Heat Resistant Steels...

Heat Resistant Steels The properties of steel and its yield strength considerably decrease as the steel absorbs heat when exposed to high temperatures. Heat resistance means that the steel is resistant to scaling at temperatures higher than 500 deg C.  Heat resistant steels are meant for use at temperatures higher than 500 deg C since they have got good strength at this temperature and are particularly resistant to short and long term exposure to hot gases and combustion products at temperature higher than 500 deg C. These steels are solid solution strengthened alloy steels. As these steels are used over a certain broad temperature ranges, these steels are usually strengthened by hard mechanism of heat treatment, solid solution and precipitation. All the heat resistant steels are composed of several alloying elements for the purpose of achieving the desired properties and are used in applications where resistance to increased temperatures is critical. The level of the heat resistance of the heat resistant steels depends on the environment conditions in which they operate and cannot be characterized by a single testing method. Maximum service temperatures which can be extended to 1150 deg C depending on the alloy content can be severely reduced by the presence of some compounds such as sulphurous compounds, water vapour or ash. Resistance to molten metal and slag is also limited in these steels. In heat resistant steels, the two most important elements are chromium for oxidation resistance and nickel for strength and ductility. Other elements are added to improve these high temperature properties. The effect of various alloying elements is described below. Chromium – Chromium is the one element which is present in all the heat resistant steels. Besides imparting oxidation resistance, chromium adds to high temperature strength and carburization resistance. Chromium...

Management of Time

Management of Time Time is a basic resource and hence it need to be spent judiciously. Management of time is the act or process of planning and exercising conscious control over the amount of time spent on specific activities, especially to increase effectiveness, efficiency or productivity as well as for carrying out the activities effortlessly in a natural way. Management of time may be aided by a range of skills, tools, and techniques when accomplishing specific tasks, projects and complying of goals within the due date. Management of time is required not only for business or work activities, but it also includes personal activities as well. A time management system is a designed combination of processes, tools, techniques, and methods. Time management is a necessity when a given task is to be completed in a specific time. Since time management is a management process just like any other, it must be planned, monitored and regularly reviewed. The absence of time management is characterized by last minute rushes to meet deadlines, meetings which are either double booked or achieve nothing, days which seem somehow to slip unproductively by, crises which loom unexpected from nowhere. This sort of environment leads to inordinate stress and degradation of performance. Poor time management is often a symptom of over confidence. The techniques which used to work with small projects and workloads are sometimes simply reused with large ones. But inefficiencies which were insignificant in the small role are ludicrous in the large. Time management includes the following: Creating an environment conducive to effectiveness. Setting of the priorities. Carrying out activity around the set priorities. The related process of reduction of time spent on non priorities. Time management covers how to eliminate tasks that do not provide an individual or an organization a value. According to...

Blast Furnace Cooling System Oct25

Blast Furnace Cooling System...

Blast Furnace Cooling System Fritz W Lurman, a well known blast furnace man of the time opined in 1892 that ‘irrespective of the use of so called refractory materials, the best means of maintaining the walls of the blast furnace is with cooling water’. Coolers with water circulating in them are installed between the shell of the blast furnace and the refractory lining in the upper part of the furnace to protect these components from heat radiation. In addition to having its own coolers, the part of the shell adjacent to the hearth and the bottom of the furnace is also cooled in some furnaces on the outside by water sprays. Function of blast furnace cooling system is to cool the furnace shell and prevent from the overheating and subsequent burn through. Cooling system removes the excess heat generated in the blast furnace which is otherwise loaded on the shell. Cooling system thus prevent the increase of the shell and lining temperature. Various methods exist for cooling of the shell for the blast furnace. In earlier times, cooling boxes of different size, number and design were used for transferring heat of the furnace to a cooling medium in conjunction with external cooling (spray cooling, double shell). Blast furnaces with cast iron cooling staves are operating since mid 1900s. Cast iron stave cooling was originally a Soviet discovery from where it travelled initially to India and Japan.  By 1970s, cast iron cooling staves have attained world wide acceptance. Since the introduction of these cast iron stave coolers, the development work of blast furnace cooling got accelerated and today a wide variety of coolers are available for the internal cooling of the furnace shell to suit extreme condition of stress in a modern large high performance...

Glossary of Terms used for Safety Management in a Steel Plant...

Glossary of Terms used for Safety Management in a Steel Plant The glossary of terms normally used for safety management in a steel plant is given below. Accident – An unplanned event that results in harm to people, damage to property or loss to process. Accident causation – The many factors that act together to cause accidents. They include (i) personal factors, (ii) job factors, and (iii) factors related to lack of management control. Accident investigation – The process of systematically gathering and analyzing information about an accident. Accident prevention – The systematic application of recognized principles to reduce incidents, accidents, or the accident potential of a system or organization. Confined space – It is an area which is not designed for continuous human occupancy and has limited opening for entry, exit and ventilation. Contract employee (Contractor) – An individual supplied by an external company (contractor, sub contractor, consultant or vendor) on a full or part time basis and who is providing a service (production, maintenance, or administrative support) to the organization. The contractor safety, health and well being are primarily supervised by the external contractor’s supervisor or manager. He is paid by the external company directly. The external company presents an invoice for the contract for service to the organization. Controls – These are measures designed to eliminate or reduce hazards or hazardous exposures. Emergency plan – It is detailed procedures for responding to an emergency such as fire, explosion, chemical spill or an uncontrolled release of gas or energy. Emergency plan minimizes the effects of a disaster. Employee (Company employee) – Employee is a person who is on the payroll of the organization. He has an employee number that identifies the person as an employee of the organization and who is directly...

Safety in a Steel Plant – General Aspects...

Safety in a Steel Plant – General Aspects The health, safety and protection of employees, equipment and the environment are of serious concern in a steel plant since steel plant is an industry of hazardous nature.  The health and safety of employees is crucial since it affects both economic and social factors. It is necessary that steel plant management recognizes the advantages of safe work environments and progressively adopt safety management practices to prevent hazardous events, avoid production and manpower losses and fall outs associated with the accidents. Seriously following of safety practices also assists enhancement of employee’s knowledge of operation, results into improvement of technical procedures, maintenance of accurate process safety information and increase in overall plant productivity. A safe work place also contributes towards plants competitiveness as well as in profit growth. As per Board of Directors of World Steel Association, “Nothing is more important than the safety and health of the people who work in the steel industry”. Following of safety practices results reduction of risk to a level that is as low as is reasonably predictable. There are three imperatives for adopting safety practices. They are ethical, legal and financial. There is a moral obligation placed on the steel plant management to ensure that the work place and the work activities are safe. There are legal requirements defined for safe working. Safe working also reduces down time, improves workman’s morale and promotes systematic working, resulting into substantial reduction in the cost of production and financial savings. The nature of various types of accidents is shown by an iceberg of incidents (Fig 1). They are unsafe actions, incidents, minor injuries, lost time injuries, serious accidents and fatalities. Fig 1 The iceberg of accidents Every steel plant should aim at accident. To...