Welding is an engineering process that joins components or parts of similar or dissimilar compatible materials
This is often done by melting the joining interfaces of the objects and adding a filler material to form a pool of molten material which forms a permanent joint after solidification.
The most common welding process are MMAW, SMAW, GMAW, GTAW, PAW, SAW, FCAW, Oxygen-Fuel Welding, Resistance spot and seam weld, Thermit weld, Explosion weld, flash welding. There are numerous variables in these processes when uncontrolled can contribute to inadequate or unacceptable weld joint. As a standard practice, a weld sample is produced prior to commencing the final welding of the product. All welding variables are controlled and recorded when welding the weld sample or coupon.
These welded coupons are then tested to ensure that the weld joint will be of acceptable quality. The welded sample or coupon is often tested at various stages of fabrication such as for Welding Procedure Qualification Record (WPQR), to qualify Welding Procedure Specification (WPS), to qualify welder as Welder Qualification Record ( WQ or WQR) and to accept the final product in the form of Production Weld test.
IDTL provides the following two services:
- Procedure Qualification (PQR)
- Performance Qualification (WPR)
They are technical control, test, assessment and approval services conducted with the purpose of certifying the compliance of purchased / ordered product and/or services or plant to the international standard, code and customer technical specifications during and/ or after manufacturing.