Where approved hull drawings call for ordinary-strength plate with A-level toughness, DNV Grade A — written NV/A or NV A in commercial practice — is the corresponding Det Norske Veritas normal-strength grade, not a generic structural-steel substitute. Gangsteel welcomes enquiries for NV A plate for shipbuilding and export projects; dimensions, delivery condition and documentation are agreed for the individual order.
The numerical requirements on this page for DNV Grade A (NV A) are transcribed from the official predecessor Det Norske Veritas Rules for Classification of Ships, Part 2 Chapter 2 Metallic materials, January 2016 edition, entering into force on 1 July 2016, Sec.1 B, including Tables B1, B2, B3 and B4, together with the general requirements of Sec.1 A. That January 2016 chapter is a predecessor document family; it is not the current DNV-RU-SHIP Part 2 Chapter 2. The current listed official ship-rules edition is DNV-RU-SHIP, July 2026, which enters into force on 1 January 2027. The later edition’s numerical tables have not been independently verified here. The edition named in the contract, the applicable certificate and the attending surveyor’s requirements govern any actual supply. The figures below are January 2016 rule requirements for plate, not a statement that material offered today complies with the July 2026 rules, and not measured results for a particular heat.
Grade Designation
DNV Grade A, also written NV A or NV/A, is a Det Norske Veritas normal-strength hull structural steel under Sec.1 B. The four ordinary-strength grades NV A, NV B, NV D and NV E share a specified minimum yield stress of 235 MPa and are subdivided by specified impact toughness; the letter is not a different tensile-strength range. Finished products are marked with the Society’s brand and the steel grade, for example NV A (Sec.1 A1101). The commercial writings DNV Grade A and NV/A refer to this same official grade; they are not different standards. This page addresses plate. Section and bar requirements are not presented as plate data.
Under Sec.1 A102, the plate and wide-flat requirements summarized here apply to thicknesses not exceeding 150 mm. For greater thicknesses, variations in the requirements may be permitted for particular applications. Through-thickness (‘Z’) quality, where needed, is a supplementary Sec.1 E requirement (quality classes Z25 and Z35) and is not implied by the base grade name or by this product title.
Key Advantages of A Steel Plate
- Defined ordinary-strength level: a specified minimum yield stress of 235 MPa and a tensile-strength range of 400–520 MPa under Table B3, giving a clear basis for selection against approved hull drawings.
- A-level toughness is specified at +20°C. For plate not more than 50 mm thick, Table B3 does not require impact testing; thicker plate has conditional requirements, which are laboratory conditions and not a minimum service temperature.
- Chemistry and deoxidation are controlled by Table B1 on a heat-analysis basis, including the C + 1/6 Mn limit of 0.40%.
- Grade, thickness, delivery condition and documentation can be reviewed together for the actual order; this overview does not imply a certified stock lot.
Chemical Composition (Heat Analysis)
Table values are taken from a heat analysis (Sec.1 A401): the composition of each heat is determined on a sample taken preferably during pouring of the heat. When several heats are tapped into a common ladle, the ladle analysis applies and shall remain within the same specified limits. Values are percentage by mass, maximum unless shown as a range or as a minimum. They are rule limits, not typical mill results and not product-analysis tolerances.
Table B1 gives chemical composition limits and deoxidation practice for NV A. When fine-grain practice is applied, B201 refers to the Table C1 limits for Al, Nb, V and Ti.
| Element | Heat-analysis requirement |
|---|---|
| Carbon, C | 0.21 max for plate (0.23 max applies to sections, which are not presented as plate data here) |
| Silicon, Si | 0.50 max |
| Manganese, Mn | Minimum 2.5 × C |
| Phosphorus, P | 0.035 max |
| Sulphur, S | 0.035 max |
| Aluminium, Al | No limit stated in Table B1 (“–”). If fine-grain practice is applied, the Table C1 limits for Al, Nb, V and Ti apply (B201). |
| C + 1/6 Mn | Shall not exceed 0.40% |
| Deoxidation | For t ≤ 50 mm: any method except rimmed steel. For t > 50 mm: killed. Rimmed steel may be accepted for sections up to 12.5 mm, which is a section provision, not a plate supply route on this page. |
Mechanical Properties
Table B3 mechanical properties apply to normal-strength steel. MPa is numerically equal to N/mm². Unless otherwise agreed, for plates and wide flats 600 mm wide or more, tensile test pieces are transverse and impact test pieces are longitudinal (Sec.1 A605).
| Property | NV A requirement (Table B3) |
|---|---|
| Yield stress ReH, minimum | 235 MPa |
| Tensile strength Rm | 400–520 MPa |
| Elongation A5, minimum | 22% |
For full-thickness flat tensile test pieces 25 mm wide with a 200 mm gauge length, Table B3 reduces the minimum elongation (%) to the following values. These figures must not be copied onto the A5 basis.
| Thickness, mm | t ≤ 5 | 5 < t ≤ 10 | 10 < t ≤ 15 | 15 < t ≤ 20 | 20 < t ≤ 25 | 25 < t ≤ 30 | 30 < t ≤ 40 | t > 40 |
|---|---|---|---|---|---|---|---|---|
| All ordinary-strength grades | 14 | 16 | 17 | 18 | 19 | 20 | 21 | 22 |
Table B4: impact testing is not required for NV A plates with t ≤ 50 mm; for 50 mm < t ≤ 150 mm the maximum impact test unit is 50 tonnes. Tensile test units are a maximum of 50 tonnes (B402).
These tables state January 2016 rule requirements for DNV Grade A, not evidence of certificates currently held by Gangsteel and not test results for a particular plate. Before purchase, confirm the contractual rules edition, the manufacturer’s approval for the grade, thickness and delivery condition, the inspection and certification scope, and the actual test results in the documentation for the offered material.
Charpy V-Notch Impact Requirements
Energies are minimum averages for a set of three standard Charpy V-notch test pieces (Sec.1 A703). Table values are average minima; a single-specimen minimum is not stated in these mechanical-property tables and is not invented here. The test temperature is a laboratory condition, not an approved minimum service temperature.
| Plate thickness t | Test temperature | Minimum average, longitudinal (J) | Minimum average, transverse (J) |
|---|---|---|---|
| t ≤ 50 mm | +20°C | Not required | Not required |
| 50 mm < t ≤ 70 mm | +20°C | 34 | 24 |
| 70 mm < t ≤ 150 mm | +20°C | 41 | 27 |
Table B3, note 3: impact tests for grade A over 50 mm thickness are not required when the material is produced using fine-grain practice and supplied in either the N or TM condition. Test direction follows A605.
Delivery Condition and Weldability
Abbreviations follow Sec.1 A500: AR as-rolled, NR normalising rolling, N normalising, TM thermo-mechanical rolling, and QT quenching and tempering. Where more than one condition is permitted, the manufacturer may supply only conditions for which it is approved. The following entries are the plate column of the official table; section-column permissions are not shown as plate data.
| Plate thickness | Permitted plate conditions (Table B2) |
|---|---|
| t ≤ 50 mm | AR, NR, N, TM |
| 50 mm < t ≤ 150 mm | AR when especially approved; NR, N, TM |
No carbon-equivalent maximum table is given for normal-strength steel in Sec.1 B. When a carbon equivalent is required, Sec.1 A405 calculates Ceq from the heat analysis using the stated formula; Pcm may be used subject to agreement. Those formulae are not converted here into invented numerical limits.
Available Dimensions
Under Sec.1 A102 of the January 2016 chapter, the plate and wide-flat requirements summarized here apply to thicknesses not exceeding 150 mm. Greater thicknesses may be considered only with the variations permitted for the particular application. Sec.1 A903 states that, for plates and wide flats, the minus tolerance on the ordered nominal thickness shall not exceed 0.3 mm; this is a rule tolerance, not a stock-size list. Width, length, edge condition, quantity and processing are agreed for the order. This page does not list inventory quantities or implied mill stock sizes.
Main Applications
Sec.1 A101 applies these rolled steels to the construction of hulls and other marine structures. DNV Grade A is typically considered for ordinary-strength hull envelope and primary members — shell plating, decks, bulkheads and similar structure — where the approved material schedule specifies this grade and toughness letter. Selection remains a design and classification decision. The Charpy test temperature, where applicable, is a laboratory condition and is not by itself an approved minimum service temperature.
Equivalent Grades of A
NV A and the commercial writings of DNV Grade A name the same Det Norske Veritas grade; they are not cross-society equivalents of one another. The table below lists similarly named official product pages on gangsteel.com for comparison only. Other-society figures are not used as DNV requirements. Automatic substitution is not permitted.
| Society / standard | Comparable grade | Qualification |
|---|---|---|
| ABS | ABS Grade A | Comparable designation at the same commercial strength and toughness letter. Chemistry, tensile range, impact energy, thickness scope, delivery condition, sampling and certification follow that society’s own rules and the contractual edition — not the January 2016 DNV tables on this page. Not a drop-in substitute; designer and classification approval are required before any replacement. |
| BV | BV Grade A | Comparable designation at the same commercial strength and toughness letter. Chemistry, tensile range, impact energy, thickness scope, delivery condition, sampling and certification follow that society’s own rules and the contractual edition — not the January 2016 DNV tables on this page. Not a drop-in substitute; designer and classification approval are required before any replacement. |
| LR | LR Grade A | Comparable designation at the same commercial strength and toughness letter. Chemistry, tensile range, impact energy, thickness scope, delivery condition, sampling and certification follow that society’s own rules and the contractual edition — not the January 2016 DNV tables on this page. Not a drop-in substitute; designer and classification approval are required before any replacement. |
| GL (Germanischer Lloyd) | GL Grade A | Comparable designation at the same commercial strength and toughness letter. Chemistry, tensile range, impact energy, thickness scope, delivery condition, sampling and certification follow that society’s own rules and the contractual edition — not the January 2016 DNV tables on this page. Not a drop-in substitute; designer and classification approval are required before any replacement. Historical Germanischer Lloyd designation; GL’s ship classification is now within the DNV organisation. Current certification follows the society and edition named on the contract. |
No official gangsteel.com product page was identified in the CCS, KR official categories for a corresponding grade, so no comparable URL is listed for those societies. No missing-grade address is invented.
Any proposed replacement requires a complete comparison of chemistry, strength, toughness, test temperature, thickness scope, delivery condition, sampling, mill approval and certification, and must be accepted by the designer and the relevant classification society under the contractual rules edition.
Related Products
- DNV Grade B steel plate
- DNV Grade D steel plate
- DNV Grade E steel plate
- DNV Grade AH32 steel plate
- DNV Grade AH36 steel plate
- DNV shipbuilding steel plates
Frequently Asked Questions (FAQ)
What is DNV Grade A (NV A) steel plate?
DNV Grade A, also written NV A or NV/A, is a Det Norske Veritas ordinary-strength hull structural plate grade with a specified minimum yield stress of 235 MPa. The letter A identifies its toughness level within that family. The numerical tables on this page are taken from the January 2016 predecessor chapter, not from a verified July 2026 transcription.
Does the impact test temperature define the service limit of DNV Grade A?
No. DNV Grade A is associated with a Charpy test temperature of +20°C under the January 2016 Table B3 requirements, including any thickness exemptions described above, but that laboratory temperature is not a blanket minimum operating temperature. The vessel or component requires its own approved material selection.
Is DNV Grade A always supplied in the same delivery condition?
No. Permitted plate conditions for DNV Grade A are those in Table B2 of the January 2016 chapter, subject to the manufacturer’s approval. The grade name alone does not fix the delivery condition.
Does DNV Grade A automatically include through-thickness Z quality?
No. DNV Grade A identifies the base grade. Through-thickness quality (Z25 or Z35) is a supplementary requirement under Sec.1 E and must be specified, produced and tested separately. These product titles do not state Z35, and this page does not imply stock Z-quality plate.
Can another shipbuilding grade replace DNV Grade A?
Not automatically. DNV Grade A must match the approved design and the contractual classification requirements. A different toughness letter, strength family, rules edition or society designation needs a technical and approval review before substitution. Similarly named grades of other societies are comparison candidates only.
What should an enquiry for DNV Grade A include?
Include DNV Grade A (and the official designation NV A), the rules edition that will govern the contract, dimensions, quantity, delivery condition, required inspection documentation, and any additional testing or through-thickness requirements. Availability, documentation and delivery are confirmed for the specific enquiry; none is implied by this overview.
Contact Gangsteel with your DNV Grade A plate specification and project requirements for an order-specific technical and commercial review.