Material properties for AISI 1045 steel

[PhilLee]

I have the following data for some AISI 1045 steel bar stock I have.

Heat number C39764
hardness 248 BHN

I need the material properties such as Fsu, Fcy, etc

I can't find it in my normal reference, MIL-hndbk-5.

Thanks!

 

[israelkk]

I don't think that AISI 1045 is used much (if all) for airborne and military use. I do not know of a aircraft quality spec for AISI 1045. This is probably the reason it is not included in MIL-HDBK-5. However, "MIL-H-6875 HEAT TREATMENT OF STEEL, PROCESS FOR" gives the tensile strength as a result of the different tempering temperature after quenching.

 

[israelkk]

Have found federal standard "QQ-S-634A STEEL, BAR, CARBON, COLD FINISHED, (STANDARD QUALITY)" However there is no requiremenmts for strength but only chemical contents

 

[kenvlach]

“Heat number C39764” is meaningless without certs; probably refers to an alloy analysis but could be a heat treatment.

The “hardness 248 BHN” (if done with a 10-mm ball and 3000 kg_f load) is approximately equal to HRC 24 or VHN 261 and indicates an approximate tensile strength of 120 ksi. – from ASTM A370.

There are 13 listings for 1045 steel at

http://www.matweb.com,

but none closely match yours (and none for Q & T condition).
Without both the mechanical and thermal history, the properties are rather undefined.
From the hardness, which is well below the maximum hardness (about HRC 58) possible with this alloy, a wild guess is hot-rolled material of ~80 ksi yield stress and ~20% elongation. Perhaps, this is material meant to be heat treated after machining.

 

[unclesyd]

This material was commonly used where induction hardening was called out. How the bar got to it's present condition could be rather convoluted as it can be either water or oil quench. I don't have any property or mass effect data for 1045 but I have data for 1040 and 1050, both oil and water quenched. Doing a little interpolation between the two sets of data and curves the material you have appears to have undergone some heat treatment as it doesn’t fall in the normalized or annealed hardness range.

One other thing as 1045 is not considered a through hardening steel, i.e. the reason for the induction hardening label. This make determining the physical properties a little more difficult.

If I remember correctly the bar (2&quot we used for shafting was supplied as CR, Q, oil, T @ 1000°F. After machining our material was induction hardened in the bearing areas.

If you can't backtrack the heat number to an MTR or the material is going into a critical component I would scrap it and start anew with a known material. Connecting to an MTR isn’t as hard as it once was because so many suppliers have the data online. If you know who your supplier was put the burden on his back as he has the knowhow and means to track the material.

The only other alternative, if not for a critical part, is to Normalize and Heat treat to a known condition then derive you require data (estimated) from the final hardness. This again is tricky as the material isn't a through hardening steel.

 

[MetalMickey]

May sound a bit simple, but since it's only bar stock, to be sure about the material get a piece tested and your local Material Labs or University. A quick micro would also be able to judge it's thermal history. This is the best way to be sure and should only take a couple of days.