Grade B (ship)
Data under reviewGrade B is the ordinary-strength hull steel with a 0 °C impact guarantee — the default shell and deck plate for vessels in general service under classification-society rules (IACS UR W11 / ASTM A131 / GB/T 712). Its manganese window is set tighter than Grade A to support the toughness requirement.
Chemical composition
| Element | Content (%) |
|---|---|
| C | ≤0.21 |
| Si | ≤0.35 |
| Mn | 0.80–1.20 |
| P | ≤0.035 |
| S | ≤0.035 |
| Note | Chemistry per classification-society rules (IACS UR W11) |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Yield strength | ≥235 MPa |
| Tensile strength | 400–520 MPa |
| Impact | 0 °C, ≥27 J longitudinal (≤50 mm) |
| Density | 7.85 g/cm³ |
Heat treatment
Supplied as-rolled under class survey; impact tested at 0 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | A131 B |
| jis | KB (near) |
| gb | B (GB/T 712) |
Compare side by side: Grade B (ship) vs Grade A (ship) · Grade B (ship) vs Grade D (ship)
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Hull shells, decks and bulkheads of general-service vessels, barges, workboats.
Processing: Standard shipyard welding; certificates from the vessel’s classification society are part of delivery.
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Ask for a quotationVisit NasteelSource: Classification-society rules (IACS UR W11) published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.