Technical conditions for plates of EQ70
1. Scope
The technical conditions apply to plates of EQ70 with thickness not more than 254mm. (10mm-254mm)
2. Adopt standard:
ABS rules.
ASTM A20/A20M Standard Specification for General Requirements for Steel Plates for Pressure Vessels
ASTM A370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products
3. Dimension, Shape, Weight and Permissible Deviation
The dimension, shape, weight and permissible deviation shall meet the requirements of ASTM A20/A20M.
Thickness tolerance: +/-1.52mm
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 |
Max 0.18 | 0.15- 0.35 | 0.95- 1.30 | Max 0.035 | Max 0.010 | 1.00- 1.50 | 1.20- 1.50 | 0.40- 0.60 | 0.030- 0.080 |
4.2 Steel making process: EAF+LF/VD (ESR)
4.3 Mechanical properties
The mechanical properties of EQ70 shall meet the requirement as table 2.
Table 2 Mechanical properties
Thickness mm | Mechanical properties | Lateral expansion
mm | Hardness test 1/4 T HB | |||
Yield strength MPa | Tensile strength MPa | Section shrinkage ratio % | Elongation % | |||
100 | Min 690 | 790-930 | Min 45 | Min 14 | Min 0.38 | Min 260 |
4.4 Impact properties
Impact test in the longitudinal and transverse for plates of EQ70 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 69J | -40C | Min 69J | |
4.5 Grain size
Grain size for plates shall be according to EQ70.
4.6 Surface quality
The surface quality of plates shall be accordance with ASTM A20/A20M.
4.7 Ultrasonic inspection
Plates shall be ultrasonic inspected per ASTM A578/A578M level C.
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 ASTM A370 |
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 A20.
6. The third party inspection
The chemical composition, tensile test and Charpy -V impact test for plates of EQ70 shall be witnessed by surveyor of ABS.
7. Delivery conditions
The delivery conditions for plates of EQ70 shall be Quenching +Tempering.
8. Other requirements
The other requirements for plates of EQ70 shall be accordance with EQ70.
MTC accordance with EN10204: 2004 3.2
