Lap Welds 2

[Agnewt]

My question is this: At what point, if ever, does a lap weld become a fillet weld?

It is my understanding that a 'lap' is a type of JOINT, not a type of WELD. A 'fillet' is a WELD, not a JOINT. A fillet WELD is used to join either a tee or lap JOINT.

It would also follow that the term "lap weld" would technically be inaccurate.

I ask because i would like to weld a slip-on flange onto a length of 24" pipe, however the buyer spec contains the following clause, word for word: "LAP WELDS are not permitted."

 

[MintJulep]

I agree with your interpretation.

However, take a look at faq403-1308

 

[JoeTank]

Technically correct or not, everyone knows what is meant by a lap weld or a butt weld.

Joe Tank

 

[hogan666]

AWS A2.4 defines both lap joint and fillet weld. It sounds like your connection can be detailed as a fillet.

 

[strider6]

"The butt joint includes a groove weld while the lap joints use fillet welds"
this is taken from this article of Lincoln foundation, i yhink that your interpretations is correct.

Designing Welded Lap Joints

http://www.jflf.org/pdfs/papers/design_file301.pdf

In my opinion the buyer spec use a incorrect welding terminology, it should be"lap joint are not permitted" or "fillet weld are not permitted".

S

Corrosion Prevention & Corrosion Control

 

[doct9960]

Agnewt,

When in doubt, ASK the buyer. The clause, "LAP WELDS are not permitted", may not even apply to your flange to pipe joint. The buyer probably intended that clause for longitudinal or circumferential weld joints on pipes, shells, heads or caps; and not on corner joints (slip-ons).

 

[pipewelder1999]

Lap joints may also contain groove welds. Though it is an uncommon practice it can occur.

I strongly agree that the referring to "Lap Welds" is incorrect and misleading.

Also, in my opinion a slip on flange is a lap joint so your desire to use a slip on flange may be prohibited by the interpretation that the "Lap Welds" are referring to "Lap Joints". That would also prohibit you from using any socket welded coupling.

I think clarification is needed from the specifier.



Gerald Austin
Iuka, Mississippi

http://www.weldingdata.com