ASME B31.3 Paragraph 302.3.2 (f) Question / Explanation Requested

[beh188]

Can someone help me to understand ASME B31.3 Paragraph 302.3.2 (f).

It reads:

"(f) Unlisted Materials. For a material which conforms
to para. 323.1.2, the tensile (yield) strength at temperature
shall be derived by multiplying the average
expected tensile (yield) strength at temperature by the
ratio of ST (SY) divided by the average expected tensile
(yield) strength at room temperature."

Specifically, I am not understanding the ratio part of this calculation. I cannot seem to work out a reasonable number.

 

[trottiey]

ST and SY are the minimum tensile and yield strengths permitted by your material specification. Any real-life sample of material that meets the specification will have greater strength. The "average expected strength" is the average from a bunch of real-life samples. Does that help?

 

[beh188]

I think I am getting it now. This paragraph is actually talking about two separate calculations (one for tensile and one for yield). Previously I did not realize this.

Tensile @ temp = (Tensile avg @ temp)*ST/(Tensile avg @ room temp)

&

Yield @ temp = (Yield avg @ temp)*SY/(Yield avg @ room temp)

 

[trottiey]

Correct.