16 811 16 Materials and Semi-Finished Products for Switchgear Installations 16.1 Iron and steel 16.1.1 Structural steel, general The material specifications for structural steels to EN 10 029 apply to carbon steels and low-alloy steels: these are used in the hot-worked condition, and to a lesser extent after normalizing, for reasons of tensile strength and yield strength. The specifications are also valid for forgings, section steel, strip, and heavy and medium plates made from these steels. Weldability is better with low-carbon steels having less than 0.22% C. Weldability is best with steels of grade 3, e.g. S235 (St 37-3 JR), and poorest with steels of grade 1. Killed steels are to be preferred to rimmed steel, especially if segregation zones might be encountered when welding. Identification codes for structural steels are contained in EN 10027. This also shows the chemical composition and method of melting or casting. ABB_11_E_16 13.08.2007 9:43 Uhr Seite 811
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16
811
16 Materials and Semi-Finished Products forSwitchgear Installations
16.1 Iron and steel
16.1.1 Structural steel, general
The material specifications for structural steels to EN 10 029 apply to carbon steelsand low-alloy steels: these are used in the hot-worked condition, and to a lesser extentafter normalizing, for reasons of tensile strength and yield strength. The specificationsare also valid for forgings, section steel, strip, and heavy and medium plates madefrom these steels.
Weldability is better with low-carbon steels having less than 0.22% C. Weldability isbest with steels of grade 3, e.g. S235 (St 37-3 JR), and poorest with steels of grade 1.Killed steels are to be preferred to rimmed steel, especially if segregation zones mightbe encountered when welding.
Identification codes for structural steels are contained in EN 10027. This also showsthe chemical composition and method of melting or casting.
Outer Ø mm 16.0 20.0 25.0 32.0 40.0 50.0 63.0Inner Ø mm 13.3 17.3 22.1 29.0 37.0 47.0 59.9Min insertion mm 16 20 25 30 32 42 50
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 819
820
16.1.3 Stresses in steel components
The permissible stresses in steel components for transmission towers and structuresfor outdoor switchgear installations are laid down in DIN VDE 0210. Values for differentkinds of stress, such as tensile, shear, compressive and bearing stresses are specifiedfor the steel sections are given.
Remarks:
Structural steels to EN 10 025, screws and bolts to DIN 267. Permissible weld stressesfor welded towers are given in DIN 18800, Part 1.
According to VDE 0210, structural steels of grade S 235 JR (St 37-2) and above maybe used for overhead power lines.
16.2 Non-ferrous metals
16.2.1 Copper for electrical engineering
Various unalloyed grades of copper are used as conductor materials: oxidized,oxygen-free and oxygen-free deoxidized copper materials.
The most frequently used oxidized copper grades Cu-ETP and Cu-FRHC contain upto 0.04% oxygen, and in the soft condition have a conductivity of at least 58 MS/m, atensile strength of 200 MPa and are suitable for cold forming. Hydrogen embrittlementcan occur during heat treatment, soldering and welding unless an inert gasatmosphere (MIG, TIG) is used.
Oxygen-free copper Cu-OF (obtained from copper cathodes of maximum purity) istotally free of oxygen, also has a conductivity of at least 58 MS/m, is free of vaporizableelements and thus suitable for use in vacuum interrupters and in superconductortechnology. Oxygen-free deoxidized (with phosphorus) copper is only suitable for thatapplication in special grades (free of vaporizable elements).
Standards for semi-finished products in copper and copper alloys (with small amountsof additives) for use in electrical engineering
EN 13599:2002-07 to EN 13605:2002-10 for sheet, tubes, bars, sections and wires
Product designations
Description Relevant Material designation Condition Nominal dimensionsEN standard Material no. designation in mm
Sheet EN 13601 Cu-ETP R290 6.0 x 600 x 2000Sheet EN 13601 CW004A R290 6.0 x 600 x 2000
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 820
16
821
16.2.2 Brass and bronze
As brass and bronze are predominantly structural materials in electrical engineering,the stipulations for copper and copper alloys apply here for general use.
Material designations
Example 1 Designation to ISO 1190-1:1982-11: CuZn28 orMaterial no. to EN 1412:1995-12: CW504LBrass with 28% Zn for spring parts in plug connectors.
Example 2 Designation to ISO 1190-1:1982-11: CuSn6 orMaterial no. to EN 1412:1995-12: CW452KTin bronze with 6% Sn for sheets, bars, sections and wires.
See section 13.1.1 for special properties of conductor materials.
16.2.3 Aluminium for electrical engineering
Aluminium is used in electrical engineering both as a structural material, e.g. forenclosures, guides and force transmission components, and as a conductor material– and in that application both as a wrought alloy (wires and semi-finished products)and as a cast alloy (die cast cage rotors). Pure aluminium alloys (99.5% Al), alloys ofthe AlMgSi group and aluminium-zirconium alloys (TAL) are mainly used asconductors. Ultra-pure aluminium (99.99% and above) is used for special purposes(capacitor foil, semiconductor and low temperature technology).
The electrical conductivity and mechanical strength of aluminium alloys aredetermined by the alloy components, by mechanical forming and by heat treatment.As a rule, these two properties are found to change inversely to each other.
Material designations
Example 1 Designation to ISO 1190-1:1982-11: Cu-ETP orMaterial no. to EN 1412:1995-12: CW004A (formerly E-Cu58, E-Cu57; old designation: E-Cu)Preferred conductor material in switchgear, contains oxygen.
Example 2 Designation to ISO 1190-1:1982-11: Cu-OF orMaterial no. to EN 1412:1995-12: CW008A(formally OF-Cu; old designation: OFHC)For vacuum interrupter manufacture, oxygen-free.
Condition designations (Examples from EN 1173:1995-12)
M - As manufactured, without specified requirements for mechanical propertiesD - Drawn, without specified requirements for mechanical propertiesH... - Condition described with minimum value for hardness (Vickers or Brinell)R... - Condition described with minimum value for tensile strength in MPa (N/mm2)
See section 13.1.1 for special properties of conductor materials.
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 821
822
Standards for semi-finished products in aluminium and aluminium alloys for use inelectrical engineering
EN 14121:2003-08 for strips, sheets and platesEN 40501-2:1985-06 for tubesEN 40501-3:1985-06 for bars and sectionsEN 1715-1/-2:1997-11 for cast wire rods in EAl
Product designations
Description Relevant Material designation Condition Nominal dimensionsEN standard Material no. designation in mm
Sheet EN 14121 EN AW-1350A - F 6.0 x 600 x 2000
Sheet EN 14121 EN AW-EAl 99.5(A) - F 6.0 x 600 x 2000
Material designations
Example 1 Numerical designation to EN 573 (1:1994-12): EN AW-1350A orAlphanumerical designation to EN 573-2 (1994-12),Standard: EN AW–1350A [EAl 99.5(A)]Exception: EN AW-EAl 99.5(A) (formerly E-Al), mainly used as electrical conductors.
Example 2 Numerical designation to EN 573-1 (1994-12): EN AW-6101B orAlphanumerical designation to EN 573-2 (1994-12),Standard: EN AW-6101B [EAl MgSi(B)]Exception: EN AW-EAl MgSi(B)(formerly E-AlMgSi0,5), material for conductor bars of high tensile strength.
The prefix „E” before „Al” fundamentally identifies aluminium grades for electricalengineering. In the alphanumerical designation, the main alloy components follow the„Al”. Appended figures indicate the purity of the aluminium and the percentage of thecomponents.
Condition designation (to EN 515:1993-12)
F - As manufactured, without specified requirements for mechanical propertiesO... - annealed ) Each of the following figures is a code H... - strain hardened ) for details of the treatment and condition.T... - heat treated ) They are not indicators of mechanical
properties. See the relevant standards forsemi-finished products for those data.
See section 13.1.1 for special properties of conductor materials.
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 822
16
823
16.3
Insu
lati
ng m
ater
ials
16.3
.1S
olid
insu
lati
ng m
ater
ials
Tab
le 1
6-10
Ab
bre
viat
ions
and
pro
per
ties
of s
olid
insu
latin
g m
ater
ials
Abbr
evia
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ater
ial
Bulk
Bend
ing
Tens
ileIm
pact
Elas
ticity
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miti
ngTr
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ngEl
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cVo
lum
eDi
elec
tric
Prod
uct l
abel
tion
dens
ityst
reng
thst
reng
thst
reng
thm
odul
usth
erm
alco
nduc
tivity
tem
pera
-re
sista
nces
treng
htre
sistiv
ityco
nsta
ntex
pans
ion
ture
ISO
118
3IS
O 1
78IS
O 5
27IS
O 1
80IS
O 1
87IS
ODI
NIS
O 3
06IE
CIE
CIE
CIE
C11
359
5261
260
112
6024
3-2
6009
360
250
ρσ
bσ
za n
Eα
1λ
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mpara
tive
E dρ
Dε r
(50
Hz)
kg/d
m3
MPa
MPa
kJ/m
2M
Pa10
–4/K
W/(m
· K)
figure
kV/m
mΩ
· cm
Insu
latin
g m
ater
ials
for c
able
s an
d co
nduc
tors
PVC
-Ppo
lyvi
nyl c
hlor
ide
1.3
1 15
01
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160
600
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25
1015
3.5
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stra
lon,
Mip
olam
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with
out
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560
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able
insu
latio
n (X
LPE)
(VP
E)po
lyet
hyle
neru
ptur
e
(con
tinue
d)
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 823
824
Tab
le 1
6-10
(co
ntin
ued
)A
bb
revi
atio
ns a
nd p
rop
ertie
s of
sol
id in
sula
ting
mat
eria
ls
Abbr
evia
-M
ater
ial
Bulk
Bend
ing
Tens
ileIm
pact
Elas
ticity
Line
arTh
erm
alLi
miti
ngTr
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ngEl
ectri
cVo
lum
eDi
elec
tric
Prod
uct l
abel
tion
dens
ityst
reng
thst
reng
thst
reng
thm
odul
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erm
alco
nduc
tivity
tem
pera
-re
sista
nces
treng
htre
sistiv
ityco
nsta
ntex
pans
ion
ture
ISO
118
3IS
O 1
78IS
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27IS
O 1
80IS
O 1
87IS
ODI
NIS
O 3
06IE
CIE
CIE
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C11
359
5261
260
112
6024
3-2
6009
360
250
ρσ
bσ
za n
Eα
1λ
°CCo
mpara
tive
E dρ
Dε r
(50
Hz)
kg/d
m3
MPa
MPa
kJ/m
2M
Pa10
–4/K
W/(m
· K)
figure
kV/m
mΩ
· cm
Insu
latin
g m
ater
ials
for
foils
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mi-
finis
hed
prod
ucts
, st
ruct
. com
p.(th
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opla
stic
s,
mou
ldin
gs)
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poly
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ns16
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ica,
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amin
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heet
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olic
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st, P
heno
plas
tre
sins
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ould
ing
com
poun
d
(con
tinue
d)
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 824
16
825
(con
tinue
d)
Tab
le 1
6-10
(co
ntin
ued
)
Ab
bre
viat
ions
and
pro
per
ties
of s
olid
insu
latin
g m
ater
ials
Abbr
evia
-M
ater
ial
Bulk
Bend
ing
Tens
ileIm
pact
Elas
ticity
Line
arTh
erm
alLi
miti
ngTr
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ngEl
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cVo
lum
eDi
elec
tric
Prod
uct l
abel
tion
dens
ityst
reng
thst
reng
thst
reng
thm
odul
usth
erm
alco
nduc
tivity
tem
pera
-re
sista
nces
treng
htre
sistiv
ityco
nsta
ntex
pans
ion
ture
ISO
118
3IS
O 1
78IS
O 5
27IS
O 1
80IS
O 1
87IS
ODI
NIS
O 3
06IE
CIE
CIE
CIE
C11
359
5261
260
112
6024
3-2
6009
360
250
ρσ
bσ
za n
Eα
1λ
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mpara
tive
E dρ
Dε r
(50
Hz)
kg/d
m3
MPa
MPa
kJ/m
2M
Pa10
–4/K
W/(m
· K)
figure
kV/m
mΩ
· cm
Insu
latin
g m
ater
ials
for
stru
ctur
al c
ompo
nent
s(th
erm
opla
stic
s)
PA
66
poly
amid
e A
1.13
50-
70w
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t12
000
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1.0
0.2
120
600
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id A
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ptur
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A, Z
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with
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alog
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dur,
Poc
an,
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lybu
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000
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esta
dur,
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late
with
fibr
egla
ssC
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in
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Rpo
lyur
etha
ne (l
inea
r)1.
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t12
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0.2
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220
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ptur
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Sac
rylic
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ne s
tyre
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ur, T
erlu
ran
(con
tinue
d)
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 825
826
Tab
le 1
6-10
(co
ntin
ued
)
Ab
bre
viat
ions
and
pro
per
ties
of s
olid
insu
latin
g m
ater
ials
Abbr
evia
-M
ater
ial
Bulk
Bend
ing
Tens
ileIm
pact
Elas
ticity
Line
arTh
erm
alLi
miti
ngTr
acki
ngEl
ectri
cVo
lum
eDi
elec
tric
Prod
uct l
abel
tion
dens
ityst
reng
thst
reng
thst
reng
thm
odul
usth
erm
alco
nduc
tivity
tem
pera
-re
sista
nces
treng
htre
sistiv
ityco
nsta
ntex
pans
ion
ture
ISO
118
3IS
O 1
78IS
O 5
27IS
O 1
80IS
O 1
87IS
ODI
NIS
O 3
06IE
CIE
CIE
CIE
C11
359
5261
260
112
6024
3-2
6009
360
250
ρσ
bσ
za n
Eα
1λ
°CCo
mpara
tive
E dρ
Dε r
(50
Hz)
kg/d
m3
MPa
MPa
kJ/m
2M
Pa10
–4/K
W/(m
· K)
figure
kV/m
mΩ
· cm
Cas
t re
sin
mou
ldin
gs(d
urop
last
ics)
EP
epox
y re
sins
1.6
–1.8
70–8
017
510
–68
14 0
000.
30.
612
560
030
1015
4.2
Ara
ldite
60
% p
owde
r-(w
ith 6
0–70
% fi
ller)
ed q
uart
z, R
esod
ip
EP
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237
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220
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315
518
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+ w
oven
gla
ss s
ilk(fl
ame
resi
stan
t)to
VD
E 0
334
UP
unsa
tura
ted
poly
este
r1.
6–1
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00.
311
0-60
025
1015
4.5
–7.5
Sup
rapl
ast
resi
ns (w
ith 6
0-70
%13
0fil
ler)
UP
-Hgw
247
21.
6–1.
820
010
010
010
000
0.15
–0.3
0.3
130
500-
25–3
010
125.
0G
lass
mat
to
VD
E 0
334
(in s
heet
)60
0
PU
Rpo
lyur
etha
ne r
esin
1.6-
1.8
120
70-1
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10 0
000.
40.
811
060
030
1015
4,3
Bay
gal,
Bay
mid
urw
ith 6
0-70
% fi
ller
(con
tinue
d)
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 826
16
827
Tab
le 1
6-10
(co
ntin
ued
)
Ab
bre
viat
ions
and
pro
per
ties
of s
olid
insu
latin
g m
ater
ials
Abbr
evia
-M
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εr(50 Hz)
εrtanδ· 103
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 827
828
16.3.2 Liquid insulating materials
Mineral oils are predominantly used as liquid insulating materials in transformers, highvoltage cables (>110 kV), capacitors, instrument transformers, oil-cooled rectifiers andswitching devices. All these applications make use of the high dielectric strength(breakdown voltage) of mineral oil, which however can be greatly impaired by moistureor foreign bodies. When used in switching devices, oil also serves to influence thearcing process. In transformers, the dissipated heat in the windings is conducted awayby the oil, predominantly by convection. This depends upon the kinematic viscositybeing as low as possible in the entire service temperature range.
A further factor of decisive importance for the suitability of an oil is its resistance tooxidative ageing, which can lead to the formation of oil sludge, to increased viscosity,to tarnishing film on contact surfaces and to drops in dielectric properties. Resistanceto ageing can be improved by adding inhibitors.
In applications with especially high dielectric field stresses, such as capacitors,cables, instrument transformers and extra-high voltage transformers, so-called „gas-proof” insulating oils are notable for their ability to bind the hydrogen which may becreated by discharges in areas of very high dielectric field strength.
These versatile properties can be achieved in oil manufacture by selecting suitablecrude oil, distilling, refining and mixing with additives. As the requirements are varied,there is a wide range of oils available.
Synthetic esters or silicone oil are used in place of insulating oils in transformers whichare intended for particular applications (e.g. excavators or locomotives) or forparticular locations (e.g. hospitals) with a view to the potential environmental effectson the one hand and the fire risk on the other hand if a fault should occur.
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 828
16
829
Physical characteristics of insulating oil in standard quality, for information
Property Unit Transformer- Low temperature Liquid Transformeroil switchgear oil silicone ester
IEC 60296 IEC 60836 IEC 61099
Density kg/dm3 at max 0.895 max. 0.970 max. 1.00020 °C
Kin. viscosity mm2/s at max. 12 max. 3.5 40 ± 4 max. 3540 °Cmm2/s max. 1800 max. 400 – max. 3000at – 30 °C – 40 °C _ – 20 °C
Pour point °C max. – 40 max. – 60 max. –50 max. – 45
Thermal W/cmK ~ 0.0013 ~ 0.0015 ~ 0.0015conductivity at 25 °C
Spez. heat J/g K ~ 1.9 ~ 1.5 ~ 2.1coefficient of 1/K ~ 0.0008 ~ 0.001 ~ 0.001expansion
Dielectric ~ 2.2 ~ 2.4 ~ 2.55 ~ 3.2constant at 25 °C 25 °C 90 °C 25 °C
Dielectric lossfactor at 90 °C max. 0.500 max. 0.001 max. 0.03
Discruptive kV min. 30/70 min. 40 min. 45dischargevoltage
Flashpoint P.M. °C min. 135 min. 100 min. 240 min. 250
Ecological – Non biodegradable Non Nonaspects biodegradable biodegradable
ABB_11_E_16 13.08.2007 9:43 Uhr Seite 829
830
16.3.3 Gaseous insulating materials
Table 16-12
Properties of air and sulphur hexafluoride (SF6)
Gas Density1) Discruptive Dielectric constantdischarge voltage
kg/m3 Ed kV/mm (50 Hz) εr (50 Hz)
Air (dry) 1.205 2.1 1.000576Sulphur hexafluoride 6.07 6 1.002
1) at 20 °C and 1013 mbar
Curves of pressure, temperature and density for SF6 gas are shown in Fig. 11-1. The insulating and arc-quenching properties of this gas are dealt with in Sections10.4.4 and 11.2.2.
16.4 Semi-finished products
16.4.1 Dimensions and weights of metal sheets
Table 16-13
Weight per 1 m2 of sheet, in kg
Thickness Steel Aluminium Copper Brass Zinc Ribbed Profileds in mm sheettreadplate
Bolts and screws with metric thread, DIN 7990, dimensions in mmNuts EN 24034Washer DIN 7989
Bolt Thickness Thickness Width angles washer Drill holethreads of head of nut acrossNominal flats pass fordia- throught threadmeter dia. dia.d k m s e d1 s1