ASTM D1415 vs. D2240 Type M micro-hardness testing
ASTM D1415 vs. D2240 Type M micro-hardness testing
(OP)
Hi all,
I am looking to better understand the differences between ASTM D1415 and ASTM D2240 for type M micro-hardness testing. I have had some O-rings tested at two different labs. One lab used D2240 and the other used both D1415 & D2240. The D2240 results from both labs matched however the D1415 test results varied. After reading the ASTM sections the only differences I can come up with are the time dependency and the actual test apparatus. Could anyone better explain the differences between the two? Material is NBR rubber. I'm new to the rubber scene so any help is appreciated!
Thank you for any and all tips!
Pat
I am looking to better understand the differences between ASTM D1415 and ASTM D2240 for type M micro-hardness testing. I have had some O-rings tested at two different labs. One lab used D2240 and the other used both D1415 & D2240. The D2240 results from both labs matched however the D1415 test results varied. After reading the ASTM sections the only differences I can come up with are the time dependency and the actual test apparatus. Could anyone better explain the differences between the two? Material is NBR rubber. I'm new to the rubber scene so any help is appreciated!
Thank you for any and all tips!
Pat





RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
Something I should have included before:
The test results using D2240 Type M were found to be a 70 Durometer however the D1415 Type M test results yielded between 50 and 60 Durometer. In this case which test should one believe? Are the results even comparable in the same scale?
Thanks Again
Pat
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
- Is there any reason not to believe both? The compound has a D2240-M hardness of 70 and D1415-M hardness of ~55. I think it depends on what what specification or requirements you're trying to meet, or what the customer wants. If the specification that needs to be met is an ASTM D2000 callout, for example, then D2240 hardness is specified.
I think it's like tear strength; there are several different test methods (e.g., angle, crescent, nicked/unnicked, trouser) and none of the results necessarily relate to each other. So, if somebody wants 200 lb/in tear strength, it has to be clarified what method (D624 Type C or B or T, for example) is used.
"Are the results even comparable in the same scale?"
- I wouldn't think so.
Good luck!
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
Have a look at the paper 'Comparison of results and test methods using the Micro IRHD and the Micro Shore rubber hardness measurement instruments' by R. Morgans (University of Greenwich). and S. Lackovic and P. Cobbold (Both H W Wallace). It is easy to find on the web. Interestingly they report higher numerical values for IRHD than for Shore A.
If something is amiss I think it may well be with the quality of the D 1415 test
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
Note: Material 1 and Material 2 should be the same.
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing
i would try to get a measure of how the IRHD reading changes throughout the 30 secs and compare this will the same test using the durometer. If the IRHD reading is always well below the Shore A one I would start to get a little suspicious.
RE: ASTM D1415 vs. D2240 Type M micro-hardness testing