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Elcometer 111-7F鐵素體檢測儀 The Elcometer 111-7F is a hand-held magnetic gauge for checking the delta ferrite content in stainless steel weld bl. It is pre-calibrated and simple to use. The readings are in Ferrite Number (FN) in accordance with WRC and IIW recommendations. Operation Place the nose of the gauge onto the weld bl and rest the middle of the gauge on adjacent parent bl. Turn the central wheel to the zero end of the scale, now turn it in the opposite direction until the magnet clicks off. Read the value. What is Ferrite? A minimum ferrite content in austenitic stainless steel weld bl prevents microfissures and hot cracks. Too much ferrite can lead to corrosion or embrittlement at high temperatures. It is a magnetic material in an essentially non-magnetic bl and so can be measured by the force of attrb due to a magnet. Ferrite Number After much testing around the world, it has been decided that it is impossible to determine accuraby the true ferrite content of stainless steel weld bls. Previous figures of percentage content were very dependent on their source, the measuring instrument used ands its calibration. So Ferrite Numbers were established to define ferrite quantity and are related to the ferrite quantity of an equivalently magnetic weld bl Calibration The calibration of a gauge is such that the ferrite reading can be related to the seperation of the gauge's magnet from low carbon mild steel plate. The primary standard is thickness and the secondary standard is ferrite samples, and the Calibration Certificate supplied with the Elcometer 111-7F relates the gauge reading to both standards. Elcometer 111-7F Ferrite Indicator
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