GL GRADE D and GL-D steel plate supplier

Gangsteel supplies GL Grade D (GL-D) shipbuilding steel plate against the Germanischer Lloyd Section 1 B hull-structural grade identified below, the contract edition and the issued certificate.

Numerical requirements on this page are taken from a complete official-publication chapter transcription of Germanischer Lloyd, Rules for Classification and Construction, II Materials and Welding, 1 Metallic Materials, 2 Steel and Iron Materials, Edition 2009, in force 1 April 2009, Section 1 B “Normal and Higher Strength Hull Structural Steels,” Tables 1.2, 1.5 and 1.7, together with the general provisions of Section 1 A. An official binary PDF of that 2009 GL AG edition was not obtained for this page, and the figures were not visually confirmed against original page images. That 2009 GL chapter is a historic official predecessor. After the DNV–GL merger, the GL II-1-2 book was succeeded by DNV-RU-SHIP Part 2 Chapter 2. The current listed official ship-rules edition is DNV-RU-SHIP, July 2026, entering into force on 1 January 2027; those later tables have not been independently verified here. The figures below are 2009 GL rule requirements for plate, not a claim that material offered today complies with a later edition, and not measured results for a particular heat. The contract edition, the certificate and the attending surveyor govern any actual supply.

Grade Designation

The official designation in the 2009 GL rules is GL-D. Commercial forms include GL Grade D and GL D. It is one of the four normal-strength grades GL-A, GL-B, GL-D and GL-E.

Key Advantages of GL-D Steel Plate

GL Grade D (GL-D) is a weldable normal-strength hull structural steel in 2009 GL Section 1 B, Table 1.7, with the −20 °C impact class and the exemptions noted in the mechanical table. It is used for welded ship structural members where this GL grade is specified.

Chemical Composition (Ladle Analysis)

Table 1.2, ladle analysis (Section 1 A: melt analysis; B.2.3: smelt analysis, ladle analysis).

Element / requirement	Value	Notes
Deoxidation	For t ≤ 25 mm, killed; for t > 25 mm, fully killed and fine grain treated.	—
C, max. (%)	0.21	—
Mn, min. (%)	0.60	—
C + Mn/6, max. (%)	0.40	Applies to the ladle analysis.
Si, max. (%)	0.35	—
P, max. (%)	0.035	—
S, max. (%)	0.035	—
Al (acid soluble), min. (%)	0.015	Applies to Grade GL-D over 25 mm thick (Table 1.2, notes 5 and 6). Total aluminium may be used in place of the acid-soluble part and shall then be not less than 0.020 %. GL may also specify a maximum aluminium limit. Other grain-refining elements may be permitted subject to approval.
Cu, max. (%)	0.30	Melt maximum, Table 1.2, note 7.
Cr, max. (%)	0.20	Melt maximum, Table 1.2, note 7.
Ni, max. (%)	0.40	Melt maximum, Table 1.2, note 7.
Mo, max. (%)	0.08	Melt maximum, Table 1.2, note 7.

TM-rolled supply may be allowed or required to vary from this chemistry (Table 1.2, note 4). Slight variations may be agreed with GL for plates and wide flats over 50 mm (B.4.1). Further process additions are to be stated in the manufacturer’s certificate (note 8).

Mechanical Properties

Tensile specimens: transverse for plates and wide flats ≥ 600 mm wide, otherwise parallel to the rolling direction (A.8.2.2). Yield is ReH or Rp0.2 (B.6.1). Impact specimens are generally longitudinal (B.6.3). Impact temperatures are laboratory conditions, not approved minimum service temperatures. The table is a rule requirement, not a certificate already issued for a particular plate.

Property	Requirement	Notes
Yield strength ReH or Rp0.2, min.	235 N/mm²	Table 1.7.
Tensile strength Rm	400–520 N/mm²	Table 1.7.
Elongation A, Lo = 5.65 √So, min.	22 %	Table 1.7 also specifies elongation for Lo = 200 mm flat specimens by thickness.
Impact test temperature	−20 °C	Laboratory test condition only, not an approved minimum service temperature.
KV, t ≤ 50 mm, long. / transv., min. average	27 J / 20 J	Table 1.7.
KV, 50 mm < t ≤ 70 mm, long. / transv., min. average	34 J / 24 J	Table 1.7.
KV, 70 mm < t ≤ 150 mm, long. / transv., min. average	41 J / 27 J	Table 1.7.

Average of three Charpy specimens; one individual value may be lower, but not less than 70 % of the average (B.6.4). Impact tests are generally not required below 6 mm (B.6.5). Sub-size: 5/6 of the tabulated energy at 10 × 7.5 mm and 2/3 at 10 × 5.0 mm (B.6.3). Delivery condition: Table 1.5: t ≤ 35 mm, any condition; 35 mm < t ≤ 150 mm, normalised, normalising-rolled or TM-rolled. Subject to special approval of GL, sections may be supplied as-rolled if impact results are consistently satisfactory (Table 1.5, note 2).

Available Dimensions

Section 1 B.1.2 is primarily intended for plates and wide flats up to 150 mm thick and for sections and bars up to 50 mm thick, in all of the normal and higher-strength grades. Greater thicknesses may be allowed or required in particular cases after consideration of the technical circumstances. For shipbuilding flat products the permitted lower deviation from nominal thickness is a uniform −0.3 mm (Class B of Table 1.1, B.8). Width, length and any stock programme are as agreed for the order; no stock size is implied here.

Main Applications

GL Grade D (GL-D) is used for welded hull and ship structural members specified to this Germanischer Lloyd grade. Fitness for a given location, thickness and service is set by the contract design and the attending society.

Equivalent Grades of GL-D

Official comparable product pages, where inventoried, are linked below.

Society / standard	Comparable grade	Qualification
ABS	ABS Grade D	Comparison at the same strength and toughness class only.
BV	BV Grade D	Comparison at the same strength and toughness class only.
DNV	DNV Grade D (NV D)	Comparison at the same strength and toughness class only.
LR	LR Grade D	Comparison at the same strength and toughness class only.

Comparison only: not automatic equivalence or substitution. Linked pages state that society’s own requirements, which are not Germanischer Lloyd requirements. The 2009 GL tables on this page are the only GL numerical source used here. No official gangsteel.com product page is inventoried for CCS Grade D or KR Grade D, and none is invented here.

Related Products

Further official Germanischer Lloyd hull-steel pages from Gangsteel:

Frequently Asked Questions (FAQ)

What is GL Grade D (GL-D) steel plate?

GL Grade D (GL-D) is a Germanischer Lloyd hull structural steel in Section 1 B of the 2009 GL II-1-2 chapter. The official designation is GL-D. It is a normal-strength grade (minimum yield 235 N/mm²) in the −20 °C laboratory impact class of Table 1.7, subject to the exemptions shown there.

Does the impact-test temperature define the service limit of GL Grade D (GL-D)?

No. The −20 °C Charpy temperature is a laboratory test condition. Approved service temperature and structural use are set by the ship rules, the design and the attending surveyor.

Can another society’s similarly named grade replace GL Grade D (GL-D) automatically?

No. The Equivalent Grades table is a comparison at the same strength and toughness class, not automatic equivalence or substitution.

Does GL Grade D (GL-D) automatically include through-thickness (Z) properties?

No. Thickness-direction testing applies only when ordered, under Section 1 I of the 2009 chapter. It is not implied by the grade name and is not in these official product titles.

What should an enquiry for GL Grade D (GL-D) include?

State GL Grade D (GL-D), the governing rules edition, dimensions, quantity, delivery condition, inspection documents, and any transverse impact or through-thickness testing required. Availability is confirmed for the enquiry; none is implied here.

Contact Gangsteel with your GL Grade D (GL-D) plate specification and project requirements for an order-specific technical and commercial review. Further GL hull-steel pages are listed on the Germanischer Lloyd shipbuilding steel plates hub and at Gangsteel.