decoiled steel sheet

"decoiled steel sheet" is a relatively colloquial term. In the revised GB709 standard, what is commonly referred to as "decoiled steel sheet" and "original flat plate" should be officially termed as "single-rolled steel plate" and "sheared steel plate," respectively.

When steel plates leave the steel mill, they are in coiled form. These steel plates are then flattened by machines, and the resulting flat plates are called "decoiled steel sheet." Much like a full roll of toilet paper, decoiled steel sheet have high levels of internal stress, resulting in poor dimensional stability. Depending on the process parameters during the leveling operation, the distribution of internal stress varies, leading to differences in load-bearing capacity along different directions relative to the length. Moreover, this load-bearing capacity is difficult to gauge using general strength indicators.

As a result, decoiled steel sheet experience significant welding deformation during welding, which is challenging to control. Therefore, they are not suitable for components with high requirements for appearance quality. Decoiled steel sheet are generally cheaper than standard steel plates.

Decoiled steel sheet typically range in thickness from 3 to 12 mm, with materials including Q235 and Q345. Major production sites include Wuhan, Jinan, Baotou, and Purui.

The primary applications are in non-pressure containers and storage tanks.

**Advantages of Decoiled steel sheet:**  
1. Lower cost and the ability to customize length.  
2. Convenient transportation without being constrained by standard steel plate dimensions.  
3. Ease of cutting, as they can be tailored to actual size requirements.  
4. Effective material savings. For example, if a storage tank requires 20 plates of 6800×1500×6 mm, and the market typically offers steel plates in lengths of 6000, 8000, or 9000 mm, using standard plates would result in leftover scrap materials. With decoiled steel sheet, 6900 mm plates can be directly used, minimizing waste. This is the most significant advantage, particularly for materials like stainless steel, where saving material substantially reduces costs.

**Disadvantages of decoiled steel sheet:**  
The drawback is that they undergo significant welding deformation during welding, which is difficult to control. Thus, they are not suitable for components with high appearance quality requirements.