UCS-79(d)(5) request

[ChiangJaron]

All expert,

UCS-79(d)(5) specified rule "The temperature of the material during forming is
in the range of 250°F to 900°F (120°C to 480°C)."

Why the rule shecified a temperature range, not a limit temperature ?

If the head form is formed belowing 119°C, could I exempt the heat treatment based on this rule ?

 

[Don56]

I can't answer your first question, but as to the second question. If your material is P1 material, and the fiber elongation is less than 40% and none of the other constraints of UCS-79(d)apply the answer is yes.

 

[metengr]

The reason for the temperature range is that this is considered the warm forming range for carbon steel. It is not high enough in temperature to reduce forming strains but does drop the yield strength to enable forming with lower forces.

This is only one of 5 requirements which you must comply if you have P-No 1 material with only
5 % extreme fiber elongation. Go back and re-read this section

.....For P-No. 1, Group Nos. 1 and 2, this
subsequent heat treatment is required when the extreme
fiber elongation exceeds 40%, or if the extreme fiber elongation
exceeds 5% and any of the following conditions
exist

So, if you have 5% extreme fiber elongation AND any of the (1)-(5) requirements are met, you must heat treat after forming. If you met none of the 5 requirements, the extreme fiber cannot exceed 40% for P-No 1, Groups 1 and 2 base materials.