Posted by: heatsschoolofweldingtechnology | December 11, 2008

Welding Variables


In the world of welding, preparation of WPS and Qualification of Welders are very important. In the fabrication of any coded work such as structrual steel (which is under AWS D1.1 Code), Piping (under ANSI B31.1 or B31.3) Pipelines (under API 1104 or B31.8), Pressure Vessel (under ASME VIII Div.1), and Storage Tanks (under API 650), by right, you cannot start any welding works unless you have an approved WPS and a Qualified Welders.

In the preparation of WPS and Qualification of welders, there are welding variables that were stated in ASME IX. These welding variables plays an important role in the welding works.

We call these welding variables as AN ESSENTIAL VARIABLES, SUPPLEMENTAL ESSENTIAL VARIABLES, or NON ESSENTIAL VARIABLES. QW-250 of ASME IX refers to Procedure Qualification and QW-350 of ASME IX refers to Welder Performance.

QW-400 of ASME IX explains the above welding variables as follows;

  • Essential Variable (Procedure). A change in a welding condition which will affect the mechnaical properties (other than notch toughness) of the weldment (for example, change in P-number, welding process, filler metal, electrode, preheat or PWHT.
  • Essential Variable (Performance). A change in a welding condition which will affect the ability of a welder to deposit sound weld metal (such as a change in welding process, deletion of backing, electrode, F-number, technique, etc.
  • Supplemental Essential Variable (Procedure). A change in a welding condition which will affect the notch toughness properties of a weldment (for example, change in welding process, uphill or down vertical welding, heat input, preheat, PWHT, etc.)
  • Non Essential Variable (Procedure). A change in welding condition which will not affect the mechanical properties of a weldment (such as joint design, method of backgouging, or cleaning, etc.)
Advertisements

Responses

  1. […] Welding Variables « Heats School of Welding Technology Inc.Heats School of Welding Technology Inc. Romulo Higway, #4 Joanne Subd., Carangian, Tarlac City, Philippines. « Types of Guided Bend Tests Welding Variables. In the world of welding, preparation of WPS and Qualification of Welders are … […]

  2. good info. thanks.

  3. HI Michael,
    Thanks for visiting my blog and for your comment. I also have some stuff in the Q&A page.

  4. Its good to see a website regarding welding. I have a problem of excessive welding spatter while welding passenger car wheels, wherein we are facing during the usage of Ar-Co2 mix gas.

  5. Hi Mohan, thanks for coming by, the major problem of spatter are high current and damp electrode. rectify these two and try if you still have problem with it


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Categories

%d bloggers like this: