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7755 Ballantyne Commons Parkway, Suite 102, Charlotte, NC 28277, USA
Tel:(1 704) 845-2150 Fax:(1 704) 321-2443 E-MAIL: info@queencitysteel.net | |||||
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RUS-CORE*
(Grain Oriented Steel for Transformer
Cores)
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In December of 2005 the
Last year, NLMK
initiated a major Investment Program to modernize the equipment and processing
technologies on both production sites: in Ekaterinburg (VIZ-Stal) and Lypetsk
(NLMK). Upon completion
(2010-2011), this will reinforce NLMK’s position as a world leader in
producing high quality GO by adding High Permeability steel (HiB) to the wide
range of regular grades (RGO) produced today.
Presently, NLMK supplies regular (R) and selected (S) grades of GO in
0.23 –
NLMK has an established network of trade offices worldwide and all the
logistics to ensure timely supply of GO in coils (up to
1.
Delivery
Formats, Gauges, Dimensions
Delivery Formats |
Geometry
Parameters |
Gauges and Sizes,
mm |
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RUSCORE-R |
RUSCORE-S |
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Coils and Strips |
Thickness |
0,23; 0,27;0,30; 0,35; 0.50 |
0.27; 0.30 |
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Width |
Coil |
930;970;1000 *) |
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Strip |
50 - 500, (with |
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Coil and Strip ID |
508-512 |
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Sheets |
Width and thickness |
Same as for coils
and strips |
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Length |
1500 - 3000 |
*) Coils over
2. Technical
Characteristics fo RUS-CORE grades
2.1
Typical Magnetic Properties 1)
Grade 2) |
Nominal 3) Thickness, mm |
Specific Core Loss 4) W, В/кг |
Flux Density, B, Тeсла |
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1.5/50 |
1.7/50 |
В8 |
В25 |
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NV23S |
0,23 |
Properties
defined depending on intended use by the customer |
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NV27P-100 |
0,27 |
0.70 |
0.99 |
1,89 |
1,96 |
NV27S-105L |
0.72 |
1,04 |
1,87 |
1,95 |
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NV27S-110 |
0,75 |
1,08 |
1,87 |
1,94 |
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NV27S-120 |
0,80 |
1,18 |
1,86 |
1,94 |
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NV27S-130 |
0,84 |
1,27 |
1,85 |
1,94 |
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NV27S-140 |
0,89 |
1,36 |
1,85 |
1,93 |
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NV30P-105 |
0.30 |
0.73 |
1,04 |
1,88 |
1,95 |
NV30S-110L |
0.76 |
1,08 |
1,87 |
1,94 |
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NV30S-120 |
0,80 |
1,18 |
1,86 |
1,94 |
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NV30S-130 |
0,85 |
1,27 |
1,85 |
1,94 |
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NV30S-140 |
0,89 |
1,36 |
1,84 |
1,93 |
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NV35S-120 |
0.35 |
0,90 |
1,19 |
1,87 |
1,94 |
NV35S-130 |
0,94 |
1,27 |
1,86 |
1,94 |
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NV35S-145 |
0.99 |
1,40 |
1,85 |
1,93 |
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NV50S-150 |
0,50 |
1,42 |
2.00 |
1.84 |
1,91 |
NV50S-200 |
1.60 |
2.30 |
1.82 |
1,90 |
Notes: 1) Guaranteed values (maximum for
Core Loss and minimum for Flux Density) provided for individual coil, average guaranteed values provided for
one shipment and for the whole
contract, depending on the order size (statistical analysis is used).
2)
Grades with indices S and P certified
by Epstein method (IEC 60404- 2:1996), grades with index L – by Single
Sheet method (IEC 60404-3:1992).
Grades with index L shall not be used to produce laminations and
cores subject to stress rellief anneal
3)
For thickness, the typical (actual) values presented
in section 2.3 of this brochure.
4) Core Loss at 60 Hz = Core
Loss at 50 Hz x 1.31
2.2
Magnetic properties vs. Flux Density (B) and Field Strength (H)
Graphs for W=f(B)
and VA=f(B) for some of the grades listed in the above table presented
at the end of this brochure.
Polynomial equations for W=f(B) and
VA=f(B), as well
as graphs for
B=f(H), emu = f(B), and H/m = f(B) may be requested through our local sales
offices.
2.3 Thickness, Width, Mechanical, and
Physical Properties
Nominal thickness (mm) |
Thickness, microns |
Stacking Factor, % |
Hardness |
Number of bends |
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HV5 |
HR30 |
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Typical |
+/- |
Typical |
Mini- mum |
Aver- age |
Range |
Aver- age |
Range |
Typical 1) |
|
0.23 |
226 |
10 |
95.0 |
94.5 |
190 |
186-193 |
75 |
73-78 |
>10 |
0.27 |
262 |
10 |
95.8 |
95.0 |
186 |
182-190 |
74 |
71-77 |
>10 |
0.30 |
293 |
10 |
96.4 |
95.5 |
183 |
180-186 |
73 |
69-76 |
>10 |
0.35 |
341 |
15 |
97.0 |
96.0 |
177 |
173-182 |
71 |
68-73 |
>10 |
0.50 |
483 |
30 |
98.2 |
96.5 |
175 |
170-178 |
70 |
67-72 |
>10 |
1) Guaranteed value = 1
Nominal thickness (mm) |
Yield Strength, N/мм2 |
Tensile Strength, N/мм2 |
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Along RD |
Across RD |
Along RD |
Across RD |
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Aver-age. |
Range |
Aver-age. |
Range |
Aver-age. |
Range |
Aver-age. |
Range |
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0.23 |
330 |
315-345 |
350 |
337-362 |
359 |
354-365 |
402 |
393-407 |
0.27 |
326 |
312-340 |
345 |
330-360 |
354 |
350-360 |
395 |
388-400 |
0.30 |
320 |
310-330 |
340 |
325-355 |
350 |
345-355 |
390 |
385-396 |
0.35 |
314 |
305-325 |
333 |
320-345 |
345 |
335-353 |
384 |
379-388 |
0.50 |
305 |
290-320 |
325 |
315-335 |
340 |
330-350 |
380 |
373-384 |
Nominal thickness (mm) |
Camber, mm |
Burr, micron |
Waviness, maximum |
Width tolerance, mm |
Residual Stress (deviation from straight line after cut along RD) |
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% |
мм |
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0.23 |
</= 0.5 for
|
<
20 (except
coils with mill edge) |
1.0 |
2.0 |
<
+0.8 for width
> <
+0.5 for width
= 250 – <
+0.3 for width
< |
</= Measured
only for strips > |
0.27 |
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0.30 |
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0.35 |
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0.50 |
Nominal thickness (mm) |
Density кg/м3 |
Specific Resistivity mOhm/см3 |
Elongation, % |
Ageing corefficient, К 1) |
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Along RD |
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Average |
Range |
Average |
Range |
% |
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0.23 |
7650 |
48-49 |
20 |
16-24 |
45 |
40-49 |
<2 |
0.27 |
18 |
15-22 |
43 |
38-46 |
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0.30 |
16 |
13-20 |
40 |
36-42 |
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0.35 |
15 |
12-18 |
37 |
33-40 |
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0.50 |
12 |
9-16 |
32 |
28-35 |
<3 |
1) К=100*(W2-W1)/W1, where W1 = core loss before and
W2 = core loss after the Epstein sample is annealed for 24 hrs at 225 oC (according to EN
10107:2005)
.3. Insulation
Coatings
3.1 General information.
RUS-Core steel is supplied
with one of three types of coating:
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Conventional, designated CC (Coating Conventional)
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Stress Coating, designated CM (Coating to lower Magnetostriction)
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Soft Coating, designated CS (Coating Soft).
СС и СМ coatings applied on ECOMAG-Core grades intended for
stacked and wound cores produced by slitting and cutting the steel strip
(with disc or guillotine knives), while CS is typically1) applied on GO
While
technologically the СС и СМ coatings are
similar to С5 + С2 type (ASTM designation),
their chemistry differs in such a way that СМ has coefficient of thermal expansion ~ half that of CC. As a result, CM induces higher
tensile stress in the steel, which leads to lower core loss and reduces
sensitivity to stress, introduced during core manufacturing. In addition, CM reduces acoustic
noise in stacked cores (by 2-4 dB at operating flux density = ~ 1.7 Tesla).
Properties of CS coating are similar to that
of С4 – type coating (ASTM designation).
3.2 Typical Technical Characteristics of
Insulation Coatings
Type of coating |
(coil average) |
Thickness per surface |
Adherence after bend over % undamaged, per side |
Ability to withstand thermal treatment in protective
atmosphere |
|
Ohm*см2 |
micron |
Convex |
Concave |
Hrs at Т
, оС |
|
CC |
> 20 |
2-3 |
100 |
> 90 |
> 10
при 800-900 |
CM |
> 30 |
2-3 |
100 |
> 90 |
>10
при 800-900 |
CS |
> 5 |
1-2 |
100 |
100 |
</=0.5
при </= 750 |
1)
Calculated
according to IEC 60404-11:1991, after measuring
2) On customer’s request, adherence can be tested
for other bending radii (e.g., 10 or
4. Quality
Assurance (main elements)
NLMK incorporates complete cycle of steel-making operations: from charge preparation to testing and packaging finished GO coils, strips and sheets. All production processes for Rus-Core are subject to consistent and uniform quality control procedures, which certified according to ISO 9001-2000. Considering the critical importance of hot band processing to obtain consistency of magnetic properties of the final product, manufacturing process is organized in such a way that one hot-rolled band is processed as one piece (“master coil”) from pickling to flattening anneal.
4.1 Control of Magnetic Properties
Production
of RUS-Core steel of given nominal gauge follows very similar processing steps,
which requires thorough monitoring of magnetic quality to determine actual
grade to which the finished coil shall be certified. Four-step procedure is used to
achieve statistically sound grade designation for coils with the same nominal
gauge.
First,
magnetic permeability is continuously monitored along the whole length of a
master coil immediately after flattening anneal.
Second,
specific core loss (Single Sheet method) and
Third,
samples are cut from both ends of each finished coil (typically, two finished
coils are produced from the master one) and tested in SST, which provides
information for preliminary grade designation.
Finally,
the coil grade certified, using the core loss value for Epstein test from the
end, which corresponds to the worst SST result.
While
Epstein test is used to determine actual grade for all coils, except the ones
with domain refined (have index L in grade designation), data measured
with SST method can be included in quality certificate (if requested by
customer). The guaranteed values
(individual coils) and typical values (shipment and contract) shall be agreed
between customer and supplier.
All guaranteed, typical
and average magnetic characteristics as well as Standard Deviations (for
shipments no less than 10 coils) are derived from statistical analysis of
actual production for 3 to 6 months preceding certification process.
4.2
Other Quality Parameters.
All quality parameters monitored and
measured according to QA manuals, which comply with ISO 9001-2000, major
international standards and Russian national Standards (GOST). In some cases, quality control
procedures may be modified or added, if customer has specific requirements,
which the mill is capable to satisfy.
Several procedures for quality parameters our customers consider as most
relevant ((besides magnetic properties) are commented below in some detail.
Franklin
current, IF, which used to calculate
coating’s Resistance, RF, is measured for both ends of master
(immediately after flattening anneal) and finished (full width, before trimming
or slitting). Every time IF
is measured in eight test points (two per surface on each end) and the coil is
certified using average value of RF, derived from measured IF. If requested by customer, minimum RF
value or maximum IF value (out of eight test
points) can be used as certification parameter.
Coating
thickness is measured periodically to ensure 2 to 3 microns of ceramic
oxides on each surface for CC and CM coatings and 1 – 2
microns of semi-organic compound on each surface for CS coating.
Strip
thickness is continuously monitored during cold rolling and finishing
operations. The data for each finished
coil stored (in digital format) for 6 month after the coil is shipped and
it’s available to the customer on request. For certification, actual thickness is
calculated for two ends of each coil using equation: t = m/(w*l*r),
where m, w,
l
represent mass, width and length of single sheet sample (used to test specific
core loss) and r
= assumed steel density = 7.65 g/cm3. If necessary, quality certificate
may include value of maximum thickness deviation along the coil (from
continuous thickness monitoring of the finished coil)
Burr
height is guaranteed not to exceed 20 micrometers (mm) for strips slit at the mill to customer
specified width (<
4.3 Quality Certificate
Typical
format of Quality Certificate (QC), which is provided to the customer with each
shipment of RUS-Core steel presented below. On customer request, the QC may include
data for other technical characteristics, such as: specific core loss tested at
60 Hz, value of specific apparent loss (exciting power, VA/kg), values per
pound instead of kilogram, core loss and/or exciting power at
customer-specified flux density, actually measured Franklin current instead of
calculated Franklin resistance, maximum thickness deviation, etc.
NLMK/VIZ-Stal
EXPORT
QUALITY & QUANTITY
CERTIFICATE
Manufacture:
Package: Metallic case
Contract #:
Coating: CC
Purchase / Order #:
Lamination factor:
Description of goods: COLD ROLLED GRAIN ORIENTED
SILICON STEEL. PRIME, COILS
R wagon:
Standard
RB/L:
Grade |
Mill and
shipping coil numbers |
Width, mm |
Weight |
Magnetic values
for the worst end of a coil |
average per coil. |
Thickness, Actual value, microns |
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Core Loss, W/kg @ 50 Hz and B= |
Flux Density В8, |
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Gross |
Net |
1.5
Т |
1.7
Т |
Тесла |
Ohm.cm2/ lamination |
Front |
Back |
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1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
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NV27S-110 |
103554 |
07905-2 |
970 |
4520 |
4430 |
0.77 |
1.08 |
1.87 |
35 |
264 |
259 |
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NV30S-120
|
205543 |
07910-1 |
980 |
4160 |
4070 |
0.81 |
1.17 |
1.87 |
52 |
287 |
293 |
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Total:
Signature
Number of coils:
Stamp
Date:
Following pages contain graphs for typical dependence of Core
Loss (W/kg) and Exciting Power (VA/kg)
on Flux Density (Tesla) at 50 and 60 Hz.
Similar graphs for all
other grades, as well as graphs for DC Magnetization, Magnetic Permeability and
Exciting Force for ALL grades listed in Table 2.1 (see above) are available upon
request, which shall be addressed to our local sales office.