Silicon steel
1.0 scope
1.1 this specification covers the grain oriented electrical steels are iron-silicon alloys that provide
Low core loss and high permeability needed for more efficient and economical electrical
Transformers. Cold rolled grain oriented (crgo) grades of electrical steel are typically used
For transformer cores and large generators.
2.0application
2.1 the cgro is used regularly for cores in transformers.
3.0standard
3.1 this specification is prepared by taking guidance from bs 601:1973
4.0material
4.1 cold rolled grain oriented (crgo) grade m5, moh, zdkh as per bs 601:1973 and
Equivalent to jis c 2553
5.0properties
5.1 specifications and typical electrical and magnetic properties (see appendix 1)
6.0dimension and tolerance
6.1 dimension : as per the purchase order with the tolerance as given table below
Tolerance on width
Nominal width (mm)
Overup to and includingtolerance (mm)
0150+ 0 0.3
150500+ 0 0.5
001000+ 0 1.5
Tolerance on length
Nominal width (mm)
Overup to and includingtolerance (mm)
02000- 0 + 1.5
2000>2000- 0 + 2.0
Tolerance on length
The tolerance on the mean thickness, measured by contact micrometer, for any coil shall be
0.03 mm from the nominal thickness.
Tolerance on edge burr
The tolerance on edge burr not to exceed 0.05mm.
Tolerance on edge camber
Edge camber is the lateral departure of the edge of the strip from a straight line forming a chord, refer figure a:
Tolerance on edge camber of strip in coil shall not exceed 2 m in 2000 mm and shall be measured against a straight edge using a 2000 mm length cut from a coil.
7.0references
(1) bs 601: 1973, steel sheet and strip magnetic circuits of electrical apparatus.