Corrosion of Carbon Steels...

Corrosion of Carbon Steels Carbon (C) steel is the most widely used engineering material. Despite its relatively limited corrosion resistance, C steels are used in large tonnages in marine applications, power plants (both nuclear based power and fossil fuel based power), metal processing equipment, power transmission, transportation, chemical processing, petroleum production and refining, pipelines, mining, and construction etc. The annual cost of metallic corrosion to the total economy of a country is very high. Because C steels represent the largest single class of alloys in use, both in terms of tonnage and total cost, it is easy to understand that the corrosion of C steels is a problem of enormous practical importance. This, of course, is the reason for the existence of entire industries devoted to providing protective systems for iron and steel. Because of corrosion, the design aspects are also very important. Indeed, design changes are often the most efficient manner of dealing with a particular corrosion problem. C steels also often called mild steels have limited alloy content, usually less than 2 % of the total of all the additions. These levels of additions do not generally produce any remarkable changes in general corrosion behaviour. One possible exception to this statement is the weathering steels, in which small additions of copper (Cu), chromium (Cr), nickel (Ni), and/or phosphorus (P) produce significant reductions in corrosion rate in certain environments. At the levels present in the C steels, the usual impurities have no significant effect on corrosion rate in the atmosphere, neutral waters, or soils. Only in the case of acid attack is an effect observed. In this latter case, the presence of P and sulphur (S) markedly increase the rate of attack. Indeed, in acid systems, the pure irons appear to show the...

Data based Decision making in a Steel Organization...

Data based Decision making in a Steel Organization During the operation of a steel plant a large amount of data gets generated. In a steel organization where there are a large number of units working in conjunction with each other and where there are a large variety of processes taking place simultaneously at all the times, the generated data is many times that of a normal organization. This huge amount of data need to be coordinated, collected, integrated, and analyzed in order to ensure that proper decisions are taken for the smooth running of the units, processes and ultimately the steel organization. Decisions taken based on analyzed data ultimately help in providing the organization a competitive advantage. Even without disturbances, unexpected situations and current rapid production changes in a steel organization are challenging for operators, maintenance personnel and production planners and management who make decisions. Hence, there is a need to have a systematic methodology to structure the decision making situations and to find out the relevant information and other needed factors. The performance of decision making depends on the quality of the decisions taken. Structuring the decision making situation means that all the relevant factors are considered and not forgotten, and action choices are found out and their effects are evaluated. This kind of approach produces cost-effective decisions. Data if collected and stored is only a lot of information available. For data based decision making, the data is to be structured and processed. Inter dependency of the data need to be understood and proper integration is to be done to have meaningful data analysis for decision making. Data is good, but only as good as the systems in place to collect summarize, analyze, make decisions, make action plans, implement interventions, and sustain implementation....

Blast Furnace Tuyeres and Tuyere Stocks May29

Blast Furnace Tuyeres and Tuyere Stocks...

Blast Furnace Tuyeres and Tuyere Stocks The blast furnace (BF) has the objective of extracting the hot metal (liquid iron) from iron ore lump, sinter and/or pellet, coke and injected fuel. This objective is achieved by passing a hot enriched air flow (hot blast air) through the ore and coke burden which goes down in the internal column of the BF. The hot blast air and auxiliary fuel are injected into the blast furnace through tuyeres located around the perimeter of the BF. The upper zone of the hearth wall of the blast furnace contains the openings for the tuyeres which are used to introduce the hot blast air into the furnace. The furnace jacket in the tuyere zone contains steel reinforced openings within which copper (Cu) cooled elements are installed, similar to that shown in Fig 1. The steel reinforcements in the jacket are called tuyere cooler holders. The large Cu cooler which is installed within the machined inner surface of the cooler holder is called the tuyere cooler. The Cu cooler which actually introduces the hot blast air into the furnace is called the tuyere. It is installed within a machined, inner seating surface on the tuyere cooler. The blowpipe is part of the tuyere stock air distribution piping, which delivers the hot blast air from the bustle pipe, and which mates with the tuyere, to direct the hot blast air into the furnace. The tuyere breast walls are usually made of carbon brick and the cooling is generally external with jacketed cooling channels on the outside of the shell. Some furnaces have internal staves in the tuyere breast between the tuyere coolers as a cooling design for the tuyere breast. Fig 1 also shows the arrangement of the tuyere cooler holder,...

Mechanical Properties of Steels...

Mechanical Properties of Steels The most important properties of steels which account for their widespread use are their mechanical properties. These properties include a combination of very high strength with the ability to bend rather than break. Different tests have been developed to describe the strength and ductility (a measure of bendability) of steels. A number of these tests which are used to describe the mechanical properties of steels are described below. Tensile testing Tensile testing of steel is a kind of a testing done for the evaluation of the strength of steels. A length of the steel material, usually a round cylindrical rod, is pulled apart in a machine that applies a known force, F. The machine has grips which are attached to the ends of the cylindrical steel rod, and the force is applied parallel to the axis of the rod, as shown schematically in Fig 1. As the force increases, the rod gets longer, and the change in length is represented as delta l (? l), where the symbol delta (?) means ‘a change in’ and the l refers to the original length of the rod. If a force of 50 kg is applied to two rods of the same steel material, where one is thin and the other thick then the thin rod elongate more. To compare their mechanical properties independent of rod diameter, the term ‘stress’ is used. Stress is simply the force divided by the cross-sectional area of the rod. When the same stress is applied to the thin and thick rods, they elongate the same amount, because the actual force applied to the thick rod is now larger than that applied to the thin rod by an amount proportional to its larger area. Because stress is force...

Outsourcing – A Management Technique...

Outsourcing – A Management Technique   Outsourcing is a usual practice among different organizations and is a one of the element of the organizational strategy.  Most of the organizations these days outsource some of the functions they used to perform themselves. Outsourcing is when any operation or process that could be (or would usually be) performed in-house by the organizational employees is sub-contracted to another organization for a substantial period. The outsourced tasks can be performed on-site or off-site. By outsourcing, the organization uses third parties to perform noncore activities of the organization. Contracting third parties enables the organization to focus its efforts on its core competencies. Third parties that specialize in an activity are likely to be lower cost and more effective, given their focus and scale. Through outsourcing, the organization can access the state of the art in all of its operational activities without having to master each one internally. The concept of outsourcing came from the American terminology ‘outside resourcing’, meaning to get resources from the outside. The term was later used in the economic terminology to indicate the use of external sources by an organization for some of the activities in its functioning. As per James Brian Quinn of The Outsourcing Institute, outsourcing started with organizations outsourcing physical parts. Now the big shift has been to outsource intellectually based service activities like research, product development, logistics, human relations, accounting, legal work, marketing, logistics, and market research. If an organization is not best-in- world in doing something and is doing it in-house, then it is giving up the competitive edge. In such a case the organization can outsource to the best in the world, up the value, and lower the cost. There are three major categories of motivations for outsourcing namely...