Tensile Testing of Steel...

Tensile Testing of Steel Sample of steel is subjected to a wide variety of mechanical tests to measure their strength, elastic constants, and other material properties as well as their performance under a variety of actual use conditions and environments. Tensile test is one of them. Other tests are hardness test, impact test, fatigue test, and fracture test. These mechanical tests are used to measure how a sample of steel withstands an applied mechanical force. The results of such tests are used for two primary purposes namely (i) engineering design (e.g. failure theories based on strength, or deflections based on elastic constants and component geometry), and (ii) quality control either by the producer of steel to verify the process or by the end user to confirm the material specifications. Uniaxial tensile test is known as a basic and universal engineering test to achieve material parameters such as ultimate tensile strength (UTS), yield strength (YS), % elongation, % area of reduction and young’s modulus. Tensile testing is done for many reasons. The results of tensile tests are used in selecting materials for engineering applications. Tensile properties are often included in material specifications to ensure quality. Tensile properties are also normally measured during development of new materials and processes, so that different materials and processes can be compared. Also, tensile properties are generally used to predict the behaviour of a material under forms of loading other than uniaxial tension. Safely withstanding the expected maximum load without permanent deformation (or to stay within the specified deflection) is a basic requirement for a steel product. The ‘resistance’ against the load is a function of the cross-section and the mechanical properties (or in other words the ‘strength’) of the steel material. Tensile testing is done to determine the mechanical...

Organizational Competencies...

Organizational Competencies  Organizational competencies are the competencies needed in the organization so that it can excel and remain competitive in the market. The competencies provide an inventory of expected behaviours, skills and attitudes which lead to the successful performance of the organization. Organizational competencies depend heavily on the competencies of the employees of the organization. Organizational competencies, in the most general terms, are those ‘things’ which the employees of the organization are to demonstrate to be effective in their job, role, function, task, or duty. These ‘things’ include (i) job-relevant behaviour (what the employees say or do which result in good or poor performance), (ii) motivation (how the employees feel about a job, organization, or geographic location), and (iii) technical knowledge/skills (what the employees know/demonstrate regarding facts, technologies, their professions, procedures, jobs, and the organization, etc.). Competencies are identified through the study of jobs and roles. The term ‘competency’ is usually defined as a combination of skills, attributes and behaviours which are directly related to successful performance on the job. They are important for all the employees regardless of occupation, function, or level. An efficient organization keeps into focus the competencies on performance development/which enables its employees to align their individual performance with values and strategy while maximizing the individual performance in the pursuit of specific work-related objectives and behaviours. Organizational competencies can be broadly divided into (i) core values, (ii) technical competencies, and (iii) core competencies. Core values are the organizational values which are the shared principles and beliefs. These principles and belief unite all the organizational employees and guide them in their actions. Technical competencies are those specific competencies which are usually required to perform a given job within a job family. Technical competencies cover the various fields of expertise relevant to...

Circored and Circofer processes of ironmaking Feb24

Circored and Circofer processes of ironmaking...

Circored and Circofer processes of ironmaking Circored and Circofer processes of ironmaking are fluidized bed based iron ore fines reduction processes. These processes completely avoid agglomeration process and make direct use of iron ore fines. Since the processes use non coking coal, necessity of coke oven battery is not there. Fluidized bed technology is ideally suited to energy-intensive processes like direct reduction because it enables high heat and mass transfer rates. Both the Circored and the Circofer processes have been developed by Lurgi Metallurgie GmbH, Germany (now Outotec Oyj, Finland) for the production of direct reduced iron (DRI) from iron ore fines. For both processes, capacities above 1 million tons per annum are possible in a single production unit, resulting in improved economies of scale. Circored process is hydrogen (H2) based process while the Circofer process is coal based. Circored has a two-stage configuration in order to achieve a high metallization of 90 % to 95 %, whereas Circofer has a single-stage configuration which can achieve pre-reduction up to a metallization of around 70 %. Circofer coal-based process produces pre-reduced feed material for smelting reduction reactors, such as AusIron, or electric smelting furnaces – the final product being hot metal or pig iron. Circored process Circored process uses fluidized beds on a scale adopted by Outotec for other applications. Development of the process was initiated in the late 1970s with the pilot plant tests conducted at the ELRED plant of ASEA in Sweden. Tests were also carried out in the 3 tons per hour CFB reactor demonstration unit at Thyssen Stahl in Duisburg, Germany. These tests had focused on the treatment of steel plant wastes. The first commercial Circored unit was built in 1998 by Cliffs and Associates Ltd. at Point Lisas Industrial Complex...

Corrosion in Steels – Its Types and Testing...

Corrosion in Steels – Its Types and Testing Corrosion is a universal natural process. The effect of corrosion is seen in every-day life in the form of rusted steel parts. Corrosion has a huge economic impact. About a fifth of the global annual steel production goes towards simply replacing steel parts damaged by corrosion. Even though it involves higher up-front cost, correct and efficient corrosion protection at the source helps save money and resources in the long run. Failure due to corrosion can result into dramatic consequences. Corrosion is the gradual degradation of a metal by chemical, often electrochemical reaction with the surrounding environment. Corrosion results into loss of material properties such as mechanical strength, appearance, and impermeability to liquids and gases. Whether steel is corrosion resistant in a specific environment depends on the combination of the chemical composition of steel and the aggressiveness of the environment. As per ISO 8044:2010, corrosion is the physicochemical interaction between a metal and its environment, which results in changes in the metal’s properties and which may lead to significant functional impairment of the metal, the environment, or the technical system of which they form a part. Corrosion takes place when there is a change in the steel’s or system’s properties which may lead to an undesirable outcome. This can range simply from visual impairment to complete failure of technical systems which cause great economic damage and even present a hazard to the people. The typical corrosion process can be regarded as the thermodynamically favoured reverse reaction of the metal-winning (extraction) process (Fig 1). Like all chemical reactions, corrosion processes take place when conditions favour the related chemical reactions (thermodynamics). Then, potential other factors drive the speed of the reaction (kinetics). Fig 1  Chemical reactions of iron during...

Safety in Rolling Mills...

Safety in Rolling Mills Worldwide, as the rolling speeds are increasing, greater emphasis is being placed on the aspects of safety while designing the mill equipment as well as during the finalization of the mill layouts. Providing high importance to safety is in the best interest of the designers, manufacturers and the users of the rolling mills. Safeguarding of the mill equipment is necessary for ensuring the safe working of the rolling mill after its commissioning. Manufacturers of the rolling mills have the objective to produce a competitive mill, while users desire to have a highly productive mill. However, before any of these objectives can be met, both the manufacturer and the user are to first determine how to engineer the mill using safe design principles to minimize operator’s risks. Investing in a safer workplace also reduces the expenses of treating injured workers, helps preventing workplace accidents besides boosting employees’ morale by conveying the message that the organization cares about its employees and wants to protect their health and safety. A brief overview of safety requirements for the equipment of rolling mill is given below. Common safety related definitions Safety is the ability of the equipment to perform its function while being transported, installed, adjusted, operated, maintained, dismantled, and disposed of under conditions of intended use specified in the instruction manual without causing injury or damage to health of the people carrying out these functions. Risk is a comprehensive estimate of the probability and the degree of the possible injury or damage to the health in a hazardous situation in order to select appropriate safety measures. Hazard is a condition or set of circumstances which can cause physical harm to the exposed personnel. Danger zone is any zone within or around the equipment in...