A Comprehensive Analysis of Shipbuilding Steel Grades: From Grade A to FH40, How to Select the Most Suitable Material for Your Vessel?
In the fields of shipbuilding and marine engineering, shipbuilding steel plates are the key materials that determine the safety and lifespan of the ship. However, when many purchasing personnel encounter a series of grade designations such as "A, B, D, E, AH32, DH36, FH40", they often feel confused: What are the differences among them? What are the performance values corresponding to the price differences? Choosing too high a grade leads to waste of costs, while choosing too low a grade may pose safety hazards.
This article will systematically outline the classification system of marine steel plates, helping you quickly understand the classification logic and make safe and cost-effective material selection decisions.
The logical basis for classifying shipbuilding steel grades
The major global classification societies (such as CCS, ABS, LR, DNV, etc.) classify marine steel plates based on a unified logic: strength grade + toughness grade.
These two dimensions jointly determine the applicable position and service environment of the steel plate in the ship structure.
| Grade classification | Key considerations | |
|---|---|---|
| Strength grade | General strength steel / High strength steel / Ultra high strength steel | The magnitude of the load borne determines the carrying capacity of the ship's structure. |
| Toughness level | A,B,D,E,F(Decreasing in accordance with the decreasing impact temperature) | The service environment temperature determines the ability of the steel plate to resist brittle fracture at low temperatures. |
Classified by strength grade
Normal Strength Steel (General Strength Steel)
This is the basic grade of marine steel plates, with codes A, B, D, and E (prefixes do not have "H"). Its yield strength is not less than 235 MPa, and it is suitable for parts of the ship that are subjected to regular stresses.
| Characteristics | Typical application scenarios | |
|---|---|---|
| A | 0°C impact toughness, the most basic ship plate grade | Non-critical load-bearing parts such as the ship's outer shell plating, decks, and bulkheads |
| B | 0°C impact toughness, with the chemical composition controlled to a slightly stricter standard than before A. | The internal structure of the hull, for areas with slightly higher requirements for toughness |
| D | -20°C impact toughness, excellent low-temperature toughness | Side and bottom plating of the hull, suitable for winter routes |
| E | Impact toughness at -40°C and excellent resistance to low-temperature brittle fracture. | Key structural components of the hull, hull of ships operating in ice areas |
High Strength Steel
The code for high strength steel ends with "H", such as AH, DH, EH, and FH. Their yield strength is no less than 315 MPa (Level 32) or 355 MPa (Level 36), and some can reach 390 MPa (Level 40). They can significantly reduce the thickness of the ship's hull plates while ensuring safety, thereby reducing the ship's weight and increasing the cargo capacity.
| Grade | Yield strength (minimum) | Typical application scenarios |
|---|---|---|
| AH32 / AH36 | 315 / 355 MPa | The main structural components of bulk carriers and container ships |
| DH32 / DH36 | 315 / 355 MPa | The high-stress areas at the bottom and sides of the hull, with both low-temperature toughness |
| EH32 / EH36 | 315 / 355 MPa | Key nodes of polar navigation vessels and offshore engineering platforms |
| FH32 / FH36 / FH40 | 315 / 355 / 390 MPa | Extreme working conditions areas of submarines, ice-breaking ships, and super-large container ships |
Classified by resilience level (impact temperature)
This is the dimension that is most easily overlooked but is of crucial importance in the selection of marine steel plates. For the same strength grade, different toughness grades correspond to different minimum service temperatures.
| Grade | Impact test temperature | Applicable environment |
|---|---|---|
| A | 0°C | Tropical and temperate sea areas, conventional navigation environment |
| B | 0°C | Conventional structures with a slight requirement for resilience |
| D | -20°C | Winter routes in the North Sea and the North Atlantic |
| E | -40°C | Arctic routes, ice area navigation, extremely cold environment |
| F | -60°C Or even lower | Polar research vessels, LNG ship inner liner support structure |
Common Comparison Table of Shipbuilding Steel Grades
| Grade | Toughness level | Yield strength(MPa) | Impact temperature(°C) | Ship plate code |
|---|---|---|---|---|
| General strength | A | ≥235 | 0 | CCS A |
| General strength | B | ≥235 | 0 | CCS B |
| General strength | D | ≥235 | -20 | CCS D |
| General strength | E | ≥235 | -40 | CCS E |
| High intensity(32kg) | A | ≥315 | 0 | CCS AH32 |
| High intensity(32kg) | D | ≥315 | -20 | CCS DH32 |
| High intensity(32kg) | E | ≥315 | -40 | CCS EH32 |
| High intensity(36kg) | A | ≥355 | 0 | CCS AH36 |
| High intensity(36kg) | D | ≥355 | -20 | CCS DH36 |
| High intensity(36kg) | E | ≥355 | -40 | CCS EH36 |
| Ultra-high strength(40kg) | F | ≥390 | -60 | CCS FH40 |
How to select the appropriate marine steel plates for your project?
In actual procurement, we suggest considering the following four aspects comprehensively:
Ship shape and structural components
Bulk carriers and oil tankers: AH32 / AH36 are the mainstream choices, balancing strength and economy.
At the bottom of the hull and the turning points of the sides: It is recommended to use DH32 / DH36. These areas have concentrated stress and require better low-temperature toughness.
Hatch covers and bulkheads: Ordinary strength steel (Grade A/B) is sufficient to meet the requirements.
Navigation route
For tropical or temperate waters only: Grade A or Grade AH is sufficient.
Regarding the winter conditions in the North Sea and the North Atlantic: It is recommended to upgrade to the D class or DH class.
Arctic shipping routes or navigation in ice zones: It is necessary to select Class E or higher, and in some cases, Class F should also be considered.
The classification society requires
Different classification societies have specific regulations for the steel grades of certain ship types. Before selecting materials, it is recommended to refer to the "Ship Classification Specifications" of the corresponding classification society, or to consult our technical team. We can provide free material selection advice.
The balance between cost and performance
High-strength steel (such as AH36) although has a higher unit price than general strength steel (such as grade A), due to its higher yield strength, it allows the use of thinner steel plates, thereby:
Reduce the weight of the ship and increase the cargo capacity
Reduce the welding workload and shorten the ship berth cycle
The overall cost might actually be lower.
who choose us?
Full range coverage: From CCS A to FH40, we have stable supply sources for all.
Multi-class certification: CCS, ABS, LR, DNV, NK, BV - all available.
Fixed-length cutting service: Process according to the drawings, reducing your on-site workload
Complementary warranty documents: Original warranty certificate + Ship Inspection Certificate, ensuring a successful first-time ship inspection.
one-stop solution
professional team
high quality
Choose YUXIN steel group, and what you purchase is not merely the steel plates, but also a complete warranty system and a sense of responsibility.
Our address
Tianjin, China
Phone Number
(86)-15937221771(WeChat)
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info@chinasteelcompany.com
FAQ
01.How are the names of the ship plates determined? For example, what does CCS A mean?
A: Indicates that the strength level is of general strength. The general strength steel plates are divided into four grades: A, B, D, and E. The main difference lies in the test temperature for impact toughness (grade A at 0°C, grade B at 20°C, grade D at -20°C, and grade E at -40°C).
02.When purchasing the ship plates, what documents can you provide?
Traceability: The furnace number and batch number on the certificate must be consistent with the physical markings on the steel plate.
Data: It must include actual measured data such as chemical composition, mechanical properties (yield, tensile strength, impact value), etc.
03.What is the minimum order quantity?
04.Can you provide cutting and processing services?
China one-stop steel processing procurement
Through years of understanding and precipitation of steel, Yuxin Group has now become a mature steel processing and manufacturer, providing various products for many construction companies and steel structure companies around the world. Thanks to Yuxin Group's professionalism and integrity, it has become a world-renowned enterprise.
