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)...

High Strength Carbon and Low Alloy Steels...

High Strength Carbon and Low Alloy Steels High strength carbon (C) and low alloy steels have yield strength (YS) greater than 275 N/sq mm and can be classified generally in four types namely (i) as-rolled C – Mn (manganese) steels, (ii) as rolled high strength low alloy (HSLA) steels also known as micro-alloyed steels, (iii) heat treated (normalized or quenched and tempered) C steels, and (iv) heat treated low alloy steels (Fig 1). These four types of steels have higher YSs than mild C steel in the as hot rolled condition. The heat treated low alloy steels and the as rolled HSLA steels also provide lower ductile-to-brittle transition temperatures than do C steels. Fig 1 Classification of high strength carbon and low alloy steels The four types of high strength steels have some basic differences in mechanical properties and available product forms. In terms of mechanical properties, the heat treated low alloy steels offer the best combination of strength and toughness. However, these steels are available primarily as bar and plate products and only occasionally as sheet and structural shapes. In particular, structural shapes (I and H beams, channels, or special sections) can be difficult to produce in the quenched and tempered condition since shape warpage can occur during quenching. Heat treating steels is also a more involved process than the production of as rolled steels, which is one reason the as rolled HSLA steels are an attractive alternative. The as rolled HSLA steels are also commonly available in all the standard wrought product forms (sheet, strip, bar, plate, and structural shapes). HSLA steels are an attractive alternative in structural. High strength steels are used to reduce section sizes for a given design load, which allows weight savings. Reductions in section size are also...