Examination of welds to determine characteristics such as ductility, soundness, tensile properties, hardness, fracture toughness, fatigue properties of welded structural joints, corrosion factors, or behavior at elevated temperature.

The two main types of testing are destructive and nondestructive. Tensile testing, or loading in tension until failure occurs, is an example of destructive testing. Visual inspection is an example of nondestructive testing.

The ideal test would be to observe the structure in actual service, but this is rarely practical. Therefore, standardized tests and testing procedures are used that give results which can be related to metals and structures that have performed satisfactorily in service. Reference is frequently made to ANSVAWS B4.0, Standard Methods for Mechanical Testing of Welds.

The problem of predicting the performance of structures from a laboratory-type test is a complex one, because the size, configuration, environment, and type of loading in service usually differ.

In welded joints, the complexity is further increased by the nature of the joint which is both metallurgically and chemically heterogeneous. In addition to the unaffected base metal, the welded joint consists of weld metal and a heat-affected zone. Those regions are composed of a multitude of metallurgical stfllctures as well as chemical heterogeneities, so a variety of properties can be expected throughout the welded joint.

Various testing methods are regularly used to evaluate the expected performance of welded joints. The property being tested, the test methods which may be used, and the application of results with special consideration of their relationship to welded joints are covered in the Welding Handbook, 8th Edition, Volume 1, Chapter 12; American Welding Society, Miami, Florida; 1987.

Among the various types of tests are pressure testing, bend test, compression testing, crushing, drift, fatigue, hydrostatic test, impact test, tensile, tube, visual testing, free bend test, magnetic testing, and x-ray testing.