Welding Inspection & Metallurgy API ICP Self Study Notes

10.9.2 Weldability Testing
One of the best means to determine weldability of a metal or combination of
metals is to perform direct weldability testing. Direct tests for weldability are
defined as those tests that specify welding as an essential feature of the test
specimen. Weldability testing provides a measure of the changes induced by
welding in a specified steel property and to evaluate the expected
performance of welded joints. The problem with predicting the performance of
structures or welded equipment from a laboratory type test is a complex one
since size, configuration, environment and type of loading normally differ. For
this reason, no single test can be expected to measure all of the aspects of a
property as complex as weldability and most weldments are evaluated by
several tests. If tests are to be useful in connection with fabrication, they
should be designed to measure the susceptibility of the weld metal-base
metal system to such defects as (1) weld metal or base metal cracks, (2)
lamellar tearing 层 状 撕 裂 , and (3) porosity or (4) inclusions under realistic and
properly controlled conditions of welding. Selection of a test method may also
have to balance time and cost for emergency repairs or shutdown work.