Structural steels

Structural steels Structural steel is a standard construction material made from specific steel grades and is available in industry standard cross sectional shapes. This steel exhibits desirable physical properties such as strength, uniformity of properties, light weight and ease of use etc. This makes it one of the most versatile structural materials in use. Major applications for these steels are in high rise and tall multi-storey buildings, industrial buildings, towers, tunnels, bridges, road barriers and industrial structures etc. The common shapes in which structural steels are available consist of sections (beams, channels, Tees section and angles), squares and rounds, hexagons, plates, pipes, hollow square sections, steel cable, Z sections and cold formed sections etc. (Fig 1). Fig 1  Some shapes of structural steels Structural grade steels have specific chemical compositions and mechanical properties required as per their application. These steels are produced as per the specifications included in different standards which are issued for structural steels. Structural steels for use at ambient or moderately elevated temperatures are of the following types. Carbon and carbon-manganese steels – In these steels the maximum content for alloying elements does not exceed the following: (i) manganese – 1.65 %, silicon – 0.40 % and (iii) copper – 0.6 %. The specified minimum of copper does not exceed 0.4 % and also there is no minimum content is specified for other elements to obtain a desired alloying effect. High strength low alloy (HSLA) steels – These steels have specified minimum yield strengths greater than 280 Newtons /Sq cm and achieve that strength in hot rolled condition rather than by heat treatment. Heat treated high tensile steels – Both Carbon and HSLA steels can be heat treated to provide yield strengths in the range of 350 to 520 Newtons/Sq cm....

Working with Systems and Procedures...

Working with Systems and Procedures In present day competitive environment, it is essential that for survival one performs very efficiently. He is to be one step ahead of his competitors in productivity and efficiency to be competitive. He should be in a position to foresee the future things and plan properly accordingly. He should continuously improve his performance so that he is not left behind during the changing environment in the times to come. Working with systems and procedures provides a person the necessary implements for this need. Procedures are series of steps constituting a planned method of carrying out an activity. A number of procedures make a system. Systems A system is a set of detailed methods, procedures and routines created to carry out a specific activity, perform a duty, or solve a problem. It is an organized, purposeful structure that consists of interrelated and interdependent elements (components, entities, factors, members and parts etc.). These elements continually influence one another (directly or indirectly) to maintain their activity and the existence of the system, in order to achieve the objectives of the system. Systems underlie every phenomenon and all are part of a larger system. Systems stop functioning when an element is removed or changed significantly. A typical system (Fig 1) has the following: Inputs, outputs and feedback mechanism Maintain an internal steady state despite a changing external environment Display properties that are different than the whole but are not possessed by any of the individual elements Have boundaries that are usually defined Fig 1 Schematic of a system At the basic level, systems are divided into the following two categories. Closed systems – Theses are theoretical systems that do not interact with the environment and are not influenced by its surroundings. Open systems – These are real world systems whose boundaries allow exchanges of energy, materials and information with the larger environment or system in which they exist  Procedures Procedures are step by step sequence of activities...

HIsarna process of iron making Jun28

HIsarna process of iron making...

HIsarna process of iron making HIsarna process is an ironmaking smelting reduction process where liquid iron is produced directly from iron ore fines and coal. This process eliminates prior processing of raw materials as needed by the blast furnace process. This process is an initiative of the ULCOS (ultra low CO2 steelmaking) consortium of European steelmakers. HIsarna is a combination of HIsmelt technology of Rio Tinto and the Isarna technology developed at Tata Ijmuiden. The process consists of pre-reduction of ore fines in cyclone converter furnace (CCF) of Isarna technology and bath smelting of iron in smelt reduction vessel (SRV) 0f HIsmelt process. The name of the process has been given by combining the names of the two technologies (‘HI’ from HIsmelt and ‘sarna’ from Isarna, a celtic word for iron). The process represents a new, potentially more efficient way of making iron. The technology is being developed in order to substantially reduce carbon emissions from the iron making process. Initial developmental work The very first attempt of applying cyclone technology in the reduction of the iron ore was attempted at Koninklijke Hoogovens in 1960s but the attempt was abandoned. Another serious attempt was made in 1986 but because economic crisis the project was put on the back burner until the early 1990s. The project was revived when coke supply became scarce during mid 1990s. CCF technology was then developed at a pilot scale with capacities of 15 to 20 tons per hour of ore feed. The attempt was again halted in 1999 due to successful implementation high pulverized coal injections in the blast furnaces. HIsmelt originally started By CRA (now Rio Tinto) in 1980s a 2 tons per hour HIsmelt pilot plant at Maxhutte, Germany followed by 8 tons per hour pilot plant in...

Ferroalloys

Ferroalloys Ferroalloys are alloys of iron with a high percentage of one or more of other elements. Ferroalloys industry is very closely related to iron and steel industry since ferroalloys are used in steel making, alloying of steels and in iron or steel foundries. In the production of steel, ferro alloys are used for deoxidation of steels as well as for introduction of the alloying elements in the steel. Ferroalloys impart distinctive qualities to steel and cast iron.  Depending upon the process of steel making and the product quality envisaged, the requirement of ferroalloys varies widely. Ferroalloys are usually classified into two groups namely (i) Bulk ferroalloys and (ii) Noble or special ferroalloys. More than 85 % of ferroalloys produced are used in the steel industry. Bulk ferroalloys Bulk ferroalloys consist of principal alloys namely ferro manganese (Fe-Mn), silico manganese (Si-Mn), ferro chrome/charge chrome (Fe-Cr) and ferro silicon (Fe-Si). These are shown in Fig 1. Fig 1 Bulk ferroalloys Ferro manganese – Fe – Mn is a ferroalloy with high content of manganese (Mn). It is produced by heating a mixture of the oxides of MnO2 and Fe203 with carbon usually as coal and coke, in either a blast furnace or a submerged arc furnace. The oxides undergo carbo thermal reduction to produce Fe- Mn. It is produced as three types of products namely (i) standard high carbon (C) Fe-Mn, (ii) medium carbon Fe-Mn and (iii) low carbon Fe- Mn. High carbon Fe – Mn has manganese in the range of 72 % to 82 %, C in the range of 6 % to 8 % and silicon (Si) in the range of around 1.5 %. Medium carbon Fe- Mn has manganese in the range of 74 % to 82 %, C in the...

Benchmarking process

Benchmarking process An organization to be successful needs to evaluate its performance in a consistent manner. In order to do so, the organization is to set standards for itself, and measure its processes and performance against recognized leaders in the field or against best practices from other fields, which operate in a similar environment. This process is normally known as benchmarking in management parlance. The objective of benchmarking is to find examples of superior performance and to understand the processes and practices driving that performance. Organization then improves its performance by tailoring and incorporating these best practices into its own operations—not by imitating, but by innovating. Performances which are normally measured are quality, time and cost. During the benchmarking exercise the organization learns the new processes which are superior to the processes being presently followed by them. By implementing these new processes the organization improves its performance. Organizations use benchmarking technique for the following objectives. To improve its performance To understand relative cost position and to identify opportunities for improvement To gain strategic advantage by focusing capabilities critical to building strategic advantage To increase the rate of organizational learning since the benchmarking exercise brings new ideas and facilitates experience sharing The benchmarking process is relatively uncomplicated. Some knowledge and a practical dent is all that is needed to make such a process, a success. Further benchmarking should not be considered as one time exercise. To be effective, it must a continuous process and should become an integral part of an ongoing improvement process with the goal of keeping abreast of ever improving best practice. Types of benchmarking Benchmarking process can be an internal process (comparing performance between different groups or teams within the organization) or an external process (comparing performance with other organizations working in similar environment)....