Are all Fillet Welded Pipes a TYK connection

By pipewelder_1999 (****)

Date 07-03-2009 14:09

In the scope of D1.1 is any connection to the end of a pipe that is fillet welded considered to be either a T Y or K connection. An example, would a flate plate welded on the end of a pipe be a T. Or a socket weld coupling etc.

I already have my own opinion and have nevery really thought that anyone would think otherwise. Just wanted some opinions.

Thanks

Gerald

By MBSims

Date 07-03-2009 14:49

My opinion is that it is not always a T-Y-K connection, even though D1.1 is not very clear on the subject. In reviewing D1.1, I noted the following definitions:

tubular connection. A connection in the portion of a
structure that contains two or more intersecting members,
at least one of which is a tubular member.

tubular joint. A joint in the interface created by a tubular
member intersecting another member (which may
or may not be tubular).

In Table 4.10, a welder qualified on a plate test may also weld PJP and fillet welds in either pipe or box tubes in T-, Y- or K-connections. So if you are fillet welding slotted tubular braces, fillet welding smaller box sections to larger box sections, welding size-on-size box sections with a combination of fillet and PJP flare bevel groove welds, etc. a 6GR welder qualification is not required.

By pipewelder_1999 (****)

Date 07-03-2009 15:16

The "Tubular Connection" definition is seems to support the idea that a T Y K connection need not be tube-tube. Then wouldn't any FILLET weld that attaches anything to pipe be considered a T Y or K connection ? I am speaking only in regards to fillet welds.

By MBSims

Date 07-04-2009 00:35

By the D1.1 definition - yes. I just don't believe it was their intent that the T-, Y- or K- requirements be applied when pipe or tube is only used as a convenient product form and the tubular member is not part of a structure that is made up of primarily tubular members. Why be "penalized" for a conservative design that uses HSS members as a brace instead of another shape? This would be a good inquiry for D1 if one does not already exist.