Description: BBN steel is a well-known steel manufacturer and service provider in China, Shipbuilding and Offshore Platform steel plate is our superior product, we are favored by customers with high quality, competitive price and excellent service
Payment Terms: L/C, T/T, D/P, Western Union, Paypal, Money Gram
ASTM A131 marine steel for hull structures, offshore platforms, cruise ship cabins and oil & gas vessels.
GradesA / B / D / E · AH32–FH40 · AQ47–FQ70
Thickness3–150 mm
Width1220–4200 mm
Length5000–18000 mm
Class approvalABS · LR · DNV · BV · CCS · KR · NK · RINA · GL · RMRS
Three strength levels — ordinary A/B/D/E, high strength AH32–FH40, extra high strength AQ47–FQ70, all from one mill programme.
Thin wide to heavy plate — flatness-controlled plate for cruise ship cabins, TMCP plate for offshore structures.
Certified to your project — society certification arranged to your specification, vessel flag and inspection plan.
01Product Overview & Specifications
Shipbuilding and offshore platform steel plate is the structural backbone of every vessel and marine installation. BBN Steel supplies the full range of ASTM A131 marine grades — common strength (A, B, D, E), high strength (AH32 to FH40) and extra high strength (AQ47 to FQ70) — with certification from the world’s leading classification societies.
Selection is driven by service temperature and structural load: ordinary grades serve general hull structure, high strength grades reduce plate weight in large hulls and topsides, and extra high strength quenched & tempered grades carry the concentrated loads of offshore platform superstructures, jack-up legs and heavy oil & gas equipment. Thin, wide plate with controlled flatness is produced specifically for cruise ship cabin structures where weldability and surface quality decide the fabrication cost.
3–150 mmThickness RangeThin wide plate to heavy offshore section
1220–4200 mmWidth RangeLength 5000–18000 mm
32ASTM A131 GradesCommon · high · extra high strength
10Classification SocietiesABS · LR · DNV · BV · CCS · KR · NK · RINA · GL · RMRS
Item
Specification
Product
Shipbuilding and Offshore Platform steel plate — marine and offshore structural steel
Standard
ASTM A131 / A131M, supplied to classification society rules
Strength Levels
Common strengthHigh strengthExtra high strength
Thickness
3 – 150 mm
Width
1220 – 4200 mm
Length
5000 – 18000 mm
Custom Sizes
Available on request — supply thickness, width, length and quantity with your inquiry
Delivery Condition
Hot rolledThermo-mechanically rolled (TMCP)NormalizedQuenched & tempered as required by grade and thickness
Surface Treatment
Hot rolledCoatedShot blasting and paintingPrimer coating on request
Mill Test Certificate with classification society certification — ABS, LR, DNV, BV, CCS, KR, NK, RINA, GL, RMRS
Processing Service
Shot blasting and paintingCutting to sizeWelding serviceProcessing to drawings
Sizing note: the ranges above are the standard supply envelope for our shipbuilding plate programme. Plates outside these limits, and non-standard width/length combinations, can be reviewed against mill capability — send the required dimensions together with the grade and classification society so we can confirm the rolling programme.
02Main Steel Grades & ASTM A131 Grade Range
Three strength families cover every marine and offshore application. Click any grade to open its dedicated page with full mechanical properties, chemical composition and certification details.
Offshore platform superstructures, jack-up and heavy lift structures, special vessels and high-loaded oil and gas equipment
Q51
AQ51DQ51EQ51FQ51
Q63
AQ63DQ63EQ63FQ63
Q70
AQ70DQ70EQ70FQ70
How to select: the leading letter fixes the impact test temperature, the number fixes the minimum yield strength, and H / Q fix the strength family (high strength / extra high strength, quenched & tempered). See section 03 for the full decoding, or send us the service temperature and plate thickness and we will recommend the grade.
03Grade Designation & Strength Classes
An ASTM A131 designation is a compact specification: it tells you the toughness class, the strength family and the minimum yield strength before you open a single data sheet.
A–F
Leading Letter = Toughness Class
The first letter sets the Charpy V-notch impact test temperature: A / B / D / E / F step down in temperature, so the same strength level can be ordered for tropical, temperate, winter or polar service.
H
H = High Strength
H marks the high strength hull structural grades (AH32, DH36, EH40 …). These are normally thermo-mechanically rolled (TMCP) to reach the yield level at low carbon equivalent, keeping weldability.
32–40
Number = Min. Yield in ksi
32 / 36 / 40 give the minimum yield strength in ksi — about 315 / 355 / 390 MPa. Higher numbers mean thinner plate for the same load, i.e. less hull weight.
Q
Q = Extra High Strength
Q grades (Q47 / Q51 / Q63 / Q70) are the extra high strength, quenched & tempered family — roughly 460 / 500 / 620 / 690 MPa minimum yield for the most heavily loaded offshore sections.
Strength Family
Designation
Min. Yield (MPa, approx.)
Typical Supply Condition
Common strength
A / B / D / E
235
As rolled / normalized
High strength
AH32 / DH32 / EH32 / FH32
315
TMCP / normalized
High strength
AH36 / DH36 / EH36 / FH36
355
TMCP / normalized
High strength
AH40 / DH40 / EH40 / FH40
390
TMCP / normalized / Q&T
Extra high strength
AQ47 / DQ47 / EQ47 / FQ47
460
Quenched & tempered
Extra high strength
AQ51 / DQ51 / EQ51 / FQ51
500
Quenched & tempered
Extra high strength
AQ63 / DQ63 / EQ63 / FQ63
620
Quenched & tempered
Extra high strength
AQ70 / DQ70 / EQ70 / FQ70
690
Quenched & tempered
Impact toughness — the letter fixes the guaranteed Charpy V-notch test temperature:
Leading Letter
Common Strength Grades
High / Extra High Strength Grades
Charpy V-Notch Test Temperature
A
A
—
+20°C
B
B
AH…
0°C
D
D
DH…
−20°C
E
E
EH…
−40°C
F
—
FH…
−60°C
Important: the yield levels and impact test temperatures above are the conventional ASTM A131 / IACS reference values used for grade selection. Actual required values depend on grade, thickness range, heat treatment condition and the rule of the classification society (ABS, DNV, LR, BV, CCS, KR, NK, RINA, GL or RMRS). Always confirm the binding figures against the approved specification and the Mill Test Certificate of the delivered heat.
04Typical Applications
Shipbuilding plate is used across the whole marine and offshore engineering chain — from thin, wide cabin plate to quenched & tempered sections carrying concentrated offshore loads.
Hull Structure
Shell plating, bottom and side shell, decks, bulkheads and superstructures. Common strength A / B / D / E for general hull areas, high strength AH/DH/EH grades where plate weight and section size must be reduced.
Offshore Platform
High strength thermo-mechanically rolled plate for platform superstructures, topside modules, jackets, jack-up legs and deck structures, where yield level and through-thickness quality drive the design.
Cruise Ship Cabin Structure
Especially thin but wide plate for cabin and accommodation structures, supplied with controlled flatness and weldability so panels can be welded with minimal distortion and fairing work.
Special Vessels
Plate for special-purpose ships and marine equipment that combine high strength with low-temperature toughness — D, E and F grades for winter, high-latitude and ice-class service.
Oil & Gas Equipment
Extra high strength Q grades and heavy plate for equipment used in the oil and gas industry — process modules, lifting and support structures, drilling and production equipment on vessels and platforms.
Low-Temperature & Ice Service
E and F grades with guaranteed low-temperature impact toughness for ice-class hulls, polar and high-latitude operation, and structures exposed to low ambient temperature.
05Surface Treatment, Testing & Processing
Marine and offshore projects specify more than a grade. Surface condition, through-thickness quality and pre-fabrication are handled in-house so plates arrive ready for your production line.
Item
Available Options
Surface Treatment
Hot rolledCoatedShot blasting and paintingPrimer coating upon request
Testing & Inspection
Ultrasonic examinationNormalizingQuenching and temperingZ-direction test Z15 / Z25 / Z35Third-party inspection by end user or project owner
Additional Processing
Shot blasting and paintingCutting to sizeWelding serviceProcessing to customer drawings
1
Shot Blasting & Painting
Mill scale removed and shop primer applied so plates can go straight to cutting and welding.
2
Cutting to Size
Plates cut to your nesting plan or drawing, reducing scrap and handling at your yard.
3
Welding Service
Welding carried out to your procedure specification by qualified welders.
4
Processing to Drawings
Processing according to customer drawings or project specifications, including bevels and hole patterns.
Z-direction testing: through-thickness (short transverse) reduction of area testing to Z15, Z25 or Z35 is available for highly restrained joints such as node connections, jack-up legs, heavy topside nodes and crane pedestals. Specify the required Z quality with your inquiry — it is verified on the MTC.
06Classification Society Certification
A hull structure only enters service once a classification society has signed off the steel behind it. Our marine and offshore plates are produced, inspected and surveyed to the rules of the ten societies below, and the certification is issued for your specific project — not quoted from a generic stock list.
Marine & Offshore Class Approval
Supplied With Certification From 10 Classification Societies
Every order is surveyed against the applicable rule set and rule year, covering chemical composition, yield and tensile strength, elongation, Charpy V-notch impact testing at the specified temperature, heat-treatment condition and dimensional tolerances. The certificate travels with the plate as part of the documentation package, so the steel moves cleanly through plan approval, class survey and owner inspection.
ABSUnited States
LRUnited Kingdom
DNVNorway
BVFrance
CCSChina
KRSouth Korea
NKJapan
RINAItaly
GLGermany
RMRSRussia
The societies we certify to, and where each one is normally required
Different flags, different yards, different trades — each tends to name its own society. Tell us which one your project specifies and we will confirm the approval scope covers the grade, thickness range and delivery condition before the plate is rolled.
ABSUSA · est. 1862
American Bureau of Shipping
The leading society for US-flag tonnage and for offshore units worldwide — jack-ups, semi-submersibles, FPSOs and MODUs — where its offshore rules are the default reference for both hull structure and topsides.
LRUnited Kingdom · est. 1760
Lloyd’s Register
The oldest classification society. Its Rules and Regulations for the Classification of Ships are widely referenced for merchant tonnage, naval auxiliaries, ice-class vessels and the large cruise newbuildings that demand thin, wide, high-flatness plate.
DNVNorway · est. 1864
Det Norske Veritas
Now the rule baseline most often quoted for offshore platforms, floating production units and subsea structures, and routinely named on North Sea and Norwegian-shelf work, where a High strength designation such as AH36 or EH36 pairs with low-temperature toughness.
BVFrance · est. 1828
Bureau Veritas
Strong coverage of LNG and gas carriers, tankers, container tonnage and cruise vessels, backed by one of the largest industrial inspection networks — convenient when the same inspector handles steel, equipment and topsides.
CCSChina · est. 1956
China Classification Society
The national class society of the PRC and the usual requirement for vessels and offshore modules built in Chinese yards — bulk carriers, barges, dredgers, wind-farm service vessels and FPSO conversion and repair work.
KRSouth Korea · est. 1960
Korean Register
Standard specification for tonnage out of Korean yards — bulk carriers, VLCCs and LNG carriers — and frequently named again when those vessels later trade, are re-flagged or are reclassified.
NKJapan · est. 1899
Nippon Kaiji Kyokai (ClassNK)
Japan’s national class society and the conventional requirement for Japanese-built merchant tonnage and Japanese-owned fleets; also active across the wider Asian shipbuilding and repair hubs.
RINAItaly · est. 1861
Registro Italiano Navale
Commonly specified on Italian-built tonnage — cruise ships, ro-pax ferries, yachts and naval auxiliaries — where its rules sit alongside European harmonised requirements for passenger safety and fire protection.
GLGermany · est. 1867
Germanischer Lloyd
Germany’s historic class society, merged with DNV in 2013 and now carried on within DNV. GL approval remains in force for existing tonnage, and we still support projects that specify the legacy GL rule set.
RMRSRussia · est. 1913
Russian Maritime Register of Shipping
The reference for Russian-flagged tonnage, river–sea ships and especially ice-going and Arctic service vessels, where high-priority requirements are ice class strengthening and toughness at low temperatures.
On DNV and GL — Germanischer Lloyd merged with Det Norske Veritas in 2013 and today operates as part of DNV. Plates that historically carried GL certification remain valid for existing vessels. For new projects, tell us whether you want the current DNV notation or the legacy GL designation, and we will quote to whichever the project documentation demands.
How the certification is arranged
1
Society, flag & rule year confirmed first
Before rolling we check that the mill’s approval scope covers your grade, thickness range, Z quality and delivery condition.
2
Mill survey & witnessed testing
Tensile, yield, elongation and Charpy V-notch impact tested to the specified temperature; UT and Z15 / Z25 / Z35 added where required.
3
Certificate & full traceability
Society surveyor release note or certificate issued against heat number, so every plate traces back to its cast and test record.
4
Owner / third-party inspection
Inspection arranged by the end user, project owner or nominated agency can be supported at the mill alongside class survey.
Certification can be arranged according to the customer’s project requirements — tell us the society, the flag and the rule year and we will match the approval scope before rolling.
07Frequently Asked Questions
Q1Which classification societies can you certify shipbuilding plate against?
We supply marine and offshore steel plate with certification from ABS, LR, DNV, BV, CCS, KR, NK, RINA, GL and RMRS. Certification is arranged according to your project requirements, including the applicable rule year and approval scope, and is documented in the Mill Test Certificate.
Q2What plate sizes are available?
Standard supply range is 3–150 mm thickness, 1220–4200 mm width and 5000–18000 mm length. Custom sizes may be available upon request — send the required dimensions with the grade and quantity and we will confirm against the mill rolling programme.
Q3Which grades do you supply, and how do I choose between AH36, DH36 and EH36?
All three strength families are available: common strength A, B, D, E, high strength AH32–FH40 and extra high strength AQ47–FQ70. The letter sets the impact test temperature — AH36 is tested at 0°C, DH36 at −20°C and EH36 at −40°C — so the choice is driven by the lowest service temperature of the structure. Click the grade in section 02 for its full data sheet.
Q4We need thin, wide plate for cruise ship cabin structures — what about flatness and weldability?
Especially thin but wide plate is produced specifically for cabin and accommodation structures, with controlled flatness and weldability to keep distortion and fairing work low during panel fabrication. Tell us the panel dimensions and the welding procedure and we will confirm the flatness tolerances and supply condition.
Q5Can you provide ultrasonic examination and Z-direction (Z15 / Z25 / Z35) tested plate?
Yes. Ultrasonic examination and Z-direction testing to Z15, Z25 or Z35 are available, together with normalizing and quenching & tempering where the grade and thickness require it. Third-party inspection arranged by the end user or project owner is also supported.
Q6What information do you need to quote a marine or offshore project?
Please provide the steel grade, the classification society, the plate size (thickness × width × length), the quantity, the delivery condition and the inspection requirements (UT level, Z quality, third-party inspector). With those six items we can return price, production lead time and certification scope.
Get Your Shipbuilding & Offshore Plate Quotation
Send us your steel grade, classification society, plate size, quantity, delivery condition and inspection requirements. We will reply with available sizes, certification scope, competitive mill price and production lead time.
BBN Steel has established a complete set of production and supplier management system processes to ensure the improvement of product quality and better service to users.
Production Control
BBN Steel has established a complete production quality control process to ensure every link from research and development to mass production.
Supplier management
Our supplier selection will consider factors such as health and safety, ethics, environmental protection, price and quality to better serve customers.
Certification & Patent
We have successively won various international authoritative certifications, GB /T19001-ISO9001: 2000 quality management system was implemented.
After sales service
We provide booking space, shipping tracking service and after-sales service, we will always be first-class products and perfect pre-sale and after-sales service.
Get in Touch
Welcome to contact us through online consulting, emails and hotline if you are interested in our company or products. Our staff will reply you within 24 hours.
Address: HIGH-TECH DEVELOPMENT ZONE, ZHENGZHOU, CHINA
