Chemical element composition of Chinese grade general strength and high strength marine steel plate AH32
AH32 Approaching Grade Lookup Table
Table 1 Chemical composition
| Grade | Chemical composition (mass fraction)/% | |||||||||||||||||||||||||||||||||
| C | Si | Mn | P | S | Cu | Cr | Ni | Nb | V | Ti | ||||||||||||||||||||||||
| AH32 | ≤0.18 | ≤0.50 | 0.90~1.60 | ≤0.030 | ≤0.030 | ≤0.35 | ＜0.20 | ≤0.40 | 0.02~0.05 | 0.05~0.10 | ≤0.02 | |||||||||||||||||||||||
| “Grain-refining elements Al, Nb, and V can be added to steel individually or in any combination. When added individually, their content should comply with the provisions of this table; if two or more grain-refining elements are added in combination, the provisions of the lower limit of the content of grain-refining elements in the table do not apply, and Nb+V+Ti ≤ 0.12% is required. The carbon equivalent Ceq of grades A, B, D, and E steel is less than 0.40%. The formula for calculating carbon equivalent is: Ceq = C + Mn/6. Any other added elements should be noted in the quality certificate. The maximum carbon content of Grade A steel shall not exceed 0.23%. When performing impact tests on Grade B steel, the lower limit for Mn content can be as low as 0.60%. For D and E grade steels with a thickness greater than 25 mm, the aluminum content should comply with the specifications in the table. Other grain-refining elements may be used upon consultation between the supplier and the buyer. When the thickness of AH32 to EH40 grade steel is no more than 12.5 mm, the minimum Mn content can be 0.70%. When F-grade steel contains aluminum, the nitrogen content shall not exceed 0.012%. The total aluminum (Alt) content can be measured instead of the acid-soluble aluminum (Als) content. In this case, the Alt content should not be less than 0.020%. |
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Table 2 Mechanical properties
| Grade | Tensile test a,b | Charpy (V-notch) impact test | ||||||||||||||||||||||||||||||||||
| Upper yield strength (ReH)/MPa |
Tensile strength (Rm)/MPa |
Elongation after fracture (A)/% |
Test temperature/℃ | Steel plate thickness(mm)Impact absorption energy(KV₂)/J | ||||||||||||||||||||||||||||||||
| ≤50 | >50～70 | >70～150 | ||||||||||||||||||||||||||||||||||
| Vertical | Horizontal | Vertical | Horizontal | Vertical | Horizontal | |||||||||||||||||||||||||||||||
| ≥ | ||||||||||||||||||||||||||||||||||||
| AH32 | ≥315 | 450～570 | ≥22 | 0 | 31 | 22 | 38 | 26 | 46 | 31 | ||||||||||||||||||||||||||