What Are Corrosion Coupons?

Corrosion coupons are used to measure the corrosion rate of the system. Like oil and gas pipeline systems, water systems, chemical systems, etc. We provide different types of corrosion coupons, such as strip coupons, disc coupons, and coupons with multiholes. The surface of the coupons also has many choices, such as a grit blast finish, a glass beads surface, coarse grit blasted, mill finish, or no treatment. If you want corrosion coupons for other requirements, contact us. We will recommend the most suitable cleaning solution based on our experience.

Shape of The Corrosion Coupons

According to different needs, we provide two types of corrosion coupons: strip coupons and disc coupons.

Strip Coupon

There are two types of strip coupons: strip coupons and multihole strip coupons.

1. The common size of the strip coupon with 2 mounting holes is 3” ×3/4” ×1/16” (76.2mm ×19.0mm ×3.2mm).

2. The common size of the strip coupon is 3” ×1/2” ×1/16” (76.2mm ×19.0mm ×3.2mm)

Disc Coupon

1. The regular size of the disc coupon is Φ1.25” (31.8mm) with a thickness of 1/16” (3.2mm) and 1 mounting hole.

Material of The Coupon

We offer a wide selection of materials.

Standard alloys

C1010 carbon steel, C1018 carbon steel, 316L SS, 304SS

Other alloys

Aluminum 1100, C276, alloy 625, CDA110, CDA443,

If you have other material requirements, don’t hesitate to get in touch with our EMT team. We will do our best to meet your requirements for the product.

Parameters

Product Selection Table

Should you be interested in purchasing our EMT corrosion coupons, please refer to the provided selection table to choose the appropriate type for your needs. For any specific requirements or queries, do not hesitate to reach out to our EMT team. Rest assured, we will offer you the best solution based on our extensive expertise and years of experience.

Surface Treatment Mode

1. Grit blast finish

Grit Blast Finish helps to clean off any dirt, unwanted stuff, or rust. It makes the metal’s surface even and ready for painting or coating. Doing this helps paint or other coatings stick to the metal better, which is useful if you want to add layers later on.

2. Glass beads surface

Utilizing fine glass beads in a blasting process, this treatment will not cause damage to the material. The glass beads gently remove surface deposits and leave a clean, bright, and satin-like finish. Often used for aesthetic purposes, this method is also effective for cleaning without altering the dimensions or shape of the part.

3. Coarse grit blasted

Similar to grit blasting, this mode uses larger and coarser particles of abrasive materials to aggressively treat the surface. It’s designed for heavy-duty applications. More substantial surface preparation is needed, such as for removing thicker layers of rust or old coatings. It prepares the surface for coatings that require a rougher profile for better adhesion.

4. Mill finish

This is the natural appearance of the metal as it comes from the rolling mill or the extrusion process. It is without any additional surface treatment, which means it may contain some manufacturing marks and slight imperfections. For applications where surface aesthetics are not a primary concern or where the customer will perform additional finishing, mill finish is frequently sufficient.

5. The surface is not treated

In this mode, the metal is provided as-is, without any form of surface treatment. You may opt for this treatment when you plan to perform your customized surface preparation or when the inherent properties of the metal are sufficient for the intended use.

How to Calculate Corrosion Rate through Corrosion Coupons

Through the reducing weight of the sample coupon, the operators can calculate the corrosion rate using a straightforward ASTM formula.

The following is the corrosion rate calculation formula:

V: Corrosion rate (μm/year)

M∆: Sample weight change (mg)

ρ: Alloy density (g/cm³)

S: Sample area exposed to the environment (cm²)

t: Duration of exposure (h)

K: Fixed coefficient (10⁶*8.76، With units used for other terms)

Here’s an accurate description of the process for calculating the corrosion rate using the ASTM standard formula:

1. Corrosion Rate (V): This is what you want to find out. It tells you how fast the metal is corroding and is measured in micrometers per year (μm/year).
2. Sample Weight Change (M∆): This is the amount of weight your corrosion coupon has lost during the test. You need to measure this in milligrams (mg).
3. Alloy Density (ρ): Each metal or alloy (which is a mix of metals) has a density, meaning how much a certain volume of it weighs. You’ll need this number for your specific metal, and it’s measured in grams per cubic centimeter (g/cm³).
4. Sample Area (S): It is the surface area of your coupon that was exposed to the environment where you’re testing for corrosion. It’s measured in square centimeters (cm²).
5. Exposure Duration (t): This is how long you left your coupon in place to face the corrosive environment. You’ll need to record this in hours (h).
6. Fixed Coefficient (K): It is a constant number used in the formula to make sure all the units work together correctly. It’s based on the number of hours in a year and converts the corrosion rate into the desired units of micrometers per year.

Importance of Monitoring Corrosion on Pipelines

Monitoring corrosion in pipelines is critical because it can cause damage, leading to leaks, expensive repairs, and safety hazards. Corrosion can disrupt operations and result in additional costs from downtime, environmental impact, and fines. Particularly for pipelines with dangerous materials, the risks include contamination and accidents. Therefore, regular checks are essential to keep pipelines safe and working well.

Conclusion

In conclusion, corrosion coupons are vital for tracking material corrosion, especially in systems such as pipelines. They come in a range of shapes and materials, each tailored to particular environmental conditions. The precise size and finish of each coupon are critical to ensuring the accuracy of the tests. Utilizing ASTM formulas, operators can analyze the data to determine corrosion rates, expressed in micrometers per year. This crucial knowledge informs maintenance decisions and contributes to the longevity of the system. It also guides the selection of protective measures and materials designed to resist corrosion. Ultimately, safety, efficiency, and cost savings all depend on a clear understanding of corrosion rates. Therefore, corrosion coupons play a key role in maintaining the integrity of various systems.

To further manage and mitigate corrosion, chemical injection quills are an effective solution for your pipe systems. By employing corrosion coupons, operators gain insights into the current corrosion rate. Should this rate prove excessive, chemical injection quills can be introduced to dispense corrosion inhibitors into the system. These inhibitors are designed to slow down the corrosion process, thereby protecting the pipes and extending their service life. Our commitment is to deliver top-quality corrosion coupon products, prioritizing customer satisfaction at all times.

Our Service

We offer a wide range of corrosion coupons. They can meet diverse corrosion monitoring needs. Accordingly, we invite you to contact us to find a solution that best fits your requirements. To further demonstrate the high quality of our products, we provide the option for clients to request sample units.

Additionally, we take pride in our prompt customer service. Consequently, our team is readily available to provide immediate feedback and address your inquiries. Moreover, we aim to provide the fastest possible delivery times, ensuring you receive your orders promptly. Furthermore, our online support is available around the clock, operating 24 hours a day, 7 days a week.

Packaging and Delivery
Our products are packaged in cases, which include carbon boxes and Polywood boxes. They offer the following benefits:

1. Carbon boxes are cost-effective, lightweight, and customizable, making them ideal for a variety of products, especially for reducing shipping costs. They also offer good shock absorption and are environmentally friendly due to their recyclability. Polywood boxes, on the other hand, are sturdy and provide excellent protection for heavier items. They are weather-resistant, reusable, and can be securely closed, which makes them suitable for valuable goods and long-term storage or repeated shipping.