Dear All,

As we know that

Expansion stress allowable Sa= 1.5(Sc+Sh)

=> Sa = 3/2 (Sc + Sh)------------(1)

As per ASME B 31.3 Code

Sc= min( 2/3 Sy or 1/3 Sut)
Sh= min( 2/3 Sy or 1/3 Sut)

If I substitue Sc and Sh values in EQ-1

then Sa= 3/2((2/3*Sy)+(2/3*Sy))
= 3/2(2/3(Sy+Sy))
=(Sy+Sy)
=2Sy

Means for Expansion stress we are going up to two times yield value. I dont think so. Some where I did a mistake.

Please Correct me.