Metallurgical Compatibility
The two facets of property as above could be made analogous crudely to an athlete's wholesome strength, which includes both his physical fitness and stamina. A person's height, weight or chest x-ray can give an account of his physical fitness where as stamina is tested by a 'run'.
Similarly a radiography can give a conclusive account of the physical soundness of a weld but the metallurgical compatibility is revealed only by running mechanical tests; the result of this test being then named as mechanical property of the weldment.
Conversely, a welding procedure, which is written to specify the welding parameters in order to attain the metallurgical compatibility is qualified necessarily through a destructive mechanical test. The skill of the welder which directly influences the soundness of the deposit can be easily assessed or rather qualified through an x-ray evaluation.
Section IX of the ASME code, requiring' no bend test' (only in lieu of Radiography) and DIN 8560 not requiring minimum bending angles to be reached seem to be in line with this philosophy in the case of welders' performance test.