Catalogue of Seven Diamonds (920 KB) 
Way of nomination cold rolled steel in DIN 1623 part1
- The sign which specifies the steel grade.
- The Sign which specifies surface appearance.
- The sign which specify the surface finish.
Specification |
Sign |
Name |
|
Defects in surface which doesn’t affect forming and coating. |
O3 |
Normal Surface |
surface appearance |
Free of defect |
O5 |
Best surface |
|
Shiny surface(Ra<0.4μm) |
b |
Specially smooth |
surface finish |
Surface is uniformly matt . (Ra<0.9μm) |
g |
Smooth |
|
(0.6<Ra<1.9μm)Surface is uniformly matt |
m |
Matt |
|
Surface is rough (Ra>1.6μm) |
r |
Rough |
Example: St12 O3 r is St12 steel and has a normal surface and rough surface.
Cold rolled steel standard: DIN 1623-part 1-1983
Hardness (max) |
Elongation (min) |
Yield Strength (N/mm2) |
Tensile Strength (N/mm2) |
Max%C |
Material Number |
Grade |
||
HRF |
T<= 6/0 |
6/0 <t< 1 / 1 |
||||||
HR 30T |
HRBm |
|||||||
94 |
60 |
65 |
28 |
280 |
410-270 |
12/0 |
0330/1 |
St12 |
90 |
55 |
57 |
32 |
250 |
370-270 |
10/0 |
0333/1 |
USt13 |
88 |
53 |
55 |
34 |
240 |
370-270 |
1/0 |
0347/1 |
RRSt13 |
86 |
50 |
50 |
38 |
210 |
350-270 |
08/0 |
0348/1 |
St14 |
- For t 7/0> (thickness) 20 N/mm2 is added to the yield strength.
- For t 7/0> (thickness) 2 is subtracted from elongation.
Specification |
Sign |
Name |
|
Shinny surface (Ra<= 4/0 μm) |
b |
Especially smooth |
Surface finish |
Surface is uniformly matt (Ra<= /0 9μm) . |
g |
Smooth |
|
Surface is uniformly matt ( 6/0 <Ra< /1 9μm) . |
m |
Matt |
|
Rough Surface (Ra> 6/1 μm) |
r |
Rough |