ISO 17635:2003 gives guidance on the selection of method(s) for non-destructive testing of fusion welds in metallic materials based on material, weld thickness, welding process, quality control requirements and extent of testing. It specifies standards to be applied to the different types of testing and general rules for either the methodology or the acceptance level for metallic materials. The test methods may be used alone or in combination. ISO 17635:2003 also gives guidance on evaluation of the results of non-destructive testing for quality control purposes based on material, weld thickness, welding process, quality requirements application and extent of testing. ISO 17635:2003 addresses non-destructive testing of completed welds. Examination and testing of parent materials prior to welding or between welding sequences is not covered.