General question about hardening and tempering process

[tcwong]

To all,

I am in the process of evaluating the performance of an existing half hard tempered CRS bracket and I just realized that I don't have any information regarding the physical property of the material after the hardening process other than the hardness number. I know there is a relationship between BHN and UTS, but is there anything else? How about the yield strength? Would the Young's Modulus be affected in anyway?

Any help will be greatly appreciated.

Thomas Wong
Chicago

 

[metengr]

Knowing the material composition of the bracket, the answers to your questions can be found in a copy of the Metals Handbook, Desk Edition. Young's Modulus for metals is not affected by heat treatment.

 

[metman]

Thomas,
As metengr noted it depends on the material composition. I am not familiar with a designation half hard CRS but for example; As rolled 1018 (mild steel) YS is 45ksi and UTS is 67ksi at HB 137.

If you do not have access to metals handbook, go to the FAQ tab on this forum and you will find some links there that will provide info for your alloy.

Jesus is THE life,
Leonard

 

[stanweld]

Generally CRS (cold rolled sheet) steel has < 0.10% Carbon and may be ordered in various "tempers" depending on end use. In the case of steel CRS, this may mean an additional cold rolling operation after process annealing performed above the recrystallization temperature. Low process annealing temperatures coupled with higher reductions during temper rolling prduce higher strength materials.

Half hard is also a well known designation for aluminum and copper alloy cold rolled sheet.

Additional cold working increases YS and TS and reduces the YS to TS ratio.