How Steel Coils are Safely Loaded onto Ships

How Steel Coils are Safely Loaded onto Ships - Merchant Navy Info - Blog

It is no mistake to say that steel is one of the foundations of the world economy. This widely used ferrous alloy is one of the most commonly produced. Processed, transported, and consumed materials in today’s supply chains. Steel is used in a variety of forms and for a myriad of purposes. From industry to agriculture, residential to municipal, and infrastructure to a product base. World steel production has increased more than tenfold over the past 70 years. And is expected to reach astronomical proportions in the future. This is the result of a population boom, globalization, rapid growth in infrastructure development. Increased production volumes, diversification of supply chains, and, of course, increased demand from all sectors. Steel and various steel products are important elements. In world trade and play an important role in the economic growth of any country. What are steel coils used for? 

Crude Steel Transportation  

After the hot steel is extracted from the blast furnace of the steelmaking furnace. The steel is work hardened and further processed. To improve  quality, strength, and other surface and internal material properties telling what are steel coils used for. It is then formed into slabs, ingots, sheets, billets, etc., for further use. This process is also known as steel casting. Bulk steel processed into these shapes is transported to a steel mill or other manufacturing facility. It is then processed into commercially available standard plates, rods, rods, beams, profiles, channels, pipes, etc. Depending on the initial stage of steel production, there are two types of rolling processes in steel rolling mills.

 The raw or semi-finished hardened steel is then cast into various shapes.

  1. Hot Rolling 
  2. Cold Rolling 

Hot Rolling

Hot rolling involves heating and rolling steel to very high temperatures (up to red heat). Cold rolling involves rapidly cooling the steel and treating it at low temperatures to improve its surface and mechanical properties. After cold rolling, the steel is ready for use. After partial processing of bulk steel after a hot rolling or complete processing of a steel after cold rolling. The steel is often coiled into large coils for convenient transportation and storage. Steel coil weights consisting of hot-rolled or semi-finished steel coil weights are called hot-rolled coils and require further processing and cold rolling before use. Hot-rolled steel coil weights are often rolled after annealing. what are steel coils used for?

Cold Rolling

Similarly, steel coils made of cold hardened, rolled, or fully machined steel are called cold rolled coils. Again, it has good surface and mechanical properties and. After proper molding, can be used in various products on the market. These steel coils are then unwound. And further processed or cold rolled (in the case of hot rolled coils) or processed into various products and items (in the case of cold rolled steel coils). Most of this steel is conveniently transported by cargo ship. The transportation of this steel is an important part of the freight market in commercial supply chains. We also know that these giant cylindrical coils are handled at cargo terminals and transported overland in trucks and trailers. However, special regulations and guidelines apply to properly store and transport these coils in large quantities on board ships.

Loading Steel Coils onto Ships

These steel coils are normally shipped in bulk and loaded into designated holds of ships accordingly. These steel coils weigh approximately 40-50 tons. Therefore, before loading, you must decide: 

  1. The hold will be cleaned, rinsed with fresh water and thoroughly dried. All residues such as rust, scale, flakes, and other contaminants must be removed. Additionally, residual gas must be removed from the hold before loading. According to regulations,  after cleaning the cargo hold, a third party “cleaning certificate” must be obtained.
  2. Prestress testing of steel coils is essential.
  3. Assess cargo hold integrity and watertightness, as well as the integrity of hatches and openings,  ventilation, and loading crane systems.
  4. Thoroughly inspect cargo holds and carefully mark sharp edges and points.
  5. Ensure the existence of a loading and safety manual with appropriate loading plans. For practical reasons, according to the SOLAS VI regulation, security manuals must be in place for all types of cargo, but steel coils are not subject to a specific framework. Therefore, it is the responsibility of operators and cargo managers to load cargo safely and properly and to make optimal use of the available space. 

Loading and Unloading Process 

The loading process is carefully carried out using cranes and derricks, both on board the ship and at the cargo terminal or port. The coil is usually suspended through a geometric center, and the suspension point is usually a wrap or loop of braided steel wire. A chain is not included to prevent damage to the steel surface. The utmost care is taken to ensure that the coils  (especially cold rolled and finished products) are intact and the surfaces are not damaged. When handling these coils with a forklift, circular or circular lifting profile tines are used instead of traditional rectangular tines with sharp edges. 

This can damage the steel surface or distort the center of the coil. The coils are always aligned with the ship’s fore-and-aft direction. This means that the circular center of gravity is always aligned with the longitudinal direction of the ship. Permanently fixed laterally at the bottom to prevent rotational movement and damage. To avoid damage to the steel surface and ensure a sufficient friction to prevent the coil from rolling, the coil is usually placed on horizontally placed wooden boards, the so-called storage layer. Typically about 25-30 mm thick, it acts as an intermediate layer between the coil and the ship’s plating. 

Additionally

Additionally, a significant portion of the coil’s structural loads can be absorbed and then distributed evenly throughout the ship’s structure. This dunnage has been carefully pre-dried to ensure that there is no moisture that could pose a risk of rust or corrosion to the steel coils. The locking wedge is further pinned to ensure that any movement occurring within the coil during navigation is stopped, and the resulting dynamic loads are transferred to the ship’s structure.

For practical reasons, loading coils are always placed in designated holds and never elsewhere on the deck or above the strength deck. Loading is carried out properly for optimal use of space but without abnormal or uneven loading on the coils. Additionally, dunnage ensures that the weight of these coils is not transferred to unreinforced parts of the plating (where local static, dynamic, and fatigue loads can occur), but rather to the lower plating or inner carefully placed so that it can be seen in the floor plating. 

For raised bottom containers) as a whole line distributed load, the maximum loads tend to act on the reinforcement and civil engineering components. On the one hand, this is problematic because it means that the total load capacity does not match the load capacity information listed in the information or loading guide. However, for practical reasons, steel coils are typically transported on large bulk carriers or other general-purpose carriers that are well-reinforced and have high design load ratings. Similarly, when unloading, carefully unlock all wedges and lashing straps and use the crane to lift the coils in sequence, starting from the top layer, just as when loading.

Storing and fixing 

After loading the steel coil, storing and fixing is also an important task. Steel coils vary in size and weight. Therefore, their loading philosophy is basically the same as any other type of cargo. If there is a large amount of such oil, it is loaded into the lower hold and loaded from the bottom up. To keep the center of gravity below the possible limit of vertical position, the heavier spool is loaded first and held in the lower area, and the lighter or smaller spool is held in the upper part. The coils are strapped or bandaged together using appropriate fasteners. They are placed on the side of the ship and on several floors or levels to accommodate a large number of coils. The coils are fixed together between two successive layers. 

When storing multiple rows of coils, leave at least 4 to 6 inches of distance between the two rows to avoid contact forces and  damage during loading and unloading. The center coil, also known as the key coil, is selected in both horizontal and vertical central positions, with the steel strip facing both the adjacent steel coil and the steel coil below it. Straps are hard metal, tensioned, and, in modern systems, are often pneumatic. Each key coil is placed on the lowest layer of coils, fixed, and positioned. The lower end of the diameter is at least one-third of the geometric diameter of the lower coil below the upper tip of the lower coil. However, it must not exceed 60% of the diameter of the top or key coil.

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