Typical Value in Seal - HNBR 1

[JHWC]

Hi All,

The team that I work with is require to buy a HNBR seal.

The vendor has provided us with 1 catalogue with the test values given (attached).

I am interested to know about the immersion test. I have downloaded the required ASTM (471 and 5964) for my references.

2 questions I want to ask :

1. How and where can I compare the typical value for HNBR under ASTM IRM 903 Oil?
2. The typical value for immersion test usually come with a (+/-) sign. What does this mean and how should it be correlated?

Thanks for the explanation in advance.

Cheer,
Jeffrey

 

[dgallup]

Look for specifications ASTM D2000 / SAE J200 for classification of rubber materials. These will give you the typical pass/fail requirements for nearly all grades of rubber compounds based on basic temperature and volume swell criteria. This is a rather complicated system of line callouts that are used to specify the various tests and what their pass/fail criteria are. Of course you need to know what your application requirements are. What you have are the measured results, what you are looking for are the allowable range of results.

A typical HNBR compound using the D2000 / J200 system might be specified as M2DH710A26B36EO16EO36F17. In this case the EO36 part of the line callout is the IMR903 immersion at 150 degrees C for 70 hours. Grade 2 has allowable pass/fail limits of:
Volume +25% max
Hardness Change -15 points max
Tensile strength change -40% max
Ultimate elongation change -40% max

Again, it is up to you to establish what your specific application requires and how to properly specify them.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[JHWC]

Thanks dgallup for the information. Very helpful indeed. =)

Cheers,
Jeffrey