24 Mar 2022

Atmospheric corrosion is the deterioration and destruction of metallic materials, as well as their structure and properties, caused by interaction with the terrestrial atmosphere at its various temperature, moisture, chemistry, and climatic values. Atmospheric corrosion is distinguished from the dry or gaseous corrosion at high temperatures in the absence of moisture, the latter form of corrosion does not require atmospheric humidity to occur. Dry or gaseous corrosion is a chemical corrosion and is quite different from atmospheric corrosion.

Many industries such as the Construction and Oil/Gas industries suffer from corrosion risks. As metal structures and equipment experience terrestrial air conditions and therefore can suffer from atmospheric corrosion and in some severe cases, the metal can be completely destroyed which can be quite costly and detrimental to the continuity of the operations. Fortunately, with sufficient background information of the various exposure conditions and how these influence metal corrosion, most serious corrosion problems can be reduced. This form of corrosion occurs spontaneously, however, it may be slowed, prevented, and controlled but never completely stopped.

Most used metals are not in a pure state. These metals are usually in ores, chemical compounds that include O2 (oxygen) , H2 (Hydrogen), and S2 (Sulfur). These represent the mineral compounds which are the thermodynamic steady state of the metals. For the separation of the metals from their ores and for metallurgical and manufacturing processes, energy, in the form of heat, chemical, electrical, or mechanical, elevates the metal to higher energy levels and the metal product is not thermodynamically stable. This drives metals to convert into corrosive products. When metals come in contact with the atmosphere (oxygen) and water (moisture) in the presence of corrosive compounds such as chlorides or sulfur dioxide corrosion starts, and corrosion products such as oxides, hydroxides, or oxyhydroxides are formed.

Most used metals are not in a pure state. These metals are usually in ores, chemical compounds that include O2 (oxygen) , H2 (Hydrogen), and S2 (Sulfur). These represent the mineral compounds which are the thermodynamic steady state of the metals. For the separation of the metals from their ores and for metallurgical and manufacturing processes, energy, in the form of heat, chemical, electrical, or mechanical, elevates the metal to higher energy levels and the metal product is not thermodynamically stable. This drives metals to convert into corrosive products. When metals come in contact with the atmosphere (oxygen) and water (moisture) in the presence of corrosive compounds such as chlorides or sulfur dioxide corrosion starts, and corrosion products such as oxides, hydroxides, or oxyhydroxides are formed.

Atmospheric corrosion is an aqueous process, and its mechanism is electrochemical. Meaning that there's both transfer of mass during the chemical change also as an interchange of electrons and ions. The flow of electrical current (transfer of electrons) only happens because of the buildup of galvanic corrosion cell on the surface of the metal. For this to occur, anode and cathode sites, an electrolyte, and an oxidizing agent must be present

  • - Anodes are the areas on the metal where several factors may be present such as inhomogeneous metal composition, grain boundary, multiple metallurgical phases, local metal defects, and nonuniform metal treatments - these form with a higher energy state.
  • - Cathodes however, are the areas with lower energy state such as inert non-metallic inclusions and lower active-metal phases or structures. The cathodic reaction occurs on these sites and involves the reduction of an oxidizing agent, such as air, oxygen, or hydrogen ions.
  • - An electrolyte, such as moisture, moisture contains dissolved atmospheric pollutants which works as an ionic conductor that will sustain electrochemical reactions.
  • - An oxidizing agent, such as O2 and H2 ions, and is necessary for accepting the electrons emitted from the metal in the anode reaction.

Figure 1 below shows the basic corrosion mechanism of iron under a drop of water. Both iron dissolution and oxygen reduction reactions take place with slight separation on the surface, and their products (Fe ions and OH ions) react in the water drop to form red rust (corrosion product). The simple model of the corrosion reaction of Figure 1 explains many forms of corrosion and help understand measures to reduce corrosion. By preventing or slowing down one of the partial reactions, the overall corrosion rate can be reduced.

There are two basic forms of Atmospheric Corrosion, uniform (general) and non-uniform (localized). Uniform corrosion results at a similar corrosion rate over the metal surface and has the same appearance throughout. Uniform attack is typical for atmospheric corrosion of steel and copper. On the other hand, non-uniform corrosion usually occurs at relatively small and specific areas on the metal surface where the corrosion process is focused, resulting in local accelerated corrosion rate (i.e. Pitting).

Metal cracking is a very dangerous type of atmospheric corrosion which can occur when a metal structure is exposed to a corrosive environment and continuous or cyclic mechanical loading. These conditions can be widely seen in construction and oil/gas industries where continuous cyclic mechanical loading is the nature of the metal exposure. This combination leads to micro cracks, fissures, and big cracks that result in stress-corrosion cracking (under relatively constant loads) or fatigue corrosion (under cyclic deformation).

Corrosion may be expensive if not properly managed. Corrosion is a constant issue in construction and oil and gas industries due to poor material selection. The projected yearly direct cost of corrosion in the United States is $276 billion. When selecting building materials and accessories, corrosion concerns must be seriously evaluated. Figure 5 shows an overall distribution of yearly cost of corrosion in the United Sates.

Yearly Cost of Corrosion in USA Figure 5 - Yearly Cost of Corrosion in USA
(Ref: http://impact.nace.org/documents/ccsupp.pdf)

It is evident that corrosion protection is often a necessary consideration in selecting materials for the construction and oil and gas industries and many others. Corrosion occurrence will reduce the load-carrying capacity of a component either by generally reducing its size (cross section) or by pitting, which not only reduces the effective cross section in the pitted region but also introduces stress raisers which can initiate cracks and reduce the lifetime of the structure. Many measures are present to reduce corrosion and extend the life of a component, increasing its overall reliability. The economics, environmental conditions, degree of protection needed for the projected life of the part, consequences of unexpected service failure, and importance of appearance are the main factors which determine not only whether a component needs to be protected against corrosion but also the most effective and economic method of achieving that protection.

Corrosion Protection Methods Figure 6 - Corrosion Protection Methods
(Ref: http://impact.nace.org/documents/ccsupp.pdf)

There are two methods of minimizing the corrosion of steels. The first is to separate the reacting phases, and the second is to reduce the reactivity of the reacting phases. The separation of the reacting phases can be accomplished by metallic, inorganic or organic coatings, and film-forming inhibitors. Reactivity can be reduced by alloying, anodic or cathodic protection, and chemical treatment of the environment. Some methods of protection combine two or more forms. In most environments, the corrosion rate of carbon steel is typically around 20 micrometers per year in a rural outdoor atmosphere and rising to more than 100 micrometers per year in coastal environments. It is normally too high for a satisfactory application. The product design does not generally account for a base material loss. Hence, cost-efficient corrosion protection solutions are necessary.

Coating material is a tried and tested approach for extending the life of a product by reducing corrosion risks. At Engineering Edge, we offer a wide range of innovative anti-corrosion fasteners that are guaranteed to perform in various corrosive environments. Check out our CORROSHIELD® coating technology for more details.

At Engineering Edge, we guarantee that each fastener undergoes extensive research and testing. Each fastener passes the most detailed quality checks to exceed your expectations and perform for a minimum number of years before becoming structurally unreliable due to premature corrosion.

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02 Mar 2022

Carbon steel fasteners used for construction are rarely sold raw, without any form of surface treatment. Surface treatment refers to the additional process applied to the surface of fasteners to bring about certain functions. The functions surface treatment may bring vary from rust prevention, wear resistance, temperature resistance, lubricity or merely decorative. CORROSHIELD® fasteners are available with a wide range of coating options for various applications and environment. As the name suggest, our focus is on rust prevention. CORROSHIELD® is the flagship brand of Engineering Edge (S) Pte Ltd in Singapore, and we have been manufacturing corrosion performance fasteners since 1989. In this article, we are pleased to share information about common coating used on smaller diameter construction fasteners.

Corrosion is a permanent deterioration of metal as a result of chemical reactions between it and the surrounding environment. For corrosion to happen, surrounding elements such as oxygen, moisture and impurities are present. Then an electrochemical reaction takes place as metal is returned to its natural state as iron oxide, or rust. Corrosion can happen because of weathering or chemical attacks.

CORROSHIELD®’s Corrosion Graph


There are international standards that provide guidelines in an attempt to govern the quality standards of coatings that are applied onto fasteners. Some of them are:

ASTM F1136/F1136M-11 Standard Specification for Zinc/Aluminum Corrosion
ASTM F1941/F1941M-16 Standard Specification for Electrodeposited Coatings on Mechanical
ISO 4042:2018 Fasteners – Electroplated Coating Systems
ISO 10684:2004 Fasteners – Hot Dip Galvanised Coatings

However, coating technology is evolving faster than any international standards can pen down. The evolution is moving rapidly towards nanostructures and nanomaterials, or smart factory to accelerate outputs and definitely quantum leaps in corrosion performance.


Today, there are several fastener coatings options available in the market. Too much to name in this single article. Every coating has its function and has a limit to its corrosion performance. Here are some of the more common ones that is used on smaller diameter fasteners.


Electroplating uses the power of electricity to deposit metal on the surface of various types of objects. In the case of fasteners, zinc is commonly deposited onto the surface to provide that protection. Corrosion protection achieved by electro zinc plating is very much dependent on the thickness that is applied. Electro zinc plating is one of the most economical ways of providing fasteners with corrosion protection. However, like all coatings, it has its limitations. Electro zinc plating is more suitable for small diameter fasteners, and one cannot plate too thick without bringing on the dangers of hydrogen embrittlement.


Organic coatings are made up mainly of additives and can be applied onto various surfaces. It can be monolithic consisting of one coat or two or more layers of coatings. Some critical manufacturing control parameters when applying organic coatings onto fasteners are viscosity control, evaporation for film formation, film adhesion and coating durability. The effectiveness of organic coatings is dependent on their chemical inertness and impermeability. The corrosion protection of fasteners provided by organic coatings relies on the capability to form highly resistive pathways between anodic and cathodic sites on the fastener surface.


Mechanical plating, unlike electro plating, does not use electricity or high temperature to plate a fastener surface. Instead, it is done in room temperature and uses kinetic energy to deposit coatings onto the fasteners. The process uses a rotating tumbling barrel to provide the mixing action. The fasteners are mixed with glass beads, water, surface preparation chemicals, promoter chemicals and metal powders within the tumbling barrel. The rotation causes metal powder to impact the surface of the fasteners thereby mechanically depositing the coating onto the surface.


E-Coating is also known as electrodeposition of coatings. It is a combination of Electroplating and Organic Coating mentioned above. In e-coating, the fasteners are dipped into a tank of coating materials like resins, pigments, and additives. These coating materials are mixed in water and circulated, and the fasteners are then immersed into the bath. Electrical currents are passed through the bath and as coating materials become insoluble, they adhere to the surface of the fasteners forming a layer of film.


Selection of fasteners with the correct coating type and grade can be a daunting task for any fastener buyers. This is made worse by the fact that there is very little knowledge and loads of misinformation issued by other fasteners sellers. However, fastener buyers can now positively identify the correct coating to be specified on their fasteners by speaking to Engineering Edge. Let us help you out with our 20 over years of experience in corrosion performance fastener. Our experts are ready to help you out and offer you obligation free information at info@engineering-edge.com.

CORROSHIELD®’s Corrosion Resistant Type

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02 Mar 2022

Which is better? Does one compliment the other? How does each test function as a legislative tool?

CORROSHIELD® SA had the opportunity to ask Mr. Jason Hoo, Managing Director of Engineering Edge (Singapore) Pte Ltd, about Real World vs. Laboratory Testing in the Roofing/Fastener industry.

Industry experts conduct laboratory testing within a controlled environment.

The focus is to maintain consistent contamination factors, providing control over the intensity of our testing to achieve specific results. Test results become inconclusive if we have other variables that interfere with the outcome of each particular test.

Our process

Laboratory testing provides a conducive environment for repeatability, which is essential when assessing results across multiple settings and products. Essentially, the convenience of repeating a test under exact conditions gives you the flexibility and accessibility of replicating an assessment with different samples.

Additionally, laboratory tests provide a high degree of objectivity among multi-sample comparisons while facilitating the easy addition of variables.

Many industries, such as medical science and aerospace, adopt laboratory testing due to its cost-effective results and seamless integration with existing manufacturing and administrative processes across organisations.

It is essential to note that laboratory testing operates with a statistical objective. You should handle each step of the process with care, as slight deviations in time can sway the results.

For example, it is common for some manufacturers to acquire a single laboratory test report and use it as a baseline accreditation for all of their product’s quality and consistency. Such a report usually remains in effect indefinitely. However, such a rigid and short-term approach often produces an inaccurate reflection of fastener performance beyond initial test results.

At Engineering Edge, we prefer to carry out similar tests with multiple parties for all products (including CORROSHIELD® and TAPPERMAN® brands). Our comprehensive approach involves tests at production, QA. R&D, and 3rd party level to achieve and maintain accurate results.

Our team performs the evaluations on every product batch over an extended time. Through constantly dedicated data collection and analysis, we acquire accurate product information that drives the consistent manufacturing of quality products.

With a combination of fixed parameters and distributor feedback from the Delivery Irregularity Report (DIR) protocol, Engineering Edge modifies products promptly to fulfill specific applications and end-user requirements.

In my years as a manufacturer, I observed that most local fastener importers lack a real say on testing processes and related data when purchasing from an exporter. In most cases, manufacturers may conduct multiple one-time tests followed by short-term comparisons that define the product “quality”.

Such practices lead to confusion and unreliability among the local market. On the contrary, laboratory test results should remain dependable and, they ultimately rely on how manufacturer performs their tests.

We are EN 10204 Compliant
Real-World Testing

With all other considerations aside, real-world testing does offer one advantage. It gives us an alternate perspective. Despite uncontrollable and unaccountable variables, such as changing climate, pollution levels, and workmanship, the real-world testing results give us a snapshot of how products perform during a given duration within a specific location.

However, regarding professional bodies and their opinion on real-world vs. laboratory testing, I cannot imagine real-world testing adopted as a unit of measure for performance. The main issue lies in its inconsistent unit of measurement, and I hope that these professional bodies can see this objectively.

Today, algorithmic decision-making (computer-based management of vast quantities of quality data used in processes, tests, and analyses) is the future.

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12 Jan 2022

At Engineering Edge, we aim to provide end-users with durable fasteners for various applications. Corrosion resistance is a crucial quality control criterion in fastener manufacturing. Fasteners susceptible to corrosion will result in costly rectifications, which affect the ROI and efficiency of a project.

That’s why we believe in subjecting our fasteners through strict quality checks such as salt spray tests to determine the highest product standards for our partners.

Salt Spray Tests - Anti-Corrosion Assessment

A salt spray test is one of the most basic anti-corrosion assessments used by several industries. These tests usually involve metallic substrates like fasteners, pushing their threshold by contaminating them with salt mist in a temperature-controlled chamber over a fixed duration.

CORROSHIELD®’s corrosion-resistant fasteners CORROSHIELD®’s corrosion-resistant fasteners

The sealed chamber simulates specific contaminations within real-world environments. When salt attaches itself to metallic surfaces, it strips away electrons that protects those areas. The movement of these electrons results in oxidation. Hence, the Salt Spray Test assesses the anti-corrosion capabilities of metallic and coated products.

However, it would be inaccurate and even costly for decision-makers to rely solely on Salt Spray Test in assessing the anti-corrosion performance of metallic products.

Consulting Multiple Anti-Corrosion Tests

Modern manufacturers discovered that the findings from salt spray tests are non-conclusive. For example, while a fastener product could pass a salt spray test with flying colours, it might yield poor results with acid or humidity testing.

In reality, it is imperative that manufacturers adopt a broader understanding when it comes to anti-corrosion testing and establishing a correlation between accrued results. There are several types of anti-corrosion assessments aside from Salt Spray testing. Two examples of alternative anti-corrosion tests are:

Alternate Immersion

Alternate immersion tests assess the anti-corrosion properties of coatings under wet and dry conditions. These advanced tests involve rotating a coating sample in environments of varying moisture levels.

Specifically, alternate immersion helps detect stress corrosion, which occurs when products immersed in water start to show signs of cracking. Assessing the severity and frequency of cracking prevents the production of fasteners that degrade or buckle easily when constantly exposed to moisture (i.e., bridge installations).

Humidity Tests

Humidity tests like the ASTM D2247 utilises enclosed chambers that increase the moisture content within the test area. The ASTM D2247 checks specifically for how anti-corrosive coatings hold against water impact and wet conditions that accelerate the chemical breakdown of metal components.

At Engineering Edge, we ensure that our fasteners undergo and pass rigorous assessments across multiple test types to fulfil the highest quality.

Engineering Edge’s Premium Fasteners

The Engineering Edge mission began with a focus on manufacturing corrosion-resistant fasteners for hostile outdoor applications.

We offer a premium range of CORROSHIELD® coating solutions suitable for various applications. Additionally, these fasteners come with innovative features prepared and tested for the most hostile environments.

Examples of our range of specialised corrosion-resistant fasteners includes PROTAPP® that features a reinforced fit alternate non-metallic double hex flange head and BIMATAPP® that combines stainless steel and carbon steel into a single fastener, minimising galvanic reaction towards non-suitable materials.

At Engineering Edge, we guarantee that each fastener undergoes extensive research and testing, passing the most detailed quality checks to exceed your expectations.

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14 Dec 2021

The engineering industry focuses on precision, quality, and consistency. Our founder, Jason N Hoo, prioritised these characteristics when he discovered the gap between the vision of manufacturers and the fastening solutions available in the market. He decided to embark on the Engineering Edge journey more than two decades ago to turn expectations into a reality.

Being at the cutting edge of engineering requires a constant understanding and fulfillment of the needs of end-users on the ground. Jason realised that companies could achieve a more significant ROI with their existing workforce by delivering effective fastening solutions to the market.

Specifically, there was a need to address the “fastener issue.”

Fasteners make up approximately 1% of the total project cost, yet, they are indispensable across various projects. Essentially, these small components hold complex structures securely in place, and there is no one-size-fits-all solution. Yet, many companies overlook the importance of fasteners, resulting in high maintenance costs, shorter product lifespans, and safety concerns.

With that concern in mind, Jason explored, researched, and curated a broad range of fasteners that serve specialized purposes. Engineering Edge’s innovative lineup includes self-locking fasteners for structural joints, speed drill designs for higher output, self-tapping concrete screws, and many more.

For example, the team recommends the S17 drill point as a replacement for conventional timber application fasteners. The drill points feature wider angle sharpness that enables users to cut through dense timber with ease.

S17 drill points picture S17 drill points

Another innovative solution is CORROSHIELD®’s DUOTAPP™ fasteners that feature one point with two applications (i.e., suitable for steel and timber). By implementing DUOTAPP fasteners, teams can reduce cost, time, and storage space for their projects. Additionally, with the dual-purpose design, there is no need for users to undergo product differentiation training.

Engineering Edge remains a dedicated manufacturer of fastening solutions based in Singapore, with factories situated in Taiwan and Vietnam. The Engineering Edge team dedicates itself to building and nurturing long-term partnerships through the power of specialized innovation.

A senior member of the Engineering-Edge team shares, “We believe in exceeding all project expectations every time, without fail. Our tireless mission is to supply and deliver the most effective solutions that leave clients with the best impression that earns their trust.”

Engineering-Edge continues to “create an edge,” serving the global community through authorised distributors and seasoned engineers in over 20 countries.

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