The term "open slab" is a commonly used, informal name. According to the revised GB709 standard, what was previously referred to as an open slab and original slab should now be called shear steel and single-rolled steel, respectively.
When steel Plates are produced in the steel mill, they are typically rolled into large coils. Once these coils are unrolled and flattened by machines, the resulting flat sheets are known as "open slabs." Think of it like a roll of toilet paper—when you unroll it, the material experiences higher internal stress, which can lead to instability in dimensions. During the opening process, different operational parameters can affect how the internal stresses are distributed, resulting in varying load-bearing capacities in different directions. These variations are not easily measurable using conventional strength indicators. As a result, when open slabs are welded, they tend to warp significantly, making it hard to correct after the fact. This makes them unsuitable for applications where appearance quality is critical.
Open slabs are steel plates that are originally shipped from the factory in a coiled form, and they are cut to specific thicknesses and widths based on customer requirements. In contrast, original slabs are rolled to meet national standard dimensions before being shipped from the steel mill.
Typically, original slabs have tighter dimensional tolerances, better mechanical properties, and are more expensive. Open slabs, while more affordable, may have slight variations in size and shape.
Flat plates generally range in thickness from 1.5mm to 20mm and are commonly made from grades such as Q235 or Q345. They are primarily used in non-pressurized containers and tanks where high structural integrity is not required.
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