Line-Magna (LM)

lm 01This system performs in-line surface flaw inspection of steel billet utilizing fluorescent magnetic particle testing method while the billet being transferred on the V-roller conveyor. All surfaces and corners of the billet is visually inspected and marked by inspectors for removal in the grinding process later.



  • In-line continuous inspection during the billet being transferred
  • Low equipment cost, less installation space
  • Flaw inspection can be done by two inspectors. This is less than one half compared to required number of inspector of Axial electric current magnetization method.
  • Detecting longitudinal, transverse and corner defects simultaneously
Main Specification
Type of steel to be inspected Carbon steel, Low alloy steel and Special steel
Dimension Square billet 120-160 mm sq.
Billet transfer speed Max. 15 m/min. (V-roller transfer)
Magnetizing method Combined magnetization with Yoke coils and Ring coil
MPT material Fluorescent magnetic particle suspension
Defects to be detected Surface breaking natural flaws (crack, scab etc.)
Detecting accuracy Longitudinal flaw (crack): more than 0.3 D x 10 L mm
Transverse flaw (scab) : more than 0.3 D x 10 dia. mm
Electric power AC 400/440 V±10%, 3-phase, approx. 150 KVA
Air More than 0.4 MPa, 5.0 Nm3/min.
Normal consumption : approx. 0.8 m3/min.
Water Service water 100 L/min.


Main Equipment
Suspension spraying equipment Suspension spray nozzles
Magnetizing equipment (4 sets of Yoke coils and one Ring coil) x 2 sets
Suspension tank 500 L tank with circulation pump
UV light Super-Light E-40-2 x 8 sets, Mirror units
Control equipment Control panel, Magnetizing power source panels, Local operation panel

Inspection Procedure

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