Asia’s shipyards are operating at full capacity. Their new orders require specific, efficient materials. This is directly fueling a surge in demand for one critical component: bulb flat steel.

Bulb flat steel, also known as bulb plate, is experiencing significant demand growth in Asian shipyards. This is driven by the region’s dominance in constructing large, modern container ships and bulk carriers, where this profile is essential for building strong yet lightweight transverse frames and stiffeners.

I see this trend clearly in our order books. Inquiries from Vietnam, the Philippines, and Thailand for bulb flats have increased sharply this year. The reason is simple. Asian yards are winning the contracts for the most advanced vessels. These vessels need materials that save both weight and labor. Bulb flat steel does exactly that. But to understand why this specific product is booming, we need to look at the bigger picture of steel in shipbuilding.

What is the use of flat steel¹?

You see a ship’s smooth hull. Behind that smooth surface is a skeleton. Flat steel forms the basic bones and ribs of that skeleton, providing the essential framework for the entire vessel.

Flat steel is primarily used to fabricate the internal structural framework² of a ship. This includes frames, stiffeners³, and longitudinals that reinforce the hull plating, decks, and bulkheads, giving the vessel its structural integrity and resistance to bending and twisting forces at sea.

The Backbone of the Ship: More Than Just a Flat Piece

When people think of ship steel, they often picture the thick hull plates. But the flat steel¹ working behind the scenes is equally vital. Its use is about creating an efficient, lightweight grid system. The hull plate is like the skin. The flat steel¹ profiles are the ribs and spine. They prevent the thin skin from buckling under the immense pressure of water and cargo.

Primary Functions in Structure:

1. Stiffening: The main job of flat steel¹ bars is to act as stiffeners³. They are welded perpendicular to frames or longitudinals. This creates a grid that dramatically increases the panel’s resistance to deformation. A large, flat area of hull plate with no stiffeners³ would bend easily. Add a network of flat steel¹ stiffeners³, and it becomes rigid.
2. Frame Construction: Ships have vertical frames that run from the keel to the deck. These frames are often built using a combination of steel plates and flat steel¹. The flat steel¹ can form the web (the vertical part) of a built-up frame section.
3. Brackets and Connections: Flat steel is cut and shaped to make countless brackets, gussets, and connecting pieces. These small parts are crucial for joining larger structural members together securely.

The Evolution to Bulb Flat Steel:
Traditional flat steel¹ has a simple rectangular cross-section. But a major innovation changed shipbuilding: the bulb flat. A bulb flat is a flat steel¹ bar with a thickened, rounded edge (the "bulb") along one of its longer sides. This small change has a big impact.

The bulb provides extra material exactly where it is needed most—away from the neutral axis of the beam. This gives the profile a much higher section modulus with only a small increase in weight. In practical terms, a bulb flat can replace a much heavier built-up section made from a flat bar and an angle. This leads to direct weight savings for the ship.

Why This Matters for Asian Shipyards Now:
Asian shipyards⁴ in China, South Korea, and Japan are the global leaders in building large container ships and LNG carriers. These ship types are under extreme pressure to be efficient. Every ton of steel saved is a ton of extra potential cargo, or a ton less fuel burned. Therefore, these yards have fully adopted bulb flat steel⁵l](https://cnmarinesteel.com/the-role-of-bulb-flat-steel-in-ship-hull-reinforcement/)[^1] as the standard for transverse framing. They design with it from the start. The surge in orders for these large vessels directly translates into a surge in orders for bulb flats. The use of standard flat steel¹ persists for smaller vessels, secondary structures, and repair work. However, for the high-value, high-efficiency newbuilds that define the market today, bulb flat steel⁵l](https://cnmarinesteel.com/the-role-of-bulb-flat-steel-in-ship-hull-reinforcement/)[^1] is the undisputed choice for critical stiffening applications. This shift in application preference is a key driver of the current demand growth we are witnessing.

Will steel demand¹ increase in 2025?

Shipowners are placing orders now for delivery in 2025 and beyond. The current orderbook² in Asian yards is strong, and new regulations are forcing fleet renewal³. This points to continued demand.

Yes, overall steel demand¹ for shipbuilding is expected to increase in 2025. This growth is supported by a full orderbook² at major Asian shipyards, a continued need for more environmentally efficient vessels, and ongoing replacements in aging global fleets, all requiring substantial tonnage of marine steel.

Analyzing the 2025 Outlook: A Mixed Picture with Clear Growth Drivers

Predicting steel demand¹ is complex. We must look at different signals. My view, based on daily conversations with mills and clients, is that demand will grow, but the growth will be specific. It will not be a boom for all types of steel. The demand will be strongest for the steel used in the specific ships that yards are building.

Positive Drivers for Increased Demand:

1. The Existing Orderbook: This is the most concrete factor. Major shipyards in China, Korea, and Japan have full schedules stretching into 2026. These contracts are signed. They require steel. The steel for ships to be delivered in 2025 will be mostly ordered and produced in 2024. This creates a solid baseline of demand.
2. The IMO Regulatory Push⁴: The IMO’s Carbon Intensity Indicator (CII) and Energy Efficiency Existing Ship Index (EEXI) are not one-time events. They create ongoing pressure. Older, inefficient ships become economically unviable. This drives orders for new, efficient replacements. This "regulatory replacement cycle" is a multi-year trend that supports demand.
3. Strategic Fleet Expansion: Some nations and shipping companies are expanding their fleets for strategic or trade reasons. For example, demand for LNG carriers⁵ remains high due to global energy security concerns. Each large LNG carrier requires over 40,000 tons of high-quality steel.

Potential Challenges and Uncertainties:

1. Economic Volatility: Global economic growth directly affects trade volumes. If trade slows, the urgency for new ships may soften. However, the current orderbook² provides a buffer against short-term economic dips.
2. Steel Price Fluctuations: The price of iron ore, coking coal, and energy affects steel prices. Sharp increases can make newbuilds more expensive and potentially delay some investment decisions.
3. Shipyard Capacity: There is a limit to how many ships can be built at once. Labor, crane, and dock space are finite. This capacity constraint might cap the number of new orders that can be placed for 2025 delivery, indirectly affecting the rate of new steel demand¹ generation.

Demand by Steel Product Type:
The overall increase will not be even. We should expect stronger growth for advanced products⁶.

My On-the-Ground Insight:
Our mill partners in Shandong are planning their 2025 production schedules now. Their discussions are focused on allocating more capacity for higher-strength plates and bulb flats. They are receiving more inquiries with these specifications. This is a leading indicator. When mills adjust their product mix, it is because their customers—the fabricators and yards—are telling them what they will need. The feedback from our clients, like the project distributor in Saudi Arabia, is that their own clients are planning projects for 2025 that specify advanced materials. Therefore, while macroeconomic headlines may cause uncertainty, the specific, project-driven demand in the marine steel niche looks robust for 2025. The key for buyers is to plan their procurement early to secure supply from mills with the right product mix.

What does flat steel¹ mean?

In a shipyard, "flat steel¹" has a very specific meaning. It is not just any flat piece of metal. It refers to a standardized, long product with a simple rectangular cross-section², ready to be cut and welded into the ship’s framework.

In shipbuilding and steel trading, "flat steel¹" specifically refers to a long, flat-rolled steel product with a rectangular cross-section². It is characterized by its width and thickness, and it is supplied in straight lengths or coils³. It is a fundamental raw material for fabricating stiffeners, brackets, and other structural components.

Demystifying the Term: Dimensions, Standards, and Distinctions

Understanding what "flat steel¹" means requires clarity on its form, how it is measured, and how it differs from other similar products. This clarity prevents costly mistakes in ordering and fabrication.

The Physical Definition:
A flat steel¹ bar is exactly what it sounds like. Imagine a long metal ruler. Its cross-section is a simple rectangle. The two key dimensions are:

• Thickness (t): This is the smaller dimension, typically ranging from 3mm up to over 50mm for very heavy bars.
• Width (w): This is the larger dimension, which can range from about 10mm to over 300mm.
  The product is defined as "Width > Thickness." When the width is very large (e.g., 1500mm) and it is supplied in discrete sheets, it is called a "steel plate⁴." The line between very wide flat bar and plate can be blurry, but the term "flat steel¹" in day-to-day shipyard talk usually refers to the bar product.

How It is Supplied:
Flat steel is supplied in two main forms:

1. Straight Lengths (Bars): These are cut to specific lengths, usually 6m, 9m, or 12m. This is the most common form for shipbuilding, as the bars are cut and fitted directly.
2. Coils: Thinner flat steel¹ can be supplied in coils³. This is less common for primary ship structures but may be used for certain automated fabrication processes.

Why the Precise Definition Matters for Buyers:
When you order flat steel¹, you must specify three things: Grade, Thickness, and Width.

• Example Order: "50 MT of Grade AH32 Flat Steel⁵, 12mm thick x 100mm wide, in 12m lengths."
  If you only say "flat steel¹," you will get questions from any professional supplier. The width and thickness determine the steel’s stiffness and strength. Using a 10mm x 50mm flat bar where a 12mm x 100mm is needed would lead to a structural failure.

Flat Steel vs. Plate vs. Bulb Flat: A Crucial Comparison:
Confusion between these terms is common. Let’s break it down:

My Advice from Handling Orders:
I recall a client from Pakistan who once sent an inquiry just for "flat steel¹." Our sales rep immediately called them. We asked for the drawing or specification. It turned out they needed bulb flats for ship frames, not standard flat bars. This early clarification saved weeks of potential back-and-forth and ensured they received the right product quote from the beginning. The term "flat steel¹" is the starting point. As a buyer, you need to be ready to provide the next level of detail: the exact profile shape and dimensions you need. This precision ensures you get a fit-for-purpose material and a smooth procurement process.

What is the steel demand¹ in 2030?

Looking to 2030 is about seeing the long-term waves, not the short-term ripples. Major global commitments will reshape entire fleets, setting a clear direction for steel demand¹.

Steel demand for shipbuilding towards 2030 is projected to remain strong, driven by the industry’s long journey to meet the IMO’s 2030 decarbonization targets². This will require both new, optimized vessels and retrofits, sustaining demand for advanced marine steel grades³ and efficient profiles like bulb flats⁴.

The 2030 Horizon: A Decade of Transformation and Sustained Need

The year 2030 is not just another year. It is a major checkpoint set by the International Maritime Organization (IMO). The IMO aims to reduce the carbon intensity of international shipping by at least 40% by 2030 compared to 2008 levels. This single goal is the central force that will shape steel demand¹ for the rest of this decade.

The Dual Pathways to 2030: Newbuilds and Retrofits.
Demand will come from two main streams:

1. Newbuild Vessels (The Replacement Fleet): A significant portion of the global fleet is old. These older ships cannot meet the 2030 CII standards economically. They will be scrapped. This creates a continuous replacement cycle. The new ships built between now and 2030 will be the most efficient in history. Their designs will maximize the use of high-strength steel and weight-saving profiles like bulb flats⁴ to achieve low carbon intensity from day one. This stream creates high, sustained demand for advanced steel products.
2. Retrofits and Modifications (The Existing Fleet): Not all ships will be scrapped. Some will be modified to improve efficiency. This includes installing energy-saving devices (like new rudders or air lubrication systems), which require steel fabrication. It may also involve "slow steaming" adaptations. Retrofits create a different type of demand: often smaller batches, more varied in specification, and requiring steel that can be welded to existing structures. This supports demand for standard grades but with a high need for precise quality and certification.

Key Demand Drivers Specific to 2030:

• Green Fuel Transition: By 2030, we will see more ships capable of using alternative fuels like methanol, ammonia, or LNG. These vessels require special steel types. For example, tanks for ammonia or LNG need extremely low-temperature toughness (grades like EH36/FH36 and beyond). Demand for these special alloy and high-toughness steels⁵ will grow.
• Material Innovation: The push for efficiency will accelerate the adoption of new materials and composites. However, steel will remain the primary structural material due to its strength, cost, and recyclability. The demand will shift further toward steel that works best with new technologies (e.g., steel with perfect surface quality for new low-friction coatings).
• Regional Shipbuilding Shift: The dominance of Asian shipyards is likely to continue. However, we may see growth in other regions like the Middle East and Southeast Asia for specialized or regional vessels. This could diversify supply chains but keep overall demand high.

A Projected Demand Scenario for Key Products:
It is useful to think about relative growth rather than exact numbers.

My Long-Term View from the Supply Side:
Our business strategy is already aligned with this 2030 outlook. We are deepening partnerships with mills that invest in producing advanced grades and bulb flats⁴. We are also enhancing our certification and traceability systems because 2030’s ships will need full digital material passports⁷. The client feedback we value most talks about long-term planning. When our partner in Saudi Arabia says they plan future orders for L-shaped and bulb flat steel, it shows they are building their business around this multi-year demand trend. For anyone in the marine steel business, the path to 2030 is clear: the demand for steel will be strong, but it will be increasingly focused on smarter, greener, and more efficient steel products. Positioning your supply chain now for that future is the most important step you can take.

Conclusion

Bulb flat steel demand is rising sharply in Asia, fueled by the construction of efficient, large vessels. This growth is part of a broader, long-term increase in demand for specialized marine steel driven by global decarbonization goals.