How to determine if a Rubber Washer HNBR is of high quality?

Hey there! As a supplier of Rubber Washer HNBR, I've dealt with tons of these washers over the years. One question I get a lot from customers is, "How can I tell if a Rubber Washer HNBR is of high quality?" Well, in this blog, I'm gonna share some tips on just that.

1. Material Inspection

First off, let's talk about the material itself. HNBR, or Hydrogenated Nitrile Butadiene Rubber, is known for its excellent resistance to heat, oil, and chemicals. A high - quality Rubber Washer HNBR should be made from pure and well - processed HNBR.

• Visual Inspection: When you first get your hands on a Rubber Washer HNBR, take a good look at it. The surface should be smooth and free of any visible cracks, bubbles, or impurities. If you see any rough patches or unevenness, it could be a sign of poor manufacturing. For example, if there are small holes or air bubbles on the surface, it might affect the washer's sealing performance.
• Smell Test: Sounds a bit odd, I know. But a high - quality HNBR washer usually has a mild, rubbery smell. If it has a strong, unpleasant chemical odor, it could mean that there are some low - quality additives or improper curing processes involved.

2. Physical Properties

The physical properties of a Rubber Washer HNBR are crucial in determining its quality. Here are some key aspects to consider:

• Hardness: The hardness of an HNBR washer is typically measured on the Shore A scale. For most applications, a hardness range of 60 - 90 Shore A is common. You can use a hardness tester to check this. If the hardness is too low, the washer might deform easily under pressure. On the other hand, if it's too high, it may not be able to conform well to the mating surfaces, leading to poor sealing.
• Tensile Strength and Elongation at Break: These properties indicate how much stress the washer can withstand before breaking and how much it can stretch. A high - quality Rubber Washer HNBR should have good tensile strength and elongation at break. You can refer to the manufacturer's specifications to get these values. For instance, a washer with a high tensile strength can better handle the forces exerted on it during operation.

3. Chemical Resistance

One of the main advantages of HNBR is its excellent chemical resistance. A high - quality Rubber Washer HNBR should be able to withstand exposure to various chemicals without significant degradation.

• Oil Resistance: Since many applications involve contact with oil, oil resistance is a key factor. You can perform a simple oil immersion test. Take a small sample of the washer and immerse it in the relevant oil for a certain period (usually 24 - 72 hours). After that, check for any changes in weight, volume, hardness, or appearance. If there are significant changes, such as excessive swelling or a large decrease in hardness, it may not be a high - quality washer.
• Chemical Compatibility Chart: It's also a good idea to refer to a chemical compatibility chart. This chart shows which chemicals an HNBR washer can safely come into contact with. If a washer is claimed to be suitable for a wide range of chemicals but fails the actual tests, it's a red flag.

4. Temperature Resistance

HNBR washers are often used in applications where they are exposed to high temperatures. A high - quality Rubber Washer HNBR should have good temperature resistance.

• Heat Aging Test: You can simulate high - temperature conditions in a laboratory by placing the washer in an oven at a specific temperature (usually around 120 - 150°C) for a certain time (e.g., 70 hours). After the test, check for any changes in physical properties such as hardness, tensile strength, and elongation at break. If there are only minor changes, it indicates good temperature resistance.
• Operating Temperature Range: Make sure to check the manufacturer's specified operating temperature range. If the washer is supposed to work at high temperatures but starts to degrade at a relatively low temperature, it's not a good sign.

5. Dimensional Accuracy

The size and shape of a Rubber Washer HNBR are important for proper installation and sealing.

• Diameter and Thickness: Use a caliper to measure the diameter and thickness of the washer. The dimensions should match the specified values within an acceptable tolerance. For example, if the tolerance for the diameter is ±0.1 mm, and the measured value is outside this range, it may cause problems during installation.
• Flatness: The washer should be flat. You can place it on a flat surface and check if there are any gaps or unevenness. A non - flat washer may not seal properly, leading to leaks.

6. Compression Set

Compression set is a measure of how well a rubber washer can return to its original shape after being compressed. A high - quality Rubber Washer HNBR should have a low compression set.

• Test Method: You can compress the washer between two flat plates to a certain percentage of its original thickness (usually 25%) for a specified time (e.g., 22 hours at a certain temperature). Then, release the pressure and measure how much the washer has recovered. A lower compression set means better sealing performance over time.

7. Sealing Performance

Ultimately, the main purpose of a Rubber Washer HNBR is to provide a reliable seal.

• Leak Test: You can perform a simple leak test by assembling the washer in a test fixture and applying pressure or a fluid. Check if there are any leaks around the washer. If there are leaks, it clearly indicates a problem with the washer's quality.

Now, if you're in the market for high - quality Rubber Washer HNBR, we've got you covered. Just like our FKM Black Rubber Washer and NBR Black Rubber Washer, our Rubber Washer HNBR is manufactured with strict quality control to meet your requirements. If you have any questions or are interested in purchasing, feel free to get in touch with us for a detailed discussion. We can provide you with samples and technical support to ensure you get the best product for your application.

References

• "Rubber Technology Handbook" by Werner Hofmann
• "Elastomers and Rubber Compounding Materials" by Brydson, J. A.