Welded joints in a structure (e.g. a bridge) are expected to possess certain service-related capabilities.
Welded joints are generally required to carry loadings of various types in which the weld is subject to stress of either a simple or complex character.
It is therefore necessary to find out how satisfactory or sound the weld is.
For this purpose certain weld testing and inspection procedure have been discovered and standardized to estimate the expected performance of the welded structure.
WELD TESTING AND WELD INSPECTION
Testing specifically refers to the physical performance of operations (tests) to determine quantitative measure of certain properties such as mechanical which will be explained later.
(See article with title “Introduction on Mechanical Testing for WPS/PQR Qualification).
Inspection on the other hand, has to do with the observations of the processes and products of manufacture (e.g. weldments) to ensure the presences of desired qualities of properties.
Testing aims to determine quality, i.e. to discover facts regardless of the implications of the results, whereas inspection intends to control quality through the application of established criteria and involves the idea of rejection of substandard products.
STAGES OF WELD TESTING AND WELD INSPECTION
For fabricating a welded structure of EPCI Project for Oil & Gas Industry, Testing and Inspection may be carried out in below stages:
- Mechanical Testing for WPS/PQR Qualification
- Inspection before starting welding
- Inspection during fabrication by welding
- Inspection after the welding is over
- Re-inspect completed repairs