4130 Alloy steel HRc 55 Question.

[NickE]

I need a rough estimate for yield and UTS for 4130 alloy stamped (cold) from annealed coil and then Q&T hardened to 55HRc. The part is roughly rectangular and 6mm x 13mm x 50mm.

Thanks.
nick

 

[unclesyd]

Are you sure you have 4130 CS?

You would be hard pressed to get a an as quenched hardness of HRc 50 with 4130 with a water quench from 1575°F.


Tempering at 325°F to 400°F after water quench would give a max of HRc of 49.
TS 233,000 psi
YS 198,000 psi

 

[metengr]

For 4130, the maximum hardness (quenched) I am showing is about 50 HRc at 1/16" from an end quench hardenability curve provided by Ryerson.

For 4130H, the maximum hardness reported is 54 HRc at 1/16" from an end quench hardenability curve.

unclesyd - your UTS and YS data for 4130 correlate with what I have from Republic Steel Corp. Normalized at 1600 deg F, quenched 1575 deg F in water, and drawn at 400 deg F for 1 hour.

 

[unclesyd]

metengr,
Evidently NickE has the H grade.

My data probably predates yours by several years as it was published as Modern Steels and their Properties by Bethlehem Steel in 1952 a year before I got my copy.

I hate to see materials like 4130 made in an H grade as it defeats one of the primary reasons for using 4130 in lieu of 4140 the weldability. This is especially true of users were it will "just as good as" 4130 until there are failures during and after welding.

 

[NickE]

Actually the part only exists virtually right now. Thanks for the help. I guess that I need to re-think my matl' spec for this part.

I'm trying to replace a part currently WireEDM'd in two dimensions from S7 tool steel and then HT to ~55-56 HRc. From my FEA of the current design I have found that the S7 is overkill.

We would like to go from a machining to a stamped part. The trouble is that to achive the strength levels that are required (YS~180ksi UTS >200ksi, Decent toughness) 1095 just really wont work. (we have some experience with stamping small, thick parts from 1095.) I looked in the Precision Steel book and found that 4130 is available in coil form at the gauge I need. However I forgot to check the hardenability curves (DOH!).

Does anyone have any suggestions? I'd like to specify the highest hardenability steel w/ good toughness that I can. From unclesyd's first post the 4130 at HRc of 49 might be exactly the ticket. (Though I'll look up oil quenching just to see if its possible to get similar strength levels w/ the less brutal quench.)

Of course the material I spec is going to have to be available in coil form at ~6mm thick and in the annealed or dead soft temper.

Thanks for the help. I plug those YS and UTS in and see ho close I am to the limits.

nick

 

[metengr]

NickE;
Try AISI Type 4340

 

[EdStainless]

4340, 4335V
These alloys harden nicely, and even though you don't need good thru hardening you will be able to take advantage of the better toughness at these strength levels.
I have used 4335V at 185UTS and 175yld and we had 15-20% for tensile elongations. You should have plenty of room.

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