Type of welds

There are basically 2 kind of welds, groove and fillet; this are aproved in AWS D1.1 in section 2.3. Groove welds are shown below:

From the site "Weldguru".

And this joint can also be divided in two cathegories, complete penetration (CJP) and partial penetration (PJP) . PJP is standarized in part 2.3.3.1 of the code and CJP in part 2.3.4. The difference between them is the penetration, wich is well understood in the words complete and partial.- 

Fillet welds are standirezed in section 2.4 of the code and they look like this:

From Unified Eng. Inc.

And below we can see a recent picture taken at a petroleum tank farm construction.

Below we can apreciate a preparation for a fillet weld for the floor of a tank acording to API.-

And a very important aspect of fillet welds can be to determine the maximum size of it, this can be found in 2.4.5 and figure 2.1 as seen below:

Details for Prequalified Fillet Welds. (See 2.4.5)