERS
WHY DO BOLTS RUST SO EASILY?
In steel bolted systems, large components are assembled and
secured, using relatively small nuts and bolts.
Assemblies are everywhere - Lattice Towers, Substations,
Water Reticulation Systems and other metal infrastructure.
In the joins, Differential Aeration Corrosion is the just one of
the causes – The Greatest Threat.
ALL STRUCTURES MOVE
Pulsation, Vibration & Thermal Fluctuation
Weight Loads, Thermal Fluctuation, Lateral
Deflection (wind)
AT THE FASTENERS WHERE JOINTS ARE CLAMPED
PIPELINES
&
MACHINERY
LATTICE
STRUCTURES
BOLT CORROSION - DIFFERENTIAL AERATION
CORROSION
CROSS-SECTION OF CORRODED NUT & BOLT
NUT & BOLT CORROSION EXPLAINED
BOLT PROTECTION AGAINST CORROSION
HOT DIP GALVANIZING OF FASTENERS FOR
PROTECTION
WHEN HOT DIP GALVANIZING, THREADS OF THE NUT
ARE OVERSIZED TO CREATE SPACE FOR THE ZINC
BY DOING SO THE TENSILE STRENGTH OF THE BOLTS
ARE WEAKEND
LOAD
DISTRIBUTION
The first two
threads hold 57%
of the load
If the first thread
fails, the rest
follow in a domino
effect
TENSILE STRESS VS. SHEAR STRESS
Failure occurs in the threads at the fastener’s weakest
point, made weaker by oversizing.
The amount of tension created in a bolt not only
depends on the strength of its body but on the shear
strength of its threads.
Thread pitch engagement needs to be close to 100%,
to develop the full ultimate strength of the bolt.
CORROSION
“Bimetallic corrosion occurs when 2 metals, with different
potentials, are in electrical contact while immersed in an
electrically conducting liquid. Because the metals have different
natural potentials in a liquid, a current will flow from the anode
(more electronegative metal) to the cathode (more
electropositive metal), which will increase the corrosion on the
anode.” Corrosion Exclusively Vol.2 Issue 2, 2016 p26.
WHAT CAUSES CORROSION?
Moisture (electrolyte – H2O)
Oxygen (O2)
MULTI Metals (fasteners, washers, flanges, welds)
Allowing - CORROSION CELL FORMATION
ATHMOSPHERIC VAPOUR
PLANTS - DEW METAL - CONDENSATE
CORROSION CELL
COMPONENTS:
WATER (H2O)
OXYGEN (O2)
ELECTRON FLOW
(Electric current)
Iron (Fe)
ANCHOR BOLTS & FOUNDATIONS
CONDENSATE RUNDOWN
ANCHOR BOLTS & FOUNDATIONS
ANCHOR BOLTS & FOUNDATIONS
HOW TO PROTECT YOUR ASSETS?
• FASTENERS
• BRACKETS
• EQUIPMENT
COMPONENTS
• MEMBER
INTERFACES
• JOINTS
• ANCHOR BOLTS &
FOUNDATIONS
PROTECTIVE COATINGS
TWO TYPES
PASSIVE
BARRIER
ACTIVE
SEAL
PASSIVE BARRIER COATINGS
PASSIVE
BARRIER
EPOXIES
POLYURETHANES
INORGANIC ZINC COATINGS
POLYSILOXANE (SILICONE)
WEAKNESS HARD & CRACK - ALL STRUCTURES MOVE.
NO CHEMICAL REACTION WITH METAL.
LEADS TO UNDERCREEPAGE.
ARE ALL INERT LAYERS OF COATINGS FORMING A PASSIVE SHELL
PASSIVE
BARRIER
ACTIVE SEAL COATINGS
HOT DIP GALVANIZING
HIGH RATIO CALCIUM
SULFONATE ALKYD
(HRCSA)
ACTIVELY REACTS WITH THE SURFACE OF THE METAL
SUBSTRATE
ACTIVE
SEAL
HOT DIP GALVANIZING
PROVIDES ACTIVE SEAL PROTECTION
Zinc Carbonate Layer (Not easily removed)
CATHODIC PROTECTION – Zinc (ANODE)
is electro-negative to carbon steel
HOW TO MITIGATE CORROSION?
Eliminate the electrolyte
or
Prevent the flow of electrical current
or
Prevent oxidation
or
Modify the environment
HRCSA DOES ALL OF THESE!
Eliminates the corrosion cell (exclude electrolyte)
&
Prevents the flow of electrical current (bad conductor)
&
Prevents oxidation (exclude oxygen)
&
Modifies the environment (raise the pH > 10)
HRCSA: PERFORMANCE BY FORMULATION
HIGH CORROSION RESISTANCE – Due to the
chemical reaction of the mild sulfonic acids in the HRCSA
with the Zinc Carbonate Layer (not easily removed) on the
metal surface of the Zinc - The pH is lifted to pH > 10.1
This modified environment actively mitigates corrosion.
HRCSA COATING: PERFORMANCE BY FORMULATION
HIGH CORROSION RESISTANCE – Due to the
chemical reaction of the mild sulfonic acids in the
HRCSA with the Zinc Carbonate Layer (not easily
removed) on the metal surface of the Zinc
The pH is lifted to pH > 10.1. This modified
environment actively mitigates corrosion.
HRCSA COATING
HIGH RESISTANCE TO UNDER-CREEP - high
affinity of the calcium sulfonate for bare metal resists the
formation of under-creeping
ADHESION BY MEANS OF
VAN-DER-WAALS FORCES –
POS & NEG ATTRACTION
HRCSA COATING
MOISTURE DISPLACEMENT - HRCSA has a higher
affinity for metal than water (hydrophobic).
The Calcite (CaCO3) platelets prevent oxygen and water from reaching the
substrate, eliminating the electrolyte needed for corrosion and oxygen
needed for oxidation
HRCSA RED PENETRANT & TOP COAT
HRCSA IS COMPATIBLE WITH CONCRETE
Uncontrolled steel chemistry explained…
PROBLEM : STEEL CHEMISTRY
HDGASA
“We are confronted with imported steel chemistry that is not always
conducive to a quality hot dip galvanized finished product
Imported steel have shown that the percentage Si and P content is not
controlled, leading to differences in hot dip galvanized steel surface
finishing’s
Uncontrolled steel chemistry has a direct influence on the quality of the
surface finish of hot dip galvanized steel”
Volume 10 Issue 3 2013 Hot Dip Galvanizing Today
KIPTS EVALUATION: DUPLEX & OVERCOAT SYSTEM
Eskom LES requested that the HIGH RATIO
CALCIUM SULFONATE ALKYD (HRCSA) be tested
before any application to steel will be considered.
ESKOM EVALUATIONNov 2013 – Nov 2015
HIGH RATIO CALCIUM SULFONATE ALKYD (HRCSA) AS
AN ACTIVE DUPLEX COATING FOR GALVANIZED STEEL
LOCATION: Koeberg Insulator Pollution Testing Station (KIPTS)
POLUTION LEVEL: CX5+ (ESKOM)
DURATION: 24 MTHS
KIPTS EVALUATION: DUPLEX- & OVERCOAT SYSTEM
TO DETERMINE PRODUCT PERFORMANCE BASED ON
VARIOUS DEGREES OF SURFACE PREPARATION
PROCEDURES DUE TO ON-SITE APPLICATION
KIPTS 2nd HIGHEST POLLUTION ZONE IN THE WORLD
KIPTS EVALUATION
SUBSTRATE PREPARATION PROCEDURES
• No Prep
• Wire brushing & dusting
• Wire brushing & water washing
• Wire brushing, water washing with salt removal
additive
SAMPLES PROVIDED
OLD & NEW GALVANIZED STEEL
SAMPLES MOUNTED
THEN COATED WITH HRCSA
NEW
GALVANIZING
SURFACE
PREP: NONE
8760 HRS
13 Nov 2013 13 Nov 2014
NO CORROSION
OR
UNDERCREEPAGE
27 Months
815 Days
19 560 Hours
NO
UNDERCREEP
OR CORROSION
AT SCRIBE
HRCSA TESTING
MILD STEEL PANEL
GRIT BLASTED TO
NEAR WHITE METAL
FULLY COATED WITH
EPOXY
THEN ½ COATED WITH
HRCSA
EACH HALF SCORED
KIPTS NOV 2013
HRCSA TESTING
NOV 2014(12 months later)
CORROSION &
UNDERCREEPAGE ON EPOXY
(PASSIVE BARRIER)
NO CORROSION OR
UNDERCREEPAGE ON HRCSA
(ACTIVE SEAL)
ENLARGED PIC
NO PROTECTION AT
SCRIBE (EPOXY)
DIRECT CONTACT
WITH ATMOSPHERE
UNDERCREEPAGE
CAUSING
DELAMINATION
AND ACCELERATED
CORROSION
3RD PARTY TESTING IN USA
U.S Army Corps of Engineers
(2 866 hrs)
PowerTech Inc. – Canada
(4 000 hrs)
Kentucky Transport Authority
(5 000 hrs)
Federal Highway Authority
(ALT – 6 840 hrs)
(Marine – 24 month) – Outdoor
Nov 2012
SA SALT FOG TEST RESULTS (ASTM B117) 1 500 HRS
Testing Laboratory: Metlab Germiston (SANAS approved)
RESULTS
The coating showed no defects after
1500h salt fog exposure.
A cross cut scribe was made through
the coating down to the metal
substrate and no under-film creep
occurred at this scribe mark during
the test period.
SA SALT FOG TEST RESULTS (ASTM B117) 1 500 HRS
Discussion of Results
The results showed excellent corrosion protection for the
period tested [1500h].
Rule of thumb - 1000h salt spray exposure test = 3 yrs
marine exposure
HIGH RATIO CALCIUM SULPHONATE ALKYD
Formulated as an overcoat & encapsulating system for
Hot dipped galvanizing
Red lead based coatings
Aluminium-Zinc coatings
Zinc-rich primers & topcoats
Direct to metal (DTM) and concrete
Passive barrier coatings (except silicone, bitumen)
ANTI-CORROSION COATING
I’m now going to hand over to
Gary Watson (President of Watson Coatings Inc.)
and
Rick Noles(Sales Director of Watson Coatings Inc.)
CALCIUM SULFONATE CHEMISTRY
WATSON COATINGS INC.
TYPES OF CALCIUM SULFONATE
• LUBRICANTS & GREASES
• FUEL ADDITIVES
• THICKNERS FOR CONVENTIONAL COATINGS
• CORROSION INHIBITORS FOR CONV. COATINGS
• AVAILABLE IN WATER-BASED AND SOLVENT-BASED
• GELLED OR OVERBASED RESINS
GELLED or OVERBASED RESINS
“WATER-BASED RESINS HAVE NOT PROVEN TO
PROVIDE THE PROTECTION OF SOLVENT-BASED”
• USED AS RESINS IN ACTIVE SEAL COATINGS
MODIFIED WITH ALKYD RESINS AND WAXES
• MODIFICATIONS INCREASE WATER RESISTANCE,
WETTING OF THE SUBSTRATE AND FIRMNESS OF THE
COATING
• MUST HAVE A HIGH RATIO OF CS TO THESE MODIFIERS
TO MAINTAIN MAXIMUM CORROSION RESISTANCE
HRCSA FORMULATION
Coatings both passive and active seals are made up of a combination
of resins, pigments, solvents and additives.
Differences in coatings and their performance are the direct results of
these components and the ratio’s that are used in their
manufacturing
In the case of HRCSA it is the calcium sulfonate resin that provides
the excellent corrosion resistance, water resistance, adhesion to bare
metal and galvanizing
HRCSA TESTED & APPLIED
Applications in the US are as old as 1998 in its current
formulation giving WCI almost 20 years experience
Multiple US DOT’s apply the HRCSA to steel bridges.
By multiple independent testing agencies, departments of
transportation, the US ARMY and actual field applications across the US and more recently by ESKOM in SOUTH AFRICA
CONTACT DETAILS
CONTACT THROUGH:
RUSTOPAK (Pty) Ltd
E-mail: [email protected] or [email protected]
+27 82 789 2582 / +27 87 807 9217
URL: http://www.rustopak.com
TRAINING ON THE HRCSA
I’m going to ask Carl Havemann from Corrosion
Enterprises to explain the training that is needed to
apply the HRCSA to conform with ISO Quality
Management System.
CORROSION ENTERPRISES
PAINT APPLICATOR & SUPERVISOR TRAINING
PRESENTER - CARL HAVEMANN (CEO)
PAINT APPLICATOR TRAINING
MISSION
PROVIDE TRAINING AND UP-LIFTMENT TO THE WORKER
TRAINING TO INCLUDE THEORYAND PRACTICAL
PROVIDE CONSULTING SERVICES
COURSES
COATING APPLICATOR COURSE
SURFACE PREPARATIONBRUSH AND ROLLER APPLICATIONSPRAY PAINTING
PAINTING SUPERVISOR COURSE
Certificate issued on passing the exam
TYPICAL PAINT SUPERVISORS TOPICS
THE SPECIFICATION DOCUMENT AND ITS USE
SAFETY
USE OF PAINT DATA SHEETS
USE OF THE QUALITY CONTROL PLAN (QCP)
USING THE COLOUR STANDARD (SABS 1091)
SURFACE CLEANLINESS TO ISO 8501:1:1988
QUALITY MANAGEMENT DOCUMENTATION
• The PROJECT CONTRACT document
• SAFETY
• The PAINT SPECIFICATION document
• Paint DATA sheets (PDS & MSDS)
• The QUALITY CONTROL PLAN (QCP)
ENVIRONMENTAL CONDITIONS
AIR TEMPERATURE
STEEL SURFACE TEMPERATURE
HUMIDITY
DEW POINT
SUBSTRATE INSPECTION
• Surface Cleanliness (Sa & St)
• Water break-free on galvanizing.
• Dust and Debris(SABS 769)
• Soluble Salts(SABS SM 770)
• Dry Film Thickness(SABS SM 141)
• Adhesion Test (ASTM D3359)
PAINT FAILURES
• Pinholes• Cracking• Flaking• Blistering• Crocodiling• Wrinkling• Chalking• Fisheyeing• Blushing• Not curing or drying
SAFETY : PERSONAL PROTECTION EQUIPMENT PPE
• Overalls
• Safety Shoes
• Eye and face protection
• Hard Hat
• Gloves
• Masks (Gas/Dust)
• Ear Plugs
THANKING YOU FOR YOUR INTEREST IN DRIVING INNOVATION
FORWARD!
YOU ARE WELCOME TO ASK ANY QUESTIONS YOU MAY HAVE…
Contact Details
Rustopak (Pty) Ltd
Tel: +27 82 789 2582 / +27 87 807 9217 / + 27 44 620 2478
URL: http://www.rustopak.com