Technical conditions for offshore plates of S355G7+N
1. Scope
The technical conditions apply to plates of S355G7+N with thickness not more than 150mm. (8mm-150mm)
2. Adopt standard:
EN10225 Weld-able structural steels for fixed offshore structures — Technical delivery conditions
3. Dimension, Shape, Weight and Permissible Deviation
The dimension, shape, weight and permissible deviation shall meet the requirements of EN10029.
Thickness tolerance: -0.30mm
Flatness: 4mm/m
Surface shot blasting or peeled.
4. Technical conditions
4.1 Chemical composition (Ladle analysis)
The chemical composition of plates shall be accordance with the following table 1.
Table 1 Chemical composition (Ladle analysis)
C | Si | Mn | P | S | Cr | Ni | Mo | V | Al | Nb | Ti | Cu |
Max 0.14 | 0.15- 0.55 | Max 1.65 | Max 0.020 | Max 0.007 | Max 0.25 | Max 0.70 | Max 0.08 | Max 0.060 | 0.015- 0.055 | Max 0.040 | Max 0.025 | Max 0.30 |
Note:
a. Cr+Mo+Ni+Cu <0.90%
b. Nb+V<0.06%
c. Nb+V+Ti<0.08%
4.2 Steel making process: EAF+LF/VD
4.3 Mechanical properties
The mechanical properties of S355G7+N shall meet the requirement as table 2.
Table 2 Mechanical properties
Thickness mm | Mechanical properties | ||
Yield strength MPa | Tensile strength MPa | Elongation % | |
8-40 | Min 355 | 460-620 | Min 22 |
41-100 | Min 335 | 460-620 | Min 22 |
101-150 | Min 320 | 460-620 | Min 22 |
4.4 Impact properties
Impact test in the longitudinal and transverse for plates of S355G7+N shall meet the requirements per table 3.
Table 3 Impact properties
Charpy-V Impact Test temp. Celsius degree | Longitudinal 1/4 Thickness | Longitudinal 1/2 Thickness | ||
Average impact energy | Average impact energy | |||
-40C | Min 50J | -40C | Min 50J | |
4.5 Grain size
Grain size for plates shall be according to S355G7+N.
4.6 Surface quality
The surface quality of plates shall be accordance with EN10163-2:2004.
4.7 Ultrasonic inspection
Plates shall be ultrasonic inspected per EN10160 S2E2.
4.8 Test method and inspection rules
Test items, sampling quantity, sampling method and test method shall conform to table 4.
Table 4 Test items for plates
No. | Test item | Quantity, Piece | Direction | Test menthod |
1 | Hardness | 1 | / | According to EN10225 |
2 | Tensile test | 1 (per heat treatment pc) | Transverse | |
3 | Charpy-V impact test at -40C | 6 (per heat treatment pc) | T/4 Longitudinal | |
4 | 6 (per heat treatment pc) | T/2 Longitudinal |
5. Package, marking and certificate
Package, marking and certificate shall conform to EN10225.
6. The third party inspection
The chemical composition, tensile test and Charpy -V impact test for plates of S355G7+N shall be witnessed by surveyor of ABS or DNV.
7. Delivery conditions
The delivery conditions for plates of S355G7+N shall be Normalized.
8. Other requirements
The other requirements for plates of S355G7+N shall be accordance with EN10225-2001.
MTC accordance with EN10204: 2004 3.2
