规定了许多商用仪器的校准程序，这些仪器可以提供奥氏体不锈钢焊缝金属铁素体含量的可重复测量值。其中某些仪器可以进一步校准，以测量双相铁素体-奥氏体不锈钢焊缝金属的铁素体含量。使用初级标准（美国国家标准与技术研究所的非磁性涂层厚度标准）校准是适用于适当仪器的首选方法。或者，这些仪器和其他仪器可以使用焊接金属（如二级标准）进行校准。规定了校准后测量的再现性。 描述了与铁素体含量的精确测定相关的问题。

Calibration procedures are specified for a number of commercial instruments that can then provide reproducible measurements of the ferrite content of austenitic stainless steel weld metals. Certain of these instruments can be further calibrated for measurements of the ferrite content of duplex ferritic-austenitic stainless steel weld metals. Calibration with primary standards (nonmagnetic coating thickness standards from the U.S. National Institute of Standards and Technology) is the preferred method for appropriate instruments. Alternatively, these and other instruments can be calibrated with weld-metal-like secondary standards. Reproducibility of measurement after calibration is specified. Problems associated with accurate determination of ferrite content are described.