Originally Posted by
Scooper
So no, they're not the same. 725 (heat treated) is different from non-heat treated 525 chromoly. It's similar to comparing heat treated 853 to non-heat treated 631 even though they have the same chemistry.
That seems to be true, whereas Reynolds appears to identify their tubing by both alloy and final condition to a unique number, however, 4130 is still the same material alloy, regardless. The condition is usually referenced after the alloy type such as 4130 annealed, 4130 normalized, or for heat treated 4130-XXX KSI or XX Hardness.
For reference:
The Reynolds 725 appears to be the very similar at 4130 150KSI.
The Reynolds 525 appears to be similar to 4130 SR (Stress Relieved) but without hardening (austentizing/quench & temper).
‘bob