Cheatography
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For the purpose of calibrating Mag Control instruments prior to inspection suitable calibration plates are required.
This is a draft cheat sheet. It is a work in progress and is not finished yet.
General
Wall Thickness |
The plate, coupon or pipe wall thickness needs to be the same as compared to the inspection object |
Wall Thickness Deviation |
Deviations of up to 10% wall thickness are permissible |
Lift-off Height |
The lift-off needs to be representative of the actual inspection scenario |
Defect Set
Sizes of Defects |
For regular calibration two diameter sizes of defects are required, typically in the range of 1 and 2 times the sensor diameter |
Set Calibration |
For each set calibration data should be obtained in far-side and near-side configuration. If the calibration piece is curved, it is required to produce the sets separately internally and externally. |
Depth Calibration |
From 20% to 80% |
Minimal Set Defects |
Four. One through-hole defect should be present, preferably of the smaller diameter |
Defect Positioning
Defects Separation |
150 mm (from edge to edge) |
Defects Separation (F15, P19, MPS200) |
200 mm (from edge to edge) |
Regular Lift-off |
<10mm |
Machining
It is preferable if the defects are machined with EDM (Electric Discharge Machining) |
If mechanical machining is used, it should be ensured, that the metal is sufficiently cooled and the drill bit is sharp, such that no excessive forces are used to cut into the metal |
Defects Profile
Flat bottom defects can also be used and may in some cases be required by norm.If the radius cannot be machined, because the required tools (bits) are not available, it is more important to keep the defect diameter and use a different depth
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