Coil Coatings Simulated Weather Testing

The premature failure of a coating in harsh environmental conditions can spell disaster. Companies often conduct long-term tests in challenging climates, but there is a quicker way to tackle the issue. Exeter Advanced Technologies (X-AT) is taking a different approach by studying how environmental conditions impact the mechanical properties of standard coil coatings in a lab setting. This allows for a more efficient and focused analysis of product behavior under simulated conditions. In this post we follow the journey taken by a top global supplier of industrial coatings and a leading provider of coil coatings, from start to finish.

steel cladding commercial building grey sky rain
It can be quite a challenge to accurately determine manufacturer guarantees for cladding made from coated coiled steel, as testing in real-world conditions can take several years.

About coil coatings

Coil coatings are applied to protect various surfaces from environmental conditions such as heat, cold, humidity, and corrosion, particularly in coastal areas. They are used on building cladding, appliance carcasses, automotive panels, and other industrial applications.

Exterior paints must be corrosion-resistant, color-stable in UV light, durable, and resistant to dirt pick-up. Paint for domestic appliances should be resistant to knocks and stains, and able to bend without cracking.

coil coatings roof sheets
Coated coiled steel ready for roll forming and cutting machine.

Benefits of early testing

In order to gain a comprehensive understanding of how external coatings perform in various global environments, it is essential to conduct testing in real-world settings. However, this is not always feasible, so it is crucial to gather high-quality data on how coil coatings react under specific conditions. Simulating extreme weather scenarios becomes necessary when on-site testing is not an option. This practice allows paint manufacturers to adapt and refine their coating systems more efficiently during the development phase.

By analyzing the behavior of coatings in different climates, companies can make informed decisions to improve product long term performance.

Environmental control chamber

The coil coatings manufacturer is passionate about innovation and pushing boundaries. Always concious that in order to stay ahead of the competition, they needed to invest in cutting-edge technology. Collaboration with a university was a necessity to create an environmental control chamber that could be used in conjunction with a tensile testing machine. Partnering up with Exeter Advanced Technologies (X-AT) took the project to the next phase. With their expertise and state-of-the-art equipment, they were able to develop a solution that met the manufacturer’s needs. Together, they were able to push the boundaries of what was possible in the world of coil coatings.

humidity chamber testing coatings
Humidity testing chamber.

Testing equipment

The X-AT laboratory is equipped with a Lloyd Instruments EZ20 universal testing machine, featuring a 20kN force capacity and 1000Hz data sampling rate. This machine is ideal for testing thin paint film samples required by BIC. The twin column frame ensures accuracy when used with thermal cabinets and environment chambers, allowing for precise tensile to break tests on thin film coatings at controlled humidity and temperatures from -30 to +60ºC.

ez20 universal testing machine
Lloyd EZ20 universal testing machine.

Adapting environment chambers

X-AT replicated end user environment conditions accurately by adapting environment chambers and thermal cabinet attachments. This allowed for prediction and adjustment of system properties affected by humidity and liquid immersion before exposure to extreme conditions.

Humidity simulation

Samples were tested in a humidity chamber and thermal cabinet to simulate varying humidity and temperature conditions. An oven filled with water was used to replicate wet conditions.

Samples were tested in tension underwater using a special immersion jug. The EZ20 was controlled by Lloyd Instruments’ NEXYGENPlus software, which is fully Windows compatible and has a large library of international standard test setups for manufacturing compliance.

Tensile test and a peel test

Two types of tests were conducted on coil coatings: a tensile test and a peel test. Tensile samples measuring 30 microns in length were coated, cured, and tested using specially designed grips. Tests included tensile to break and creep tests under controlled load, repeated in various environmental conditions. Data was stored and analyzed using standard tensile test set-ups in NEXYGENPlus software.

profiled steel wall cladding sheets
Profiled steel wall cladding sheets, image courtessy of ©TATA Steel.

Further reading

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