So you have completed your weld and want to demonstrate your welded component. How do you do that? Using a Weld Map.
What exactly are weld maps?
A Weld map is a critical component of a welding project which gives information about the design of the weld, quality, and location of each weld.
And the process of assigning the information to a weld is known as weld mapping.
Weld mapping is also sometimes called weld tracking or welding traceability and is usually confused with fabrication drawings. As a matter of fact, both of those are separate components of the metal fabrication process.
Components of a Weld Map
A weld map is laid out based on the two following features.
WPS or Welding procedure Specifications
These are procedure specifications of the weld issued to the customer by the manufacturer which contains information about necessary parameters like types of joints, filler metal, characteristics and techniques to be used for welding, etc.
The ASME (American Society of Mechanical Engineers) has set these parameters and are known as variables.
According to the ASME, there are 3 types of variables
Essential Variable – For mechanical properties of the joint apart from its toughness.
Non-Essential Variable – It doesn’t affect weld and changes can be made without the requalification of the WPS.
Supplementary Essential Variable – For toughness of the joint.
After the WPS is submitted, a customer welding SME( Subject matter expert) goes through it and comments or approves them. This is to ensure the maximum quality of the weld.
Sometimes the biopharmaceutical industry needs their welding done. In this industry, these are used primarily for fluid transfer and carrying their products from one place to another.
PQR or procedure qualification record
A PQR documents particularly the essential variables and all the additional details which are recorded during the testing phase.
The test done on the weld either can be an NDT(Non-Destructive Testing) like visual inspection, electromagnetic testing, leak testing, etc, or Destructive Testing like a Bend test, Corrosion Test, Embrittlement, etc.
After the recording of the testing is done by a welding engineer, it is then reviewed by a TPI( Third Party Inspector) who checks up on the test results and overall procedure of the weld.
The TPI is not required always and depends upon the customer requirements. Usually, huge projects require multiple TPIs.
Weld Map Software
As the technology and innovation expanded in the welding field, it introduced a wide range of products and one of them is a weld map software.
This software requires minimal effort to make a map and sometimes helps with creating pictorial weld maps. The joints and other important variables can be marked with ease.
However, some welders still stick to the way of drawing a well-labeled map on their own. And as the only disadvantage, you are locked up in the method in which the software was programmed.
Some experienced welders even go on to develop a weld documentation system that does exactly what they want. Only a small portion of the welding community resort to this method though.
Some of the Popular Weld Map Softwares:
- Smart welding manager
- Microsoft Visio
- Turbo CAD
Weld Map Example
Let’s take a look at this weld map sample of a pressure vessel.
WPS 01 – This will be used for circumferential and longitudinal joints.
WPS 02 – The second type of weld requires another procedure to weld as the those are the heads of the vessel having a varied thickness, thus WPS 01 cannot be used due to thickness range limitation.
WPS 03 – The boot weld is done with the help of WPS 03 as the vessel material is mainly carbon steel whereas the boot material is stainless steel. The difference in material leads to another type of welding procedure.
The image shows a pictorial format of a weld map, however, they can be even displayed in a table. Some prefers to use the pictorial format while others use the latter one.
Sometimes, welding projects are huge and may require a large number of WPS(Weld Procedure Specification).
Displaying a weld map in pictorial format is not the preferable option in those circumstances.
Sometimes, welding cameras are used to record the weld process to find any problems occurred during the process.
Since there is no standard way of making a weld map, it solely depends on personal opinion. Each manufacturer or welder has their way of displaying a weld map.
In the testing phase of a weld joint, the weld inspector with the help of the weld map examines it. Various tests are done to ensure that the weld has no issues.
After the inspection, the inspector logs whether each weld has passed a visual boroscope examination along with his signature and date in the weld log.
Essentially the main body has 9 columns for the weld and 3 columns for the weld inspector.
I hope you have cleared all the queries you had in mind before reading about weld maps and weld logs.
This ultimately tells use how important documentation really is for a welding project.
Weld maps act like a checklist, which the inspector goes through and matches with the weld. Ensuring that the weld meets all required standards and regulations.