Products with a rectangular cross-section, where the width is significantly greater than the thickness.
Note: The surface is typically smooth, except for specific products, such as checkered plates, which feature regular raised patterns or serrated surface patterns.
(#1 The term “coils” we commonly use is actually a very broad concept; cold-rolled and hot-rolled coils, medium- and heavy-gauge plates, narrow strips, and others are all collectively referred to as flat products. Of course, today we’ll focus only on uncoated products.)
1 Uncoated Flat Products
Flat products without any coating or surface treatment. Flat products that have undergone simple coatings to prevent rust or mechanical damage—such as passivation (#2: Here, passivation is best understood as a temporary protective process, whereas passivation after hot-dip galvanizing is considered a functional coating), organic protective layers, paper, oil, and paint—are also defined as uncoated flat products.
1.1 Hot-Rolled Uncoated Flat Products
Flat products obtained from hot-rolled semi-finished products or hot-rolled steel ingots. Hot-rolled uncoated flat products include those that have undergone slight cold flattening (generally with a deformation of less than 5%).
1.1.1 Wide Flat Steel
With a nominal width greater than 150 mm but not exceeding 1,250 mm, and a nominal thickness typically greater than 4 mm, these products are generally delivered in straight lengths rather than in coils, with sharp edges; wide flat steel is obtained by hot-rolling on all four sides (or using a box-type die) or by shearing or flame-cutting from wider flat finished products. (#3 Wide flat steel is a separate category; it is wider than the flat steel classified under long products, and cutting of wide material into strips is permitted.)
1.1.2 Hot-Rolled Sheets and Plates
The edges may be freely flared; the product is supplied in a flat form, generally square or rectangular, with a nominal width of not less than 600 mm. It may also be supplied in other shapes, such as rings, or as specified by drawings. The edges may be rolled, sheared, gas-cut, or machined. Finished products may be delivered in a pre-bent condition. Products with a nominal thickness less than 3 mm are classified as hot-rolled sheet, while those with a nominal thickness of 3 mm or greater are classified as hot-rolled plate. (#4 specifically refers to plates, which are commonly known as hot-rolled sheet and medium-to-heavy plate; a distinctive feature is that they may be delivered pre-bent. Also note the 3 mm threshold for hot-rolled thin sheets.)
Hot-rolled thin sheets and thick plates can be produced using the following methods:
a) Directly rolled on a reversible rolling mill (this product is generally referred to as single-pass rolled steel plate), or sheared from blank slabs rolled on a reversible rolling mill; (#5: What we conventionally refer to as medium- and heavy-gauge plates)