photo
Electrical Steels
CRNO Coils and Sheets
To meet the demands of the electrical industry, Rourkela Steel Plant offers Cold Rolled Non Oriented (CRNO) fully processed steel used in the
manufacture of magnetic cores and components.

Standard Width : The standard width of CRNO coils or sheets are 900, 950 and 1000 mm. Slit coils can be supplied in minimum width of
100 mm and then in multiples of 10 mm. Other sizes are negotiable.

Standard Length : The standard length of CRNO sheets are 2000 and 2500 mm.

Coil Weight : 1 to 5 tonnes.

Electrical Steel
Flatness %: (Wave height/Wave length) x 100
Burr height : maximum 50 micron
Grades and Specifications
Magnetic and Mechanical Properties
CRNO steels from RSP are graded on the basis of Epstein Core Loss Test at magnetic induction of 1.5 Tesla. The maximum core loss limit is based upon the general procedure established by the Indian standard for testing (IS 649). For this purpose RSP has set up a fully equipped and modern testing laboratory consisting of among other equipment, a sophisticated Digital Core Loss Testing Unit. Other test instruments include Franklin Surface Insulation Resistance Tester, Hay Bridge, DC Hysteresis Loop Tracer etc.

Magnetic properties and lamination factor of SAIL CRNO coils/sheets are in conformity with IS: 648 (BIS) specification.
Note : The present production range is in 0.50 mm thickness.
Equivalent to IS 640: 2006
photo
Electrical Steels
The values are measured in accordance with IS 648 methods using as sheared specifications consisting of half of the strip parallel and half sheared transverse to the rolling directions.

Magnetic Ageing : The Non-Oriented steels will have less than 5% increase in core loss upon a standard ageing treatment (at 2250C for 24 hours). Grading is done based on watt loss value obtained after ageing.

Packing : The material is first wrapped in stretch film over card board protectors in the eye and OD edges followed by an additional layer of air-bubble polythene type covering. It is then packed in galvanised sheet metal envelope. Metallic collars are provided in the eye of the coil and on the OD to prevent handling damages. The envelope with strapped with 4 eye and 3 to 4 circumferential straps. Additional support is provided when warranted. No metallic packing is given on slit coil.

Insulation and Applications