Classification of Steel Products produced in Steel Plants...

Classification of Steel Products produced in Steel Plants Steel products in general are classified as (i) castings, (ii) forged products, (iii) stamped products, (iv) bright products, (v) cold formed products, (vi) welded sections, (vii) wire and wire products, (viii) pipes, tubes, hollow sections and hollow bars, and (ix) powder metallurgy products. Steel products produced in steel plants are classified as per (i) stage of manufacture of the product, (ii) shape and dimensions of the product, and (iii) the product appearance. As per the stage of manufacture, the range of steel products produced in the steel plants are usually grouped into three main categories (Fig 1) namely (i) crude steel products, (ii) semi-finished steel products, and (iii) finished rolled steel products. Finished rolled steel products can be (i) hot rolled products, (ii) cold rolled products, and (iii) coated products.  Fig 1 Categories of steel products Crude steel products Crude steel products are either in the liquid state or in solid state. Liquid steel is normally used for the production steel castings. Crude steel in solid form was earlier considered as steel ingots which are produced by pouring liquid steel into iron moulds of a shape appropriate to the subsequent processing into semi-finished or finished steel products normally by hot rolling or forging. The shape of steel ingots usually resembles a truncated pyramid or truncated cone with the side surfaces may be corrugated and the corners more or less rounded. Steel ingots may be dressed and/or hot scarfed or cropped depending on the subsequent conversion requirements. Steel ingots can be distinguished based on their cross sections as (i) having a cross-section which can be square, rectangular (of width less than twice the thickness), polygonal, round, oval or shaped according to the profile to be rolled, (ii)...

Hot Rolled Steel Bars and Shapes...

Hot Rolled Steel Bars and Shapes Hot rolled steel bars and hot rolled steel shapes are produced from rolled in hot rolling mills or continuous cast blooms or billets and comprise a variety of sizes and cross sections. Bars and shapes are most often produced in straight lengths, but bars in some cross sections in smaller sizes are also produced in coils. The term ‘bar’ includes (i) rounds, squares, hexagons, and similar cross sections 10 mm and greater across, (ii) flats greater than 5 mm in thickness and 150 mm and less in width or greater than 6 mm in thickness and 200 mm and less in width, (iii) small angles, channels, tees, and other standard shapes less than equal to 75 mm across, and (iv) concrete reinforcement bars. The term ‘shape’ includes structural shapes and special shapes. Structural shapes are flanged, are 80 mm or greater in at least one cross-sectional dimension, and are used in structures such as bridges, buildings, ships, and railway wagons. Special shapes are those designed by users for specific applications.  Fig 1 shows various types of hot rolled bars and shapes. Fig1 Types of steel bars and shapes Dimensions, tolerances and surface imperfections The nominal dimensions of hot-rolled steel bars and shapes are designated in millimeters with applicable tolerances, as shown in the applicable standards. Bars or shapes can be cut to length in the rolling mill by a number of methods, such as hot or cold shearing or sawing. The method used is determined by cross section, grade, and customer requirements. Some end distortion is to be expected from most methods. When greater accuracy in length or freedom from distortion is required, bars of shapes are normally cut over-length, and then recut on one or both ends...