Category Archives: Anodes

Cathodic Protection Connections: Exothermic Welding vs Pin Brazing


Exothermic welding and pin brazing are two methods to connect a cathodic protection system to the protected steel structure. These connections route back to the rectifier to complete the circuit for an impressed current cathodic protection system. Or they connect to the anode lead cable in a galvanic anode system. They are an essential part of any cathodic protection system.

Exothermic welding and pin brazing cathodic protection connections resulted from historical needs in the railroad industry. In addition, both have a long history of use in the cathodic protection industry.

MATCOR has the experience and capability to use either connection technology depending on the client’s specifications or requirements. In the absence of a customer preference, MATCOR generally defaults to pin brazing for CP applications.

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Exothermic Welding for CP

The older of the two technologies is Exothermic or Thermite welding. More prevalent in United States specifications, this technology utilizes the heat generated from the reaction when you ignite a mixture of Aluminum powder and Iron Oxide III (ferric oxide Fe2O3). The resulting reaction is vigorously exothermic, generating temperatures more than 2000 C – sufficient to create molten iron.

Initially developed by German Chemist Hans Goldschmidt in 1893, exothermic welding connected steel rails on the Essen train line. In the 1930s, the technology gained widespread use for connecting bonding cables to railroad ties. This was thanks to the efforts of Charles Cadwell, a physicist for the Electric Railroad Improvement Corporation (ERICO.)

The Cadweld connection process has changed very little over time. It involves cleaning the structure surface down to the bare metal and laying the connector attached to the structure in a graphite mold. Next, you place an appropriately sized cartridge containing the aluminum powder and ferric oxide ready for igniting in the mold. Finally, using an ignitor sparks the reaction. As a result, an iron slug melts and flows over the copper conductor, welding it to the steel surface.

Cathodic Protection Connections: Exothermic Welding vs Pin Brazing

Pin Brazing for CP

Like exothermic welding, the railroad industry developed the second standard cable-to-structure technology—pin brazing.

In Sweden in the 1950s, high heat from thermite welding caused grain growth in the copper cable. As a result, connections to the rails were subject to fatigue failures from cyclical stresses associated with the movement of the rails as trains passed.

To solve this issue, the railroad industry developed lower-temperature joining technology using brazing. Brazing uses a range of silver-based filler metals to achieve the bond. These filler metals have a melting temperature between 620 and 970 C – well below the temperatures reached during exothermic welding.

Commonly specified in European standards, the pin brazing process has remained fundamentally the same since the 1950s, with some refinements to the equipment.

The pre-assembled welding pin and the pin brazing gun are the keys to pin brazing. The pin consists of a stud with a defined amount of flux encapsulated in the brazing metal. When you press the trigger, current flows through the pistol via the pin to the steel pipe. At the same time, an electromagnet is energized, drawing the pin holder and pin away from the steel surface, forming an electric arc. The arc heats the steel and starts to melt the tip of the pin. As a result, it causes the flux to melt and flow onto the steel. The electromagnet de-energizes when the current flow ceases, and the spring forces the molten stud onto the fluxed pipe surface. With the arcing stops, solidification is very rapid.

Comparing Exothermic Welding and Pin Brazing for Cathodic Protection Connections

Safety

Both methods are safe procedures when trained personnel follow the correct procedures. Neither method poses any environmental threat, although users should be sure to properly store and handle the thermite powder charges. For thermite welding, the process can be sensitive to moisture which could vaporize on contact with the molten iron slug. As a result, the potentially dangerous hot metal can be spat out of the mold. For this reason, you should conduct the pin-brazing process in damp environments and offshore applications.

Cathodic Protection Connection Reliability

Both connections have been used extensively and are widely accepted in cathodic protection. Unfortunately, no published data detailing the reliability of either connection technology exists, and reports of Cathodic Protection connection failures are infrequent and anecdotal. Lab testing on tensile load indicates that pin brazing is a slightly stronger bond; however, the loads at failure far exceeded any load possible in regular service. Nevertheless, both techniques will provide reliable, low-resistance connections when properly performed.

Metallurgical Effects

Both processes are thermal and will affect the metallurgical condition of the pipe. Many piping codes typically advise that the design consider the impact of any changes in the parent metal due to localized heating during the attachment process. Microhardness testing has shown that both connections are safe for the normal range of carbon steel pipe; however, some consideration must be given to thin-walled structures. Pin brazing results in lower temperatures and greater process control and should be considered for all thin-walled steel and alloyed piping.

Effects of Cathodic Protection Connections on Internal Coating and Fluids

Using thermal bonding to the exterior pipeline wall of a pipeline filled with highly flammable hydrocarbons requires some consideration. In addition, where internal coatings exist, it is reasonable to question whether or not thermite welding or pin brazing might damage the interior coating. Based on testing, the inner wall temperature rises more with thermite welding than with pin brazing; however, neither method’s results were sufficient to give any reason for concern.

If you need assistance with a cathodic protection assessment, please contact us. We will respond by phone or email within 24 hours. For immediate assistance, please call +1-215-348-2974.

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At What Distance Does Cathodic Protection Continue to be Effective?

This article explores the answer to a question posed by a student about the length of pipeline protected by a cathodic protection system.


What length of pipeline is protected by a cathodic protection system?

We recently received a question from our website from someone who self-identified as a Student. We love when people ask technical questions and are pleased that students visit the MATCOR website–we have always strived to have a content-rich website to help share CP knowledge. The question is as follows:

“For installed impressed current CP systems with 15 anodes, what would be the approximate radius/length of a 200-mile petroleum metal pipe that would be protected?”

So before diving into the answer, let’s frame this question with an assumption, identify some unknowns and provide a definition.

Assumption

The 15 anodes are part of a single anode bed. The anodes are electrically remote from the pipeline and connect to an appropriately-sized DC power supply (transformer/rectifier, solar power/battery unit, thermoelectric generator, etc.)

Unknown #1: Pipeline Details

Before doing any detailed engineering, there are a few details that must be specified:

  • Pipeline diameter and material of construction
  • Coating type and condition
    • The layout of the pipeline (location of pumping stations, valve stations, and metering stations)

Unknown #2: Soil Conditions

Understanding soil resistivity in terms of location, frequency, and spacing, is critical when designing cathodic protection systems for long-length pipelines.

Definition of Attenuation

a lessening in amount, force, magnitude, or value according to Merriam-Webster

When discussing at what distance cathodic protection continues to be effective along a pipeline, you must consider the attenuation of the CP current. At some point, the current diminishes along the length of the pipeline, becomes insufficient, and can no longer protect the pipeline.

The Answer: Impressed Current CP Systems are Complicated

We can effectively use attenuation calculations for signals generated on a uniform conductor and transmitted through a uniform environment.

In this case, the pipeline is not a uniform conductor; unless it is bare, it is anything but uniform. The coating has less than perfect effectiveness and an unknown number of defects distributed in an unknown manner. The environment is equally non-uniform; soil resistivities change based on location and weather changes. The more non-uniformity, the more inaccurate the results will be for any attenuation calculations.

It is virtually impossible to model mathematically for older pipelines with insufficient coatings. The only effective strategy is to collect data by installing a temporary current source to measure the effective current throw in each direction in multiple locations along the pipeline.

For new pipelines with very good coatings, it is possible to perform some attenuation calculations and empirically determine a reasonable separation distance between anode stations.

The math starts with determining something called the propagation or attenuation constant. To calculate this, take the square root of the resistance per unit length of the structure divided by the leakage conductance per unit length.

In Simple Words…

How hard is it for the current to travel along the pipeline versus how easy it is for the current to jump onto the pipeline?

The smaller this number, the further current will spread. Key factors affecting the attenuation constant include earth resistivity (higher resistivity soils mean further current spread) and coating quality (better coating means further current spread). Armed with this, there are six simultaneous equations that we can use, and that include hyperbolic sine and cosine functions.

Larger, new construction pipeline projects require you to consult with a professional engineer. A brief newsletter article will not adequately cover the mathematical gymnastics involved. We did say that the math is complex.

Well-coated, newer pipelines in moderate to high-resistivity soils can typically be protected for 20+ miles in each direction from an anode bed. Poorly-coated or bare pipelines in low-resistivity soils may require anodes every quarter mile or less.


Need more information? Please contact us at the link below.

Three Ton Sled Anode Assemblies Head to Beaumont, Texas

MATCOR shipped four of the heaviest customer sled anodes we have ever fabricated this month – over three tons each. Headed to Beaumont, TX, the anodes are part of a Gulf Coast refinery expansion project. The anodes will protect a variety of marine piling structures as part of a light crude processing expansion at the refinery.

Sled Anode assembly – pouring the concrete bases.

Each anode is rated for 75 amps and weighs approximately 6300 pounds. Each anode assembly consists of a pair of two-inch diameter Mixed Metal Oxide coated titanium tubular anodes, five-foot-long. The anodes utilize MATCOR’s proprietary tubular anode connection technology for larger diameter anode tubes. Each sled anode has two concrete bases resting on a common wood base fabricated with stout 6” x 6” pressure-treated wooden beams. The concrete ends include lifting lugs to support installation by crane either from land or on a work boat. The function of the treated wood beams is to sink into the sea floor.

Completed Sled Anode assembly – waiting on the concrete to cure.

The anode lead cables are dual insulated HMWPE/ Kynar 1/0 cables housed in a proprietary HDPE jacket and held in place along the sea floor using concrete weights.

Sled Anodes are an exceptionally cost-effective means of protecting large near-shore structures such as dolphins, jetties, pilings, and sheet pile walls. They are easy to install and even easy to remove in advance of dredging operations.

More Information About MATCOR’s Sled Anode Products

Marine Anode Sled Product Page

Houston Sled Anode Installation

[YouTube Video] MATCOR Sea-Bottom™ Marine Anode Sled

[Materials Performance Case Study] Impressed Current Anode Systems for Jetty Piling


Need information or a quote for MATCOR custom sled anodes? Please contact us at the link below.

MATCOR Successfully Completes Tank CP Project In Mexico

JA Electronics explosion-proof rectifiers for tank CP project in Mexico.

MATCOR recently completed a significant tank CP project in the Mexican port city of Altamira along the Gulf of Mexico. The project consisted of design, detailed engineering, supplying materials, providing installation supervision, and commissioning and testing the systems upon completion of the installation for nine above-ground storage tanks.

Tank CP Project Utilizes Linear Anodes

The cathodic protection system utilized MATCOR’s SPL Linear Anode Concentric Ring tank system that consists of individual, factory assembled, and tested anode segments. This approach facilitates a simple installation that does not require cutting, splicing, or joining anode assemblies in the field. The anode rings utilize a redundant anode cable feed system that assures reliability. This cost-effective solution protects the bottom of tanks on projects across the United States and around the globe.

Explosion Proof Rectifiers

MATCOR also supplied customized explosion-proof oil-cooled rectifiers (pictured above) for each of these tanks from our sister company, JA Electronics. These rectifiers are used in Class 1 Div 2 hazardous areas. Additionally, cast aluminum Class 1 Div 2 junction boxes were also manufactured and supplied by JA Electronics.


Click below to get a quote for your tank CP project, or learn more about MATCOR’s cathodic protection solutions.

Preventing Corrosion of Near Shore Structures

Rusty Talks about the MATCOR PW® anode, which protects near shore structures in water from the effects of corrosion…

“It’s summertime and our thoughts go to water—backyard swimming pools, kayaking along rivers, boating on lakes, and lounging around the ocean.

Well, here at MATCOR, when we think water, we think about the very versatile MATCOR PW® ANODE system.

Check out some details below and contact our team for assistance.” — RUSTY

Corrosion Prevention of Structures in Water

The MATCOR PW Anode is ideal for corrosion protection of docks, piers, pilings and more.

The PW anode is a lightweight, long life anode system that can be installed to protect a wide range of near shore marine structures from corrosion, including:

  • Docks
  • Piers
  • Jetties
  • Sheet pile walls
  • Wind turbine jackets and monopiles
  • Stationary floating vessels such as riverboat casinos and historic naval vessels

The PW anode system consists of a custom fabricated PVC anode housing and a MATCOR Mixed Metal Oxide anode assembly.

The PW Anode can be supplied with a lowering rope, eye bolt assembly, and optional weight assembly for hanging.

This versatile anode is available in a wide range of sizes and current outputs or can be custom designed for a specific application’s requirements.


To get in touch with our team of corrosion experts for more information, to ask a question or get a quote, please click below. We will respond by phone or email within 24 hours. For immediate assistance, please call +1-215-348-2974.

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Navigating Cathodic Protection Supply Chain Issues

June 2022 Update

MATCOR has historically stocked and specified dual insulated HMWPE/Kynar™ for all of our chemically aggressive cable applications. Many other suppliers in our industry utilize HMWPE/Halar™ for their chemically aggressive cable applications. The two are generally seen as being equivalent materials for cathodic protection purposes.

Due to recent supply chain disruption, MATCOR has had to provide HMWPE/Halar™ in place of HMWPE/Kynar™. This is due to the availability of materials.

Unless explicitly instructed otherwise, MATCOR reserves the right to substitute these two cable installations interchangeably based on material availability.

Should you have any questions, please contact your MATCOR sales representative.

May 2021 Cathodic Protection Supply Chain Update

Historically, MATCOR has enjoyed an exceptional on-time delivery record. Over the past decade our lead times for anodes have gone down. 1-2 weeks for rush orders is quite achievable. 3-4 week deliveries are the norm for MATCOR manufactured cathodic protection products. Through 2020, we were able to navigate cathodic protection supply chain issues and avoid delays due to material availability.

However, if you are reading the news, you cannot help but see stories the stories:

The general state of the global economy is one of delay and disruption accompanied by price increases and surcharges.

In our cathodic protection manufacturing business, we have not been immune to these pressures. Supply is tighter and orders delayed for key items we use on a regular basis. This includes lumber for anode reels to Iridium for our mixed metal oxide anode coatings. Cathodic protection cable availability, especially for Kynar dual insulated cable, has gone from 4-6 weeks to 15+ weeks.

Shipping Issues

The cost and reliability of shipping channels is another challenge facing manufacturers. Both ocean freight and motor freight are struggling with shortages of containers, truck drivers, port congestion and rising fuel costs. Getting materials to our manufacturing facility and shipping them out is more difficult and less reliable than ever before.

At MATCOR, we have a great logistics team and a very flexible manufacturing team. Our on-time delivery record has suffered, but we are doing everything we can to minimize the impact on customers. We communicate early and often with those affected to advise them of any supply delays.

We encourage our customers to give themselves additional lead time by purchasing materials a little earlier than normal. This will assure that they have them on site well in advance of their planned installation. Engage early with MATCOR and your other suppliers to coordinate delivery timeframes. This is a good idea for both planned projects and critical timeline projects as we navigate these challenging times.

More about How Today’s Supply Chain Issues Affect Our Industry.


Don’t allow cathodic protection supply chain issues to affect your project. Plan ahead by contacting us at the link below. For immediate assistance, please call +1-215-348-2974.

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Impressed Current Sled Anodes for Marine Structures – FAQs

Impressed current sled anodes to prevent corrosion of near shore marine structures such as docs, piers and jetties.
Impressed Current Sled Anode for Marine Structures

MATCOR is a leading manufacturer of impressed current sled anode systems and as such we tend to get asked a lot of questions about sled anodes.  Here are some frequently asked questions:

Does it matter whether sled anodes are to be installed in seawater, brackish water or freshwater?  What if the water salinity varies with the season or with tidal action?

These are two related questions, and both have to do with the conductivity (or resistivity which is merely the inverse of conductivity) of the water where the anodes will be located.  The conductivity of the water plays a critical role in determining the overall system resistance and current output of the system.  For freshwater locations, the relatively low water conductivity requires a significant quantity of anodes to keep the overall system resistance down.  In those instances, a sled anode may not be the best design option as sled anodes are most cost effective in brackish or saltwater environments. For environments where the conductivity can vary seasonally or with the tides, such as estuaries or tidal river boundaries, special consideration may be required such as constant current or auto-potential controlled power supplies.

Why would we use impressed current sled anodes as opposed to galvanic anodes? 

Depending on the application, there are compelling reasons for the use of each type of system. Galvanic anodes do not require an external power supply, are less subject to interference issues, and can be closely coupled directly to the structure. The impressed current sled anodes can greatly simplify installation, reduce overall costs, typically have a longer life, and can produce a lot more current from a lot fewer anodes. The choice of anode type is very much a site-specific consideration requiring a proper engineering evaluation during the design phase.

Are there any specific concerns with marine wildlife when evaluating cathodic protection systems?

Marine wildlife is generally unaffected by the presence of a cathodic protection system. Cathodic protection systems have been used in commercial aquariums and fish hatcheries without any impact on the marine life. At the structure, cathodic protection can result in a localized environment that reduces or inhibits the growth of barnacles while changes in the pH at the structure’s surface encourage the growth of calcareous deposits which reduce the current requirements and provide a form of protective coating for the steel structure.

The MATCOR sled anodes utilize a wooden base – are there any concerns with the deterioration of the wooden base releasing in chunks of wood that could damage intake structures?

We have not experienced any such problems – the wooden base is designed to sink into the mud along the sea floor and provide an anchor.  Wood holds up very well in this environment; however, over time the wood will slowly become food for cellulose processing bacteria and eventually will slowly be degraded. This process is a natural process and occurs over a long period of time.  There is no expectation that the wood base would break into pieces that could damage an intake structure. MATCOR can provide an inert non-metallic plastic base that would be like wood but not subject to natural biodegradation.

How do you protect the cabling from the Sled Anode back to the system rectifier?

MATCOR utilizes an HMWPE cable that has a very robust exterior jacket that is suitable for direct burial in soil or water environments. The cable is housed inside a 1” diameter flexible drilled PE pipe that provides mechanical protection for the cabling. We recommend the use of concrete weights to secure the cable along the seafloor. The drilled PE pipe holes facilitate the cabling sinking into the seafloor mud providing additional protection for the cabling.

What about dredging operations?

For locations that are subject to occasional periodic dredging operations every few years or so, MATCOR can provide a locator float and lifting lugs to allow for the anodes to be removed prior to dredging operations. If the frequency of the dredging operations is such that this would be a regular occurrence (multiple times per year), then consideration should be given to alternate designs that would not require anode removal on regular basis.


For information on MATCOR’s Sea-Bottom Marine Anode Sleds or for assistance with marine near shore cathodic protection system design, please contact us at the link below.

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Have Extra 2019 Budget Monies?

MATCOR can help.

This is the time of year when thoughts turn to Thanksgiving and Christmas vacations, using up all your remaining vacation and wondering what to do with any leftover 2019 cathodic protection budget monies.  More than likely, it is too late to schedule and complete new projects.  MATCOR along with most of our competitors have full construction schedules and adding additional commitments is quite difficult.

So what to do with that leftover budget monies that may reset in 2020?  Many of our clients look to stock up on materials for their anticipated 2020 projects.  It is not too late get MATCOR’s Mitigator® Engineered AC Mitigation System, SPL™ Impressed Current Linear Anodes, Durammo® Deep Anode System, MMP™ Prepackaged MMO Canister Anodes and other ancillary materials into this year’s budget.

Click HERE to get in touch with your MATCOR account manager for more information, to ask a question or get a quote. Or, complete our contact form at the link below and we will respond by phone or email within 24 hours. For immediate assistance, please call +1-215-348-2974.

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Helium Leak Testing for Cathodic Protection Anodes

MATCOR is pleased to announce that we are now capable of performing Helium leak testing on our full range of linear anode products as an optional testing service. This is a common practice among companies and product developers that provide products that could potentially leak gas or that require water tightness. Products commonly leak tested include refrigeration lines, vehicle brake lines, and devices that contain potentially harmful or deadly substances. Helium is the second smallest element (Hydrogen is the smallest), which means that it is valuable for leak testing. Smaller molecules naturally can find smaller gaps or defects from which to leak. Unlike hydrogen, however, helium is a noble gas and is therefore unreactive due to its complete valence electron shell. As a result, helium is the most viable gas for use in leak testing.

Helium leak testing is now available for all MATCOR linear anode products, however our Kynex connection technology has zero reported failures since it was introduced a decade ago.
Helium leak testing is now available for all MATCOR linear anodes, however our patented Kynex technology has zero reported failures since it was introduced a decade ago.

MATCOR has enjoyed an outstanding record as the world’s leading supplier of MMO anodes/Titanium linear anodes with over 25 years of linear anode experience supplying our industry leading SPL™ family of linear anode products for pipelines, tanks and other applications around the world. Our patented automated injection molded Kynex® connection technology has an outstanding track record with no known connection failures since this technology was introduced in 2009.

We do, however, see some client specifications calling for 100% connection testing and helium leak testing is the most effective means to test an entire anode assembly.


For more information, please feel free to contact your local MATCOR representative or contact us at the link below.

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Manufacturing Quality: What Does It Mean To Be Exceptional?

Manufacturing Quality for Anode SystemsAt MATCOR, we pride ourselves on being a world class manufacturer of unique cathodic protection systems and AC mitigation systems. Our anode systems offer you longer life, lower total installed cost, and are safer and easier to install than many conventional anode solutions. We have earned a reputation for exceptional manufacturing quality—but all companies say their products are world class and have exceptional quality, right? What makes MATCOR different? What does it mean to be exceptional?

At our state of the art Chalfont, Pennsylvania manufacturing facility we have developed a culture of quality. That is not to imply that we are perfect or that we don’t occasionally make a mistake; we are not perfect. However, we HAVE embraced, through our ISO Certified Quality Management System, a systematic approach towards excellence. So, while everyone aspires to do a quality job, our manufacturing team’s quality culture is based on perspiration—we work relentlessly to do a quality job for YOU by embracing the key tenets of quality.

Through our Manufacturing Quality Management System, we:

  • Document procedures for what we do
  • Train our team on the proper processes
  • Hold ourselves and our suppliers to high quality standards
  • Self-audit to ensure we are doing what we say we will do
  • Measure our performance daily through KPIs (key performance indicators)
  • Strive to continuously improve
  • Collect and act on YOUR feedback, comments and complaints

We’d love to hear from you about our manufacturing quality, please comment or contact us at the link below.


To get in touch with our team of cathodic protection experts for more information, to ask a question or get a quote, please click below. We will respond by phone or email within 24 hours. For immediate assistance, please call +1-215-348-2974.

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