ISO 11970:2016 specifies how a welding procedure specification (WPS) for production welding of steel castings is qualified. It defines the conditions for the execution of welding procedure qualification tests and the limits of validity of a qualified welding procedure for all practical welding operations within the range of essential variables. Tests are intended to be carried out in accordance with this International Standard unless additional tests are specified by the purchaser or by agreement between the contracting parties. ISO 11970:2016 applies to the arc welding of steel castings. The principles of this International Standard can be applied to other fusion welding processes subject to agreement between the contracting parties. In the case of specific service, material or manufacturing conditions, tests more comprehensive than those specified by this International Standard can be specified by the purchaser, in order to gain more information, e.g. longitudinal weld tensile tests, bend tests, chemical analyses, ferrite determination in austenitic stainless steels, elongation, Charpy "V" impact tests, and radiography.