True Temper's VERUS Stress Relieved 4130 steel is designed for reliability that is even better than commercial grade 4130. This heat treatment removes internal stresses left over from the manufacturing process. The end result of removing internal stresses is that the tube (and your frame) lasts much longer. [Why: click here]
The trade off for increased strength in ANY material is decreased ductility. The real world result is that the failure mode gradually changes from controlled gradual bending to instant catastrophic fracture. Heat treatment can vary the strength of 4130 steel from a very ductile 70,000 psi up to a hard and brittle 225,000 psi. At 100,00 psi, Stress Relieved 4130 is a very reliable material with optimized properties for bicycle use.
But, you say, having absorbed all the hype, "Doesn't low strength mean high weight?" Not necessarily. It turns out that, by the time you make a steel bike stiff enough that it feels great, you have used enough steel in the tube walls to lower the stresses to where you don't need a high strength steel to withstand the loads and still have a good safety factor.
For these reasons, True Temper uses Stress Relieved 4130 steel for the general purpose VERUS main triangle tubing, seat stays and chain stays, and its fork blades.
True Temper's VERUS HT Series tubing is made possible by True Temper's decades of experience in the heat treatment of 4130 steels for maximum performance. As steels are strengthened by heat treatment, the ductility is reduced. If you were to heat treat 4130 steel as hard as possible, the tensile strength would go all the way up to 255,000 psi. But the steel would very brittle and subject to failure by fracture, making it unsuitable for bike frames. The metallurgists at True Temper designed the VERUS HT heat treatment to reach the high level of 175,000psi., while still maintaining good ductility.
VERUS HT is also available at 150,000 psi tensile strength, midway in strength between True Temper's 110,000 psi Stress Relieved VERUS steel, and their 175,000 psi VERUS HT steel tubing. Naturally, frame builders use this tubing when they want characteristics between these two strengths of steels. This VERUS HT maintains the workability of the stress relieved VERUS, and approaches the strength of the VERUS HT Special Heat Treat.
http://www.henryjames.com/verusht.html
Chrome moly which in its generic state should carry a SAE/AISI number 4130 will in the best case scenario have a tensile strength of 80,000 psi., before welding. These values are for 4130 produced by a reputable steel manufacturer. Generic “Chromoly” supplied by an unnamed source or imported oriental steel should be looked upon with a great bit of skepticism.
http://www.worldclasscycles.com/JACKSON-HOME.htm
Reynolds 631 - cold drawn
UTS: 52 - 58 Tsi, 115 - 130 Ksi,
800 - 900 MPa
Following on from the success of 853, Reynolds have added 631 to the range of AIR HARDENING STEEL tube sets. This seamless cold drawn steel tube will allow the benefits of this new steel to be used in the manufacture of a wide range of frames and is now considered a worthy successor to our legendary 531 tubing. Like 853 it is suitable for TIG welding and brazing and in the heat affected joint areas will gain strength, to ultimate tensile strengths in excess of heat treated chrome molybdenum. The strength to weight ratio of 631 is equal to that of many aluminium frames, and it has an excellent fatigue life whilst providing a supple ride quality suitable for long distance events.
On road and touring frames we suggest 631 or 525 forks be used in conjunction with 631 frames. As 631 is only available in main frame tube sizes, we recommend the use of either heat treated CrMo (725) or cold drawn CrMo (525) seatstays and chainstays to complete the frame.
http://www.worldclasscycles.com/reynolds_631.htm
http://www.columbustubi.com/pdf/Steel_tubes.pdf
http://www.reynoldsusa.com/english.html
http://www.truetemper.com/performance_tubing/tubing.asp
http://www.dedacciai.com/home_eng.html
http://www.eaa1000.av.org/technicl/4130.htm
http://www.suppliersonline.com/propertypages/4130.asp
Just in case anyone is having trouble sleeping at night.