AWS A4.2M:2020 pdf free download

AWS A4.2M:2020 pdf free download.Standard Procedures for Calibrating Magnetic Instruments to Measure the Delta Ferrite Content of Austenitic and Duplex Ferritic-Austenitic Stainless Steel Weld Metal.
7. Other Methods
7.1 Methods. Methods for determining ferrite content other than through the evaluation of attractive force or methods differing from that described in this standard may be used, such as volumetric determination by magnetic saturation, provided that they have been calibrated by secondary standards in which the ferrite content has been determined by the method described in this standard. Secondary standards can be prepared using the method specified in 5.1 and 5.2, by assigning to them FN values by the method specified in 5.3.
NOTE: Secondary 11W standards, prepared in accordance with Annex A were previously produced by TWI (The
Welding Institute) in the United Kin gdom. Secondary 11W standards, prepared in accordance with Annex B, (ire
available from the National institute of Standards and Technology (NIST, Office of Reference Materials in the
USA (https://www nist. gov/srm).
7.2 Results. The results obtained by methods other than the method described in this standard, even if calibrated in accordance with 7.1, may, under certain circumstances, differ from those obtained by the method described in this standard. Hence, in cases of dispute, the method described in this standard shall be used.
On a given specimen, the average FN as determined by other methods and compared with measurements obtained with the method described in this standard, shall be within a tolerance band of ± I FN in the FN range up to 10 FN and this may be proportionally higher as the FN increases beyond 10 FN.
7.3 Maintaining Calibration. Instruments shall be checked periodically against secondary standards or primary standards. It is therefore recommended that the organization which uses the instrument ensure that a set of standards be available. It is the responsibility of the user to see that the frequency of checking is adequate to maintain calibration. One standard shall he used for each ot the ranges (see Table 3) for which the instrument is to he used. The average value of five measurements at individual positions on the standard shall be within the maximum deviations specified in Table 3.AWS A4.2M:2020 pdf free download.