Issue with tensile test of 61HRC tool steel
Issue with tensile test of 61HRC tool steel
(OP)
Hi All,
I have a strange requirement to tensile test a tool steel at 61HRC with spec limits of 2700MPA UTS, 1% elong & 2% ROA and it's not going well and our lab has no experience of testing material this hard. To start with, the threads on the tensile piece are fracturing, making it very hard to get a sensible stress strain curve, which is making me think that tapered samples are a must for this sort of test. When we do manage to coax the machine into running the test, it's fracturing in a brittle manner well below the requird UTS, typically at the taper where the tensile gauge length meets the threaded portion, and often in two places at once. This is making me think that the issue here could be the sample rather than the material, and we should be looking at the tensile specimen (surface finish / tensile geometry etc.). Does anyone have any experience tensile testing things this hard? Are we missing a trick?
Thanks for any help.
I have a strange requirement to tensile test a tool steel at 61HRC with spec limits of 2700MPA UTS, 1% elong & 2% ROA and it's not going well and our lab has no experience of testing material this hard. To start with, the threads on the tensile piece are fracturing, making it very hard to get a sensible stress strain curve, which is making me think that tapered samples are a must for this sort of test. When we do manage to coax the machine into running the test, it's fracturing in a brittle manner well below the requird UTS, typically at the taper where the tensile gauge length meets the threaded portion, and often in two places at once. This is making me think that the issue here could be the sample rather than the material, and we should be looking at the tensile specimen (surface finish / tensile geometry etc.). Does anyone have any experience tensile testing things this hard? Are we missing a trick?
Thanks for any help.





RE: Issue with tensile test of 61HRC tool steel
You may have to come up with a larger thread size to reduce the thread stress level and prevent the cracking.
Who designs a tensile loaded part up into the brittle fracture zone? I hope I don't ever have to be around this part when it is in service.
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
RE: Issue with tensile test of 61HRC tool steel
either spherical ends or flat button ends in gimbaled mounts.
And I hope that your machine is stiff, my hunch is that if fracture is over 50% of your rated machine load then you are probably bending the sample.
We used to test high tensile wire, we had to use optical strain gages because the elongations were so small.
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Plymouth Tube
RE: Issue with tensile test of 61HRC tool steel