Blast furnace productivity and the influencing parameters Jun23

Blast furnace productivity and the influencing parameters...

Blast furnace productivity and the influencing parameters Blast furnace (BF) is a process of iron making. During mid eighties BF technology got established and left behind other technologies of iron making. Since then continuous developments are taking place in this technology to make it more productive and economical. Even today it is offering very stiff opposition in the development of alternative iron smelting processes. The blast furnace is a counter current reactor in which the reducing gas is produced by the gasification of the carbon of the coke with the oxygen of the hot blast injected via tuyeres in the lower part of the furnace. The reducing gas flows upwards reducing the iron bearing materials charged at the top of the furnace. Blast furnace process consists of a multivariate system which is subjected to a large number of inter-influencing variables affecting the performance of the blast furnace. It is necessary to isolate the inter-influence of the variables to understand the role played each variable on the performance of the blast furnace. The performance of a blast furnace is determined by many parameters out of which productivity is the major one. The blast furnace productivity is the quotient between possible gas throughput per unit of time and required specific gas generation for one ton of hot metal (HM). Hence an increase in the productivity on the one hand requires an increase in the gas throughput, which implies improvement in the furnace permeability and on the other hand a reduction in the specific gas requirement, which means a reduction in the specific consumption of reducing agent. Blast furnace productivity is usually expressed in tons of hot metal produced/day/Cum of working volume. In some countries, in place of working volume, useful volume is considered. There are many factors which...

Electrode quality steel for core wire of covered electrodes...

Electrode quality steel for core wire of covered electrodes Covered welding electrode is a delicate tool which while in use combines physical, chemical, and metallurgical processes of the flux, core wire and parent metal to achieve a durable weld joint or surfacing. Covered welding electrodes are used in manual metal arc welding (MMAW) process. During the 1890’s, electric arc welding was accomplished with bare metal electrodes. The welds produced were porous and brittle because the molten weld puddle absorbed large quantities of oxygen and nitrogen from the atmosphere. Since 1927, many improvements have been made and many different types of electrodes have been developed and produced through variations in the formulations of the covering and the amount of covering on the mild steel core wire. Commercial production of welding electrodes was started in India in early 1960s. Mild steel covered electrodes, also commonly called coated electrodes, consist of only two major elements namely the core wire or rod and the flux covering. The raw material for the core wire is hot rolled wire rod which is supplied in coil form. Wire rod is cleaned, drawn down to the proper electrode diameter, straightened, and cut to the required electrode length. The most popular diameter of wire rod is 5.5 mm, although larger diameters are also used in a limited way. In covered welding electrode the product mix is of mild steel electrodes (around 60 %), mild steel high tensile and low hydrogen low alloy (around 30 %) and special type (around 10 %). Fig 1 shows EQ steel wire rod, EQ steel drawn wire and covered welding electrode. Fig 1 EQ steel wire rod, EQ steel drawn wire and covered welding electrode.  Core wire is an important component of a manual electrode since it significantly influences the electrode performance...

Disciplined way of working...

                      Disciplined way of working The concept of discipline is as old as man’s desire to form society. In fact, discipline is the pre-requisite of civilized life. It is indispensable to peaceful and orderly social life. Discipline is one of the basic requirements in a man’s life. It is a part of a standard way of living. A man without discipline can achieve nothing worthwhile in life. The strength of a man is mainly dependent on discipline. Discipline is the very condition of progress, stability and strength. Discipline is necessity in all walks of human life. Wise men preach discipline while great men practice it. Discipline is vital to every living being. It is essential in everyday life. Discipline cannot be acquired from books. Nor can it be learnt from teachers. It has to be a natural component in a man’s life. To be disciplined is always in our hand (Fig 1)    Fig 1 Discipline and us  Definition of discipline  Discipline is defined as a force that prompts individuals and groups to observe rules, regulations, systems, processes and procedures which are considered to be necessary for the effective functioning.It is also defined as an activity that involves acting in accordance with a set of known rules, proven guidelines and conventions framed for the purpose. It is basically an attitude of the mind, a product of culture and environment. Discipline refers to the regulation of behaviour of members of an institution involving rules that govern goal orientation and behaviour of members inside and outside the institution. Disciplined working  Discipline is an aspect of behaviour. It involves in using of using of sound methods with consistency. Disciplined working is needed most whenever human error can cause harm, substantial inconvenience or expense. Disciplined way of working is designed to reduce/eliminate...

Continuous casting mould powders Jun16

Continuous casting mould powders...

Continuous casting mould powders Continuous casting (CC) mould powder is used primarily to facilitate the passage of steel through the mould. It is also known by names such as casting powder, mould powder and mould flux. CC mould powder plays an important role in the continuous casting of liquid steels. It is one of the most critical and influential factors for smooth continuous casting of the liquid steel. CC mould powder is sprayed at the top of the liquid steel in the mould either manually or by automatic feeders. CC mould powder after additions in the mould Heat up and loose some carbon by reaction with oxygen Forms a sintered layer Melts at a definite rate and forms sintered (mushy) and liquid layers. The liquid layer acts as a reservoir to supply liquid slag to the strand. This liquid pool should be deeper than the stroke length to ensure good lubrication. Forms a solid slag film through the first infiltration of liquid slag into the mould/strand gap. This slag film is glassy in nature and is typically 2 to 4 mm thick. This slag subsequently crystallizes in the high temperature regions adjacent to strand. Forms a liquid slag film typically of 0.1 mm thickness. This liquid slag is drawn down into the gap along the steel shell and lubricates the strand. This lubrication prevents the steel from adhering to the mould thus removing a cause of the strand break out. Schematic diagram of different layers of mould powder after its addition in the mould is given in Fig. 1 Fig 1 Schematic diagram of different layers of mould powder after its addition in the mould  Besides the function of mould lubrication, CC mould powder has to perform some more basic functions. These other basic...

Forging quality steels...

Forging quality steels Forging quality steels are those steels which are subjected to the process of forging during its subsequent processing for the production of end use products. The process of forging consists of converting the steel material into designed shape at a higher strain rate. Forging quality steels have the property of forgeability which is the relative ability of the steel to flow under compressive loading without fracturing. Except for resulphurized and rephosphorized grades, most carbon and low alloyed steels are usually considered to have good forgeability. Difference in forging behaviour among the various grades of steel is small enough and hence selection of steel for a forging is seldom affected by the forging behaviour Forging process The forging process can be of the following three types. Hot forging – In this process the forging operation is usually done at a temperature of around 1200 deg C. Warm forging – This process is carried out below the recrystallization temperature of steel normally at temperatures ranging from 650 deg C to 750 deg C. Cold forging – This process is performed at room temperature and the steel material is not heated. During the process of forging, since high strain rates are employed, the qualities needed in forging steels are critical and demanding. Further forging components demand specialized treatments necessary for imparting special properties based on the end application of the forgings. Also since the end use of the forged steel products is of critical nature, a close control over all the stages of steel manufacturing process is required. Selection of steel for forging Selection of a type of steel for a forged component is an integral part of the forging process and accepted performance of the steel after forging is dependent on this choice....