Hardness vs. Elastic Modulus
Hardness vs. Elastic Modulus
(OP)
Hello, first post here...
I'm trying to calculate the contact stress between a metal pin and a flat metal plate. The pin is a 1045 steel that is through heat treated to a hardness of 45HRC. In order to calculate the contact stress between the pin and the plate using Hertzian's contact equations, I must know the elastic modulus of the 45HRC 1045 pin.
Without doing a tensile test on the part, is there a good way to correlate elastic modulus from a hardness measurement?
Regards,
Drew
I'm trying to calculate the contact stress between a metal pin and a flat metal plate. The pin is a 1045 steel that is through heat treated to a hardness of 45HRC. In order to calculate the contact stress between the pin and the plate using Hertzian's contact equations, I must know the elastic modulus of the 45HRC 1045 pin.
Without doing a tensile test on the part, is there a good way to correlate elastic modulus from a hardness measurement?
Regards,
Drew





RE: Hardness vs. Elastic Modulus
RE: Hardness vs. Elastic Modulus
From college I thought that by modifying the amount of carbon in steel, you couldn't change the modulus, but I wasn't sure about the effect of heat treatment on Young's modulus.
RE: Hardness vs. Elastic Modulus
thread330-87802: SA-516-70 at Elevated Temperatures
Nick
I love materials science!
RE: Hardness vs. Elastic Modulus
" All that is necessary for triumph of evil is that good men do nothing".
Edmund Burke
RE: Hardness vs. Elastic Modulus
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Hardness vs. Elastic Modulus
So I'm confused because I thought that hardness was essentially a measurement of a materials ability to resist deformation from a harder material, which seems to me like stiffness, i.e. Elasticity.
Any guidance on my mis-interpretations would be appreciated...
Thanks
RE: Hardness vs. Elastic Modulus
Regards,
Cory
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RE: Hardness vs. Elastic Modulus
The deflection limit at which you will start to get permanent deformation is a function of strength (proportional to hardness).
Two bars of identical geometry, one annealed 1005 and the other Q&T 4340, will deflect the exact same amount at light loads. The alloy steel bar will be able to defect much further before becoming deformed because it is stronger.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Hardness vs. Elastic Modulus
i API RP 579.
Cormet
RE: Hardness vs. Elastic Modulus
Now I'm running into another issue for my calculation which is trying to predict the yield strength of a cold worked part. The part is a hollow tube, extruded from 1020 steel, and then has two slots pierced into its sides. I'm running Hertzian equations to predict the compressionial stress for the given loading scenario that we have on the slots(cylinder on flat plate), but I'm predicting quite large failure on the softer 1020 tube, but in fact there is no failure there, I supspect because the slot is highly work hardened in that area.
So, is there a good way to theoretically calculate the local yield strength in the slot area, or should I simply try to take the hardness on that slot (easier said than done) and try to correlate that to a yield strength?
Any help is extremely appreciated...
Thanks! - Drew