Conventional CRGO grades generally M3,M4,M5 and M6 are used regularly for Lamination cores in Transformers. However recently due to environmental protection, energy savings are becoming a very important factor and minimizing core loss in Transformers is becoming a must. Nippon Steel Corporation and other CRGO producing mills has come out with low loss Hi-B materials, which guarantee low Watt Losses at 1.5 Tesla flux density. Such materials are called Hi-B materials. Above table gives magnetic properties of Hi-B material. Popular CRGO Hi-B grades used are 23 MOH & 27 MOH.
Important physical properties of CRGO | |
Density gm/c3 | 7.65 |
Silicon content % | 3.10 |
Resistivity micro Ohm-centimeter | 48.00 |
Ultimate Tensile Strength 0° to Rolling Direction Kg/mm2 | 32.60 |
Ultimate Tensile Strength 90° to Rolling Direction Kg/mm2 | 38.20 |
Stacking factor % M4 (.27 mm) | 96.00 |
Stacking factor % M5 (.30 mm) | 96.50 |
Stacking factor % M6 (.35 mm) | 97.00 |
CRGO materials come either in the form of coils or sheets. Given below the details of CRGO dimensions and tolerances as per JIS C 3553. |
CRGO COILS | Thickness | 0.18 mm (0.0071 in. ) |
0.20 mm (0.0079 in.), 0.23 mm (0.0091 in. ) | ||
0.27 mm (0.0106 in.), 0.30 mm (0.0118 in. ) | ||
0.35 mm (0.0138 in.) | ||
Width (Standard width available with range) |
914 mm (36 in.), and 1000 mm (39 in. ) | |
from 50 mm(2 in.), to 1.050mm (41 in. ) | ||
Inside Coil Diameter
|
508 mm (20 in. ) | |
Sheets | Thickness | 0.30 mm (0.0118 in.), 0.35 mm (0.0138 in. ) |
Width | 914 mm (36 in.), and 1000 mm (39 in. ) | |
Length | Length will be available according to negotiation |
conform to JIS C 2553.
Width mm |
Thickness mm | TOLERANCE | ||||
Thickness mm |
Deviation of thickness
in transverse direction mm |
Width mm |
Camber in any 2 metres (Slit Products) mm |
Shear Burr mm | ||
150 or under |
0.18 0.20 0.23 0.27 0.30 0.35 |
+0.02 +0.02 +0.02 +0.03 +0.03 +0.03 |
0.02 or under
|
+0.20 | 1.0 or under |
0.04 or under |
over 150 to 400 |
0.18 0.20 0.23 0.27 0.30 0.35 |
+0.02
+0.02 +0.02 +0.03 +0.03 +0.03 |
0.02 or under |
+0.30 | ||
over 400 to 750 |
0.18 0.20 0.23 0.27 0.30 0.35 |
+0.02 +0.02 +0.02 +0.03 +0.03 +0.03 |
0.03 or under |
+0.50 | ||
over 750 | 0.18 0.20 0.23 0.27 0.30 0.35 |
+0.02 +0.02 +0.02 +0.03 +0.03 +0.03 |
0.03 or under |
+0.6 0 | ||
Note : Stipulation of camber shall be applied only for the steel strips (width 75mm over). |