Inquiry Now

LR Grade D Shipbuilding Steel Plate - Ordinary-Strength Low-Temperature-Resistant Marine Structural Steel

info@yx-steel.com 8615837212056 Get a Quote

LR Grade D shipbuilding steel plates are high-performance marine structural steels of ordinary strength and low-temperature resistance that comply with LR classification society specifications. They offer excellent low-temperature toughness, weldability, and corrosion resistance, making them suitable for ocean-going vessels operating in cold waters and offshore engineering projects. We offer a full range of LR-certified products and provide custom processing, UT testing, and third-party inspection services. With our stable supply capabilities, we deliver reliable steel solutions to shipyards and offshore engineering projects worldwide.

Certification :
LR Rules
Grade :
LR Grade D (LR D)
Thickness :
5.0 - 150.0 mm
Width :
1500.0 - 4000.0 mm
Length :
6000.0 - 18000.0 mm

Special thickness, width, and length can be negotiated separately.
We also provide customized processing services.If you have any questions, please contact us.

Overview

1. What is LR Grade D shipbuilding steel plate?

LR Grade D is a Lloyd’s Register (LR)-certified ordinary-strength hull structural steel plate for low-temperature applications, with a yield strength of ≥235 MPa, a tensile strength of 400 - 520 MPa, and has passed the -20°C Charpy V-notch impact test.

Compared to LR Grade A and Grade B, its key advantage lies in its impact toughness at -20°C, which effectively reduces the risk of brittle fracture in cold waters.

Manufactured using advanced smelting and controlled rolling processes, this steel plate offers excellent strength, weldability, structural stability, and resistance to seawater corrosion. Thanks to its good low-temperature performance and cost-effectiveness, it is widely used in vessels operating in high-latitude waters, deep-sea engineering, and marine projects in cold climates.

2. Meaning of the Designation

LR: Certified by Lloyd’s Register (LR)

D: Quality grade B (Must meet the requirements of the impact test at -20°C)

Available Specifications and Dimensions

Product Name	LR Grade B Shipbuilding Steel Plate
Certification	LR (Supports third-party certification by SGS, BV, DNV, ABS, CCS, and others.)
Grade	LR D
Classification	Ordinary-Strength Structural Steel for Ship and Ocean Engineering
Thickness	5 - 150 mm
Width	1500 - 4000 mm
Length	6000 - 18000 mm
Delivery Conditions	Hot Rolled (HR), Thermo-Mechanical Controlled Processed (TMCP), Normalized (N), Quenched and Tempered (Q+T).
Surface Conditions	Original black oxide layer, No cracks, scarring, delamination, inclusions, or deep scratches.
Machining Services	Precision cutting, bending, drilling, beveling, surface rust removal, shot blasting, anti-corrosion coating, and customized secondary processing.
Inspection	Charpy V-notch impact test, Ultrasonic testing (UT), Z-direction property test (Grades Z15/Z25/Z35), Third-party test (such as SGS), etc.
Applications	It is primarily used for the hulls, decks, and sides of vessels operating in cold seas; for offshore engineering structural components in low-temperature environments; and for coastal infrastructure and ship repair and retrofitting in cold regions.
MOQ	5 tons (small orders can be negotiated).
Delivery Time	15 - 20 days after order confirmation (urgent orders accepted)
Packaging	Standard export packaging for sea transport, or as required.
Country of origin	China

Chemical Composition

Chemical Composition (Heat Analysis, wt %)

Grade	C	Si	Mn	P	S	Cu	Cr	Ni	Als
LR D	≤ 0.21	≤ 0.35	≥ 0.60	≤ 0.030	≤ 0.030	≤ 0.35	≤ 0.30	≤ 0.30	≥ 0.015

Carbon Equivalent (wt %)

Thickness (mm)	5 - 50	50 - 150
Typical CEV (wt %)	≤ 0.38	≤ 0.40

Calculation formula (IIW): CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15

Mechanical Properties

Tensile test

Grade	Yield Strength (ReH), MPa	Tensile Strength (Rm), MPa	Elongation (A), %
LR D	≥ 235	400 - 520	≥ 22

Charpy (V-notch) impact test

Grade	Thickness, mm	Temperature, ℃	Impact Energy, KV₂ / J
Grade	Thickness, mm	Temperature, ℃	Longitudinal	Transverse
LR D	≤ 50	- 20	≥ 27	≥ 20
	> 50 - 70	- 20	≥ 34	≥ 24
	> 70 - 150	- 20	≥ 41	≥ 27

Applications

LR Grade D shipbuilding steel plates are widely used in shipbuilding for cold regions and in the field of cryogenic offshore engineering, covering project requirements such as seagoing vessels for cold regions, deep-sea support facilities, cryogenic coastal infrastructure, and ship retrofits.

I. Applications in Ship Hull Structures

1. Applicable Ship Types

a) Ocean-going dry cargo ships, bulk carriers, small- and medium-sized oil tankers, container ships, general cargo ships, tugs, supply vessels, and inland waterway/coastal vessels under 1,000 metric tons;

b) Vessels operating in the North Atlantic, high-latitude regions, and winter low-temperature routes.

2. Specific Hull Components

a) Bow Area: Bow outer plating, stem, bow side, and bow rib framework;

b) Side Plating: Side hull plating for cold-water regions, double-layer side structures;

c) Deck Systems: Open main deck, superstructure deck, deck beams, stringers, and deck cover plates;

d) Bulkheads and Cargo Holds: transverse bulkheads, longitudinal bulkheads, cargo hold sides, ballast tank bulkheads, general liquid cargo tank shells;

e) Double Bottom: double bottom plates for vessels operating in cold-water routes, inner bottom plates, bottom stringers;

f) Superstructure: Bridge, engine room canopy, outer walls of the accommodation deck, bulkheads, stair landings;

g) Secondary load-bearing components: Struts, frames, stiffeners, brackets, fender structures, and auxiliary bottom materials;

h) Ship repair: Replacement of aged hull plates on ships operating in cold regions, and emergency repairs to damaged outer plates.

II. Applications in Offshore Engineering Platforms

a) Fixed offshore drilling platforms: platform decks, walkways, guardrails, platform ancillary structures, pipe joint reinforcement plates, and secondary support beams;

b) Floating equipment: secondary structures of FPSO hulls, offshore work barges, and crane ship hulls;

c) Steel plates for offshore wind turbine foundations, auxiliary floating structures for offshore construction, and protective casings for subsea pipelines.