Re: Dissimilar Piping Materials

From: <Christopher>
Date: Tue Jun 12 2001 - 10:53:00 EDT

>How does one handle the displacement stresses for a welded joint of
>dissimilar metals (straight pipe)?

Depends on what you mean by dissimilar. If you're talking about austenitic steel and carbon steel, they're not all that dissimilar, and the dissimilarities impact the welding procedures more than anything. Plenty of welding procedures for doing this which address possible corrosion and metallurgical issues.

If you're talking about really dissimilar metals with different elastic moduli and temperature coefficients, there's the possibility of high thermal stress (in addition to weld procedure problems). For simple cases, say a connection between two dissimilar pipes or stainless fasteners in aluminum, you can figure the thermal stress with classic manual stress analysis. If it's complex stuff with lots of temperature variations, FEA is usually more cost-effective than hand calculations.

Christopher Wright P.E. |"They couldn't hit an elephant from <a href="/group/PipingDesign/post?postID=8ePQcsK8YRz7-q4xOzH_2tEolmOOhO8g2gZQcSIh_m_KtakKIWgXO67iMXJ9NEhQoVCHxHjeYKnSZGLC">chrisw@skypoint.com</a> | this distance" (last words of Gen.

___________________________| John Sedgwick, Spotsylvania 1864)

<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a> Received on Tue Jun 12 10:53:00 2001