Because Table A-1 is not given in metric - you must determine the imperial numbers and then convert.

47°C = 116.6°F

All B31.3 316L Tube/Pipe have an allowable stress of 16,700 psi from 100 to 300°F (no need to interpolate)

Therefore allowable stress at 47°C = 16,700 psi = 115 MPa

(It would appear that your colleague is wrong, or something has been interpreted wrong)

Thanks for your quick reply.

You're right but I still not understand how this guy do like that:

The equation is: (((PD) / (2*((SE) + (PY))))+ 1) * 1.125

= (((0.15*168.3) / (2*((290*1) + (0.15*0.4))))+ 1) * 1.125 = 1.17

The result is 1.17 but if S=115 MPa, we will get the result 1.25.

By the way, we have the equation: t_m=t+C but I wonder why this guy take the factor ''1.125'' in above equation??

It looks like you are trying to calculate the wall thickness for a straight length of pipe, where the equation is:

I am a little confused as to the the addition of '1' in your equation, and of your units - GPa, MPa, & mm? (I am used to imperial). [could the '1' be for corrosion allowance?]

However, I can say with some confidence that the factor of '1.125' is to allow for the manufacturers tolerance on wall thickness.

For an explanation see:

http://cr4.globalspec.com/thread/38586/mill-tollerence-in-pipe-material

Thanks your answer. I really appreciate that. How's useful to me!

I got it....

Thank you!