2 replies to this topic

[PME]

In refinery there is only two types of welding viz. socket welding for small bore (upto 1.5") & butt welding for large bore(>=2").Why fillet welding is not there ?

Regards
PME

[Art Montemayor]

PME:

What is your knowledge of welding and pipe fittings? Are you a certified welder? Have you ever welded steel?

The reason I am asking the above is that your question contradicts itself and, therefore, shows that you have an incorrect grasp of what you are asking. A fillet weld is what is applied to a socket type of fitting. A fillet is NOT A FULL PENETRATION WELD and, as such, is not very strong.

A full-penetration butt weld is inherently a full penetration weld and offers the strongest and most mechanically strong weld you can achieve on a joint. In some instances it has been shown to be STRONGER than the joint itself.

I have made butt welding mandatory on pipe joints as small as 1" in plants where I was using schedule 80 & 160. I seldom, if ever, employ socket joints or slip-ons. The fillet weld, in my opinion is restricted to low pressures and is not very strong - regardless of the pipe or joint size.

I recommend you obtain and study the various piping and welding books that are available throughout the Internet. Every engineer should have a reasonable knowledge of welding types and techniques.

[PME]

Thanks for your valuable comments.
Regards
PME