Q. Check ferrite content of austenitic stainless steel weld?
Check the ferrite content of each austenitic stainless steel weld, including overlay welds, in the as-welded condition using a Severn gauge or a Feritscope. The ferrite shall be between three and ten percent (3-10 FN).
Ferrite number shall be determined over the complete range of applicable welding parameters specified in the WPS.
Ferrite test shall be performed on all austenitic stainless steel.
Frequency of testing shall be as follows:
• For overlaid components two tests shall be made on each component.
• For clad restoration one test shall be made for each 3.05 m (10 ft) length.
X-ray fluorescent analyzer or wet analysis methods shall be used to verify chemistry of components and welds.
Testing shall be performed to recognized standards by an approved testing agency or laboratory.
Magnetic instrument used to measure the delta ferrite content of austenitic stainless steel weld metal shall be calibrated per AWS A 4.2, latest edition.
Type 310 welds are exempt form this requirement.