Calculating Minimum valve wall thickness

[Ryan_K]

Hello,

I am checking minimum wall thickness of ball valve body.
Normally, we use same thickness for stainless steel and carbon steel valve body.
However, in case of using Inconel, I am not sure if I can use thinner wall thickness considering higher strength of the material.

In ASME B16.34, minimum wall thickness of valve body is shown in table 3A or table 3B.
And calculation method is shown in Mandatory appendix VI.
But these tables and calculation method is not related to properties of different materials.
It means soft & hard materials will have same minimum wall thickness.

However, there is another calculation in ASME B16.34 Nonmandatory appendix B.
And this equation is related to stress based constant which is related to material properties.
By using this equation, we can see harder material needs less thickness.

In short, I am not sure whether I have to maintain same minimum wall thickness for all different materials or if I can use less minimum wall thickness for harder material based on equation in ASME B16.34 Nonmandatory appendix B.

Thank you.

 

[gerhardl]

You will find a lot of previous questions and answers using the search engine on top of this page. 'Search Posts' and 'valve wall thickness'.

 

[Ryan_K]

Thank you. I have searched all posts, but all say only about table 3 in ASME B16.34, and there is no information if we can use equation in ASME B16.34 Nonmandatory appendix B.
Surely, it table 3 is the most conservative value considering it is calculated with minimum tensile strength.
However, in case of using inconel, it seems that it is too much waste of material because the calculation result based on appendix B shows much smaller required thickness than value in table 3.