The tensile strength for 1045 TGP Precision Steel Round is said to be 91 ksi. Although, different diameters must be a factor, right? Would a 1" diameter rod be 104.5 ksi or 1045 ksi?

Say I want to make a seven foot barbell, requiring about 150 ksi. Is it possible to get there by hardening some sort of steel? Or will that make it too brittle for lifting weight plates?

  • $\begingroup$ Hi adamaero, welcome to Engineering. Strength is expressed in ksi but the Force that can be carried by a different diameter changes. Also, when loading a barbell, the load is in bending, so its probably best if you provide what is the maximum load you want to put on the barbell, and then determine the minimum diameter. Finally, the steel you have in mind is already hardened. $\endgroup$ – NMech Oct 10 '20 at 15:47
  • $\begingroup$ The diameter is fixed at one inch. The recommended psi for barbells is 150 ksi. $\endgroup$ – adamaero Oct 10 '20 at 15:53
  • $\begingroup$ would you mind provide a reference/url link to that recommendation? $\endgroup$ – NMech Oct 10 '20 at 16:03
  • $\begingroup$ A strength of 150 ksi would be about the same as a good quench and temper hardened wrench; That seems very strong for a barbell . $\endgroup$ – blacksmith37 Oct 10 '20 at 17:58
  • $\begingroup$ @blacksmith no argument about the ksi and the heat treatments you state, however I can't get my head around why is that so important on a barbell? I mean, when talking about strength in this context, I would be more worried regarding what is the diameter of the barbell in order to not yield from the maximum weight on the barbell... $\endgroup$ – NMech Oct 11 '20 at 5:51

The data sheet says it has a 71ksi yield, I see no reason to doubt it. Cold drawn is likely stronger near the surface which would be an advantage for bending resistance. SAE 1045 means it means it is carbon steel with 0.45 %carbon. The primary feature or the material you list is a precision dimension surface . It will have low toughness but I can't imagine toughness is needed for a bar bell bar. It is roughly half the 150,000 psi strength you say you want. Addenda; I think the practical source is weight equipment vendors. Looking on the net I find high strength bar is a custom order type product; easy enough to find and heat-treat but in quantity like a ton plus. There is a product named "stress proof " bar that is close , SAE 1144 ,a cold worked free machining steel with about 0.44 % carbon. It may also not be easy to get in a small quantity.

  • $\begingroup$ My primary question is if it's possible to make a strong enough 1" diameter barbell on one's own, DIY. It appears it is not possible because of the lower tensile and yield strengths compared to professionally manufactured barbells. $\endgroup$ – adamaero Oct 14 '20 at 16:51

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