Raw steel

About 800 million metric tons of raw steel is produced annually throughout the world. Its usehilness is enhanced by the fact that it is inexpensive. The price as of the mid-1990s ranged from ca 440/kg for the common grades to several dollars per kg for special steels such as certain tool steels. Prices have remained relatively constant since the early 1980s. 

The abihty to tap an array of iron units to provide flexibiUty in all parts of the business cycle is a topic of great interest in keeping costs of raw steel down in the international arena. This is being combined with efforts to reduce the time for a given process by even a few seconds. 

Production. World production of raw steel, largely continuously cast, is shown in Table 6. U.S. production has approached 9.0 x 10 t/yi") over 90% of which is continuously cast. The amount melted in electric furnaces approached 40% and in 1995 was stiU increasing. 

Table 6. World Raw-Steel Production, 1000 Metric Tons...

TABLE 2. AVERAGE ENERGY RbQl IRfcMENTS FOR PROCESSING STEPS IK THF. PRODUCTION OF RAW STEEL... 

Because of the large supply of sulfur, there is increased interest in its possible use in the construction industry (7-13). This chapter reviews research at The University of Calgary concerned with sulfur in civil engineering applications. Large volumes of materials are required for construction. The amount of sulfur which is available may be compared with the consumption of some of the principal construction materials (Table I). In Canada the annual production of sulfur is already a sizeable fraction of the yearly consumption of some of these materials. For example the annual sulfur production is about half that of raw steel and about three quarters that of portland cement. Elsewhere sulfur production is much smaller than that of presently used construction materials, but there are indications that sulfur production will be increasingly important. 

It can be stated that on average, nearly 100 million tons of raw steel are produced. The inhibitors used in 1998 amounted to 50 million, and inhibitors used in steel production are expected to increase only slightly (1-1.5%) in the future. Like most systems requiring inhibition, the water treatment piping and vessels in both cooling and boiler water systems are the most affected. 

For many companies, raw steel represents up to 75% of total manufacturing costs. Therefore, reducing scrap and inventory costs are at the center of many cost-reduction efforts. Even the smallest reduction in these costs can have a dramatic effect on the company s bottom line. 

Modern steel-making is characterized by two difTerent material flows. In one of them raw iron (pig iron) is made from iron ore and then used to manufacture raw steel. In the other technique raw steel is made by melting scrap. As a matter of fact, steel scrap is an important raw material for steel-making. UtiHzing scrap is also an important component in modern environmental thinking and in the efforts currently being made to re-use industrial products, see Figure 8.22. 

Raw steel is refined by ladle processes to final steel, which is then cast by continuous casting into work pieces for final steel production by rolling or forging (billets, blooms and slabs). 

Electric steel furnaces are melting machines for the production of raw steel from scrap (Figure 8.24). The raw steel produced in this way can be directly used for some purposes but is, as a rule, refined to give steels of a higher quality. 

Figure 8.24 Electric furnace for the production of raw steel from scrap. (Reprinted from the booklet Steel with permission from Employers Association of the Swedish Steel and Metal Industry, Stockholm.)...

Country/Reglon Raw steel production, million tonnes... 

Additional constraints apply for production of alloyed or high alloyed Cr or Cr-Ni raw steel melts in the EAF. Melting of stainless steel scrap requires higher specific electrical energy demand due to higher specific heat cqiacity of Cr alloys and due to lower heat conductivity of... 

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